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Piping Systems Commensurate with Risk, but Proactive Measures Could 
Help Address Future Leaks' which was released on June 21, 2011. 

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United States Government Accountability Office: 
GAO: 

Report to Congressional Requesters: 

June 2011: 

Nuclear Regulatory Commission: 

Oversight of Underground Piping Systems Commensurate with Risk, but 
Proactive Measures Could Help Address Future Leaks: 

GAO-11-563: 

GAO Highlights: 

Highlights of GAO-11-563, a report to congressional requesters. 

Why GAO Did This Study: 

All U.S. nuclear power plant sites have had some groundwater 
contamination from radioactive leaks, and some of these leaks came 
from underground piping systems. The Nuclear Regulatory Commission 
(NRC) regulates nuclear power plants to protect public health and the 
environment from radiation hazards. GAO was asked to (1) determine 
experts’ opinions on the impacts, if any, of underground piping system 
leaks on public health and the environment; (2) assess NRC 
requirements of licensees for inspecting these systems and monitoring 
and reporting on leaks; (3) identify actions the nuclear power 
industry, licensees, and NRC have taken in response to leaks; and (4) 
identify additional NRC requirements, if any, that key stakeholders 
think could help prevent, detect, and disclose leaks. GAO convened 
expert discussion groups through the National Academy of Sciences and 
asked experts to review three case studies, analyzed documents, 
visited seven plant sites and two NRC regional offices, and 
interviewed stakeholders. 

What GAO Found: 

While experts in our public health discussion group generally agreed 
that radioactive leaks at the three nuclear power plants in our case 
studies of actual events had no discernible impact on the public’s 
health, these experts noted that additional information could enhance 
the identification of the leaks and the characterization of their 
impacts. The experts in our environmental impact discussion group 
concluded that environmental resources beyond the plant site have not 
been impacted discernibly, but that on-site contamination could affect 
plant decommissioning; for example, the licensee may have to conduct 
costly remediation to meet NRC regulations for unrestricted release of 
the site. Experts also identified the need for licensees to 
transparently report monitoring data and for licensees’ groundwater 
monitoring programs to be independently reviewed. 

NRC inspection requirements focus on ensuring the functionality of 
underground piping systems that are essential for both the safe 
operation and the shutdown of plants rather than providing information 
about the condition of the underground piping systems. In addition, 
NRC’s groundwater monitoring requirements generally focus on 
monitoring off-site locations, where a member of the public could be 
exposed to radiation, but not on on-site groundwater monitoring, which 
can improve the likelihood that leaks will be detected before they 
migrate off-site. 

In response to leaks, the nuclear power industry has implemented two 
voluntary initiatives to increase public confidence in plant safety. 
The first initiative was intended to improve on-site groundwater 
monitoring to promptly detect leaks. The second was intended to 
provide reasonable assurance of underground piping systems’ structural 
and leaktight integrity. Licensees’ responses to detected leaks have 
varied, ranging from repairing the leak source and documenting the leak’
s extent, to performing extensive mitigation. In addition, NRC has 
assessed its regulatory framework for, and oversight of, inspection of 
underground piping systems and groundwater monitoring. Based on the 
low risk posed by spills to date, NRC determined that no further 
regulations are needed at this time but has committed to such actions 
as gathering information on underground piping leak trends and 
reviewing codes and standards for underground piping. 

Key stakeholders identified additional NRC requirements that they 
thought could help prevent, detect, and disclose leaks. Some saw a 
need for NRC to require licensees to inspect the structural integrity 
of underground piping using techniques used in the oil and gas 
industry, while noting the challenges to applying such techniques at 
nuclear power plants. Industry is undertaking research to overcome 
these challenges. Stakeholders also noted that NRC should enhance its 
on-site groundwater monitoring requirements to promptly detect leaks 
and minimize their impacts. Finally, stakeholders said that NRC should 
require licensees to provide leak information in a more timely fashion 
and should make that information more accessible to the public. 

What GAO Recommends: 

GAO recommends that NRC periodically assess the effectiveness of the 
groundwater initiative and determine whether structural integrity 
tests should be included in licensee inspection requirements, when 
they become feasible, based on industry research. 

NRC stated it agrees with the report and recommendations and asserted 
that NRC has taken relevant actions. 

View [hyperlink, http://www.gao.gov/products/GAO-11-563] or key 
components. For more information, contact Frank Rusco at (202) 512-
3841 or ruscof@gao.gov. 

[End of section] 

Contents: 

Letter: 

Background: 

According to Experts, Underground Piping Leaks at Three Nuclear Power 
Plants Had No Discernible Impact on Public Health or the Environment, 
but More Information Could Enhance Identification of Leaks and 
Characterization of Their Impacts: 

NRC Requires Licensees to Inspect the Function of Their Safety-Related 
Underground Piping Systems, Monitor the Plant Environs for Radiation, 
and Report Releases in a Timely Manner: 

The Nuclear Power Industry, Licensees, and NRC Have Taken a Variety of 
Actions in Response to Underground Piping Leaks: 

Several Stakeholders Recommended That NRC Enhance Its Inspection, 
Groundwater Monitoring, and Reporting Requirements: 

Conclusions: 

Recommendations for Executive Action: 

Agency Comments and Our Evaluation: 

Appendix I: Objectives, Scope, and Methodology: 

Appendix II: Case Studies for Experts' Consideration: 

Appendix III: Comments from the Nuclear Regulatory Commission: 

Appendix IV: GAO Contact and Staff Acknowledgments: 

Tables: 

Table 1: Radiation Protection Limits: 

Table 2: Nuclear Power Plant Site Visits: 

Table 3: Summary of Underground Piping System Leak Case Studies: 

Table 4: Braidwood Land Use Survey Results: 

Table 5: Doses to the Public from Vacuum Breaker Releases (mrem/yr): 

Table 6: Oyster Creek Generating Station Land Use Survey Results: 

Table 7: Vermont Yankee Land Use Census Results: 

Figures: 

Figure 1: U.S. Operating Commercial Nuclear Power Reactors: 

Figure 2: Hypothetical Radioactive Leak from a Nuclear Power Plant 
Underground Piping System. 

Figure 3: NRC Regional Offices: 

Figure 4: Braidwood Generating Station: 

Figure 5: Oyster Creek Generating Station: 

Figure 6: Location of Oyster Creek Generating Station: 

Figure 7: Oyster Creek Generating Station Site Boundary: 

Figure 8: Oyster Creek Well Locations Associated with Buried Pipe Leak: 

Figure 9: General Location of Vermont Yankee Nuclear Power Station: 

Figure 10: Site Location Photo of Vermont Yankee Nuclear Power Station: 

Abbreviations: 

AOG: Advanced Off-Gas: 

ASME: American Society of Mechanical Engineers: 

BWR: Boiling Water Reactor: 

cfs: cubic feet per second: 

EPA: Environmental Protection Agency: 

ESW: Emergency Service Water: 

Fe-55: Iron-55: 

GPM: gallons per minute: 

kg/yr: kilograms per year: 

L/yr: Liters per year: 

MDA: minimum detectable activity: 

MOU: memorandum of understanding: 

mrem: millirem: 

mrem/yr: millirem per year: 

MWt: megawatts-thermal: 

Ni-63: Nickel-63: 

NPDES: National Pollutant Discharge Elimination System: 

NRC: Nuclear Regulatory Commission: 

pCi/L: picocuries per liter: 

NEI: Nuclear Energy Institute: 

OCGS: Oyster Creek Generating Station: 

PWR: Pressurized Water Reactor: 

Sr-90: Strontium-90: 

Te-99: Technetium-99: 

Vernon Dam: Vernon Hydroelectric Dam: 

VYNPS: Vermont Yankee Nuclear Power Station: 

[End of section] 

United States Government Accountability Office: 
Washington, DC 20548: 

June 3, 2011: 

The Honorable Edward Markey: 
The Honorable Peter Welch: 
House of Representatives: 

In recent years, a number of nuclear power plants have experienced 
leaks of radioactive materials from pipe systems that are underground 
and not easily accessible. Many of these underground pipe leaks 
resulted in contamination of groundwater by tritium--a radioactive 
form of hydrogen. In some instances, the contamination has migrated, 
or is expected to migrate, beyond the plant's boundaries, raising 
concerns about potential impacts on public health and the environment. 
The Nuclear Regulatory Commission (NRC), an independent federal agency 
headed by five commissioners, licenses commercial nuclear power plants 
and regulates and oversees their safe operation and security. NRC's 
mission includes protecting public health and the environment from 
radiation hazards. 

Most nuclear power plants have extensive underground piping systems, 
[Footnote 1] some of which transport water containing radioactive 
isotopes, such as tritium. While the amount and type of underground 
piping systems vary significantly among nuclear power plants, 
according to NRC officials, most of these underground systems are not 
safety-related--that is, they are not necessary to ensure reactor 
integrity, shut down and safely maintain the reactor, or prevent or 
mitigate the public's exposure to radiation during an accident. As 
nuclear power plants age, their underground piping systems tend to 
corrode, but since these systems are largely inaccessible and 
difficult to inspect, the condition of many underground piping systems 
at plants across the country is unknown. Further, as pipes continue to 
age and further corrosion occurs, the likelihood and severity of leaks 
could increase without mitigating actions. 

In the past decade, increased reports of buried pipe leaks at nuclear 
power plants have attracted significant attention and generated public 
concern about NRC's oversight of underground piping systems, 
particularly since NRC has issued few violations in association with 
these leaks.[Footnote 2] Specifically, stakeholders--such as 
environmental and antinuclear groups, as well as some scientists and 
engineers--have questioned the adequacy of NRC requirements pertaining 
to the safety of underground piping systems and are also seeking to 
understand the factors responsible for underground piping system 
leaks. Some stakeholders also have concerns about NRC's license 
renewal process. As most aging power plants have been applying for--
and receiving--20-year extensions of their operating licenses, some 
stakeholders have filed contentions, including contentions to prevent 
the relicensing of some plants with underground piping systems that 
may be subject to leaks.[Footnote 3] 

In this context, you asked us to review underground piping systems and 
NRC's requirements for them. Our objectives were to (1) determine 
experts' opinions on the impacts, if any, that underground piping 
system leaks have had on public health and the environment; (2) assess 
NRC requirements of licensees for inspecting underground piping 
systems and monitoring and reporting on leaks from these systems; (3) 
identify actions the nuclear power industry, licensees, and NRC have 
taken in response to underground piping system leaks; and (4) 
identify, according to key stakeholders, what additional NRC 
requirements, if any, could help prevent, detect, and disclose leaks 
from underground piping systems. 

To address these objectives, we consulted with experts, analyzed 
documents, conducted visits to selected plant sites and NRC regional 
offices, and interviewed stakeholders. Specifically, we worked with 
the National Academy of Sciences to convene two groups of six experts 
each,[Footnote 4] in January 2011. The first group addressed the 
public health impacts of underground piping system leaks, and the 
second one addressed their environmental impacts. We asked both groups 
of experts to discuss the impacts of leaks in the context of three 
case studies of nuclear power plants that have experienced leaks in 
their underground piping systems: Braidwood Generating Station in 
Illinois, Oyster Creek Generating Station in New Jersey, and Vermont 
Yankee Nuclear Power Station in Vermont.[Footnote 5] We selected these 
case studies because they included plants with underground piping 
system leaks that generated significant publicity and resulted in high 
concentrations of tritium detected in on-site groundwater. 
Additionally, the case studies included a plant at which contamination 
from a leak was detected off-site (Braidwood). We also analyzed 
relevant NRC regulations and requirements and interviewed NRC 
officials from the Office of Nuclear Reactor Regulation, Office of 
General Counsel, Region I, and Region III. In addition, we selected a 
nonprobability sample[Footnote 6] of seven nuclear power plants, most 
of which had recently experienced an underground piping system leak, 
and one of which had not experienced a publicized pipe leak, and made 
site visits to these locations to interview licensee representatives 
and NRC resident inspectors. During the site visits, we also observed 
ongoing activities related to mitigation of leaks. Finally, using a 
standard set of questions, we interviewed a nonprobability sample of 
over 30 stakeholders including representatives from NRC, other federal 
and state agencies who have worked on issues related to underground 
piping system leaks and associated groundwater contamination, 
representatives from industry and industry groups, standards-setting 
organizations, and advocacy and other interested groups, as well as 
independent consultants and experts. A more detailed description of 
our objectives, scope, and methodology is presented in appendix I. We 
conducted this performance audit from May 2010 to June 2011, in 
accordance with generally accepted government auditing standards. 
Those standards require that we plan and perform the audit to obtain 
sufficient, appropriate evidence to provide a reasonable basis for our 
findings and conclusions based on our audit objectives. We believe 
that the evidence obtained provides a reasonable basis for our 
findings and conclusions based on our audit objectives. 

Background: 

Currently 104 commercial nuclear power plants operate in the United 
States, together generating, as of 2007, about 20 percent of our 
nation's electricity. These reactors are located at 65 sites across 
the country (see figure 1) and are operated by 26 different companies. 
Many reactors built in the late 1960s and early 1970s are reaching or 
have reached the end of their initial 40-year license. As of March 
2011, NRC had renewed 63 reactor licenses for an additional 20 years 
and was currently reviewing 19 license renewal applications. 

Figure 1: U.S. Operating Commercial Nuclear Power Reactors: 

[Refer to PDF for image: illustrated U.S. map] 

The map depicted the location of commercial nuclear power reactors, as 
follows: 

Years of commercial operation by the end of 2010: 10-19; 
Number of reactors: 3. 

Years of commercial operation by the end of 2010: 20-29; 
Number of reactors: 48. 

Years of commercial operation by the end of 2010: 30-39; 
Number of reactors: 46. 

Years of commercial operation by the end of 2010: 40 or more; 
Number of reactors: 7. 

Sources: NRC (data); Map Resources (map). 

[End of figure] 

Since 2008, NRC has been collecting data from licensees on groundwater 
contamination incidents at nuclear power plants that have resulted 
from unplanned or uncontrolled releases of radioactive material, 
including leaks from underground piping systems. Based on these data, 
NRC has concluded that all 65 reactor sites in the United States have 
experienced a leak or spill of radioactive material into groundwater. 
NRC estimates that between 10 and 20 percent of groundwater 
contamination events at nuclear power plants can be attributed to 
leaks from underground piping systems.[Footnote 7] Figure 2 provides a 
diagram of a hypothetical underground piping system leak at a nuclear 
power plant. In addition, NRC data suggest that groundwater 
contamination events have been more prevalent during the last several 
years; however, the agency attributes this apparent increase to the 
nuclear industry's enhanced monitoring efforts and increased reporting 
of leaks during the same time period. 

Figure 2: Hypothetical Radioactive Leak from a Nuclear Power Plant 
Underground Piping System: 

[Refer to PDF for image: illustration] 

Nuclear power plant: 

Damaged pipe: 
Tritium plume within sand and stone layer beneath plant, detected by 
Monitoring well. 
Below sand and stone layer are: 
upper clay; 
lower clay; 
Aquifer. 

Source: NRC. 

[End of figure] 

NRC strives to accomplish its mission of protecting public health and 
safety and the environment by establishing regulations and standards 
governing licensed activities and inspecting facilities to ensure 
compliance with requirements. NRC prioritizes its oversight and 
inspections of structures, systems, and components that are critical 
to safely operating the plant during normal conditions and safely 
cooling the reactor core in the case of an emergency shutdown. 
Therefore, these structures, systems, and components are classified by 
NRC as "safety-related." 

NRC maintains staff at commercial nuclear power plants to inspect, 
measure, and assess their safety performance--and respond to any 
deficiency in performance--through its Reactor Oversight Process. 
Furthermore, according to NRC inspection protocols, performance 
deficiencies by the company licensed to operate a nuclear power plant, 
or licensee, can result in more intensive NRC oversight and/or 
issuance of a violation. However, to assure licensees that 
requirements placed on them will change only when they are justified 
from a public health and safety standpoint, the "backfit rule" 
[Footnote 8] requires that NRC make the determination that new 
requirements will result in a substantial increase in the overall 
protection of public health and safety and that this increased 
protection justifies the cost of implementing the new requirement. 
[Footnote 9] 

NRC's regulations allow certain levels of radioactive materials to be 
discharged into the environment. As a part of its license application, 
a licensee performs calculations of its expected releases,[Footnote 
10] and NRC reviews these calculations to verify their validity and 
conformance to NRC requirements. NRC's review and verification are 
documented in reports,[Footnote 11] and the licensees are required to 
monitor their discharges. Most of the systems used to discharge these 
radioactive materials are not classified as "safety-related." 
According to NRC officials, the amount of radioactive materials 
released from underground piping system leaks has been small relative 
to these permitted discharges. Furthermore, the officials noted that a 
leak of tritium in and of itself is not a violation of NRC 
requirements. 

NRC has established several layers of radiation standards to protect 
the public against potential health risks from exposure to radioactive 
releases from nuclear power plant operations (see table 1). In 
addition to these standards, the Environmental Protection Agency (EPA) 
developed drinking water standards for radioactive isotopes using its 
authority under the Safe Drinking Water Act. These limits apply to 
public drinking water systems but are also used by many state 
authorities as groundwater protection standards. For tritium, EPA set 
a maximum contaminant level of 20,000 picocuries per liter 
(pCi/l).[Footnote 12] None of the reported underground piping system 
leaks to date have exceeded NRC limits on the public's exposure to 
radiation, nor have reported concentrations of radioactive materials 
in off-site groundwater exceeded EPA standards for drinking water. 

Table 1: Radiation Protection Limits: 

Radiation protection layer: As low as reasonably achievable dose 
objective for liquid releases[A]; 
Annual dose limit: 3 millirem (mrem)[B] to the whole body and 10 mrem 
to any organ of an individual who lives in close proximity to the 
plant boundary; 
Basis: A fraction of the natural background radiation dose, and an 
attainable objective that nuclear power plants could reasonably meet. 

Radiation protection layer: EPA radiation standards incorporated as 
NRC regulations[C]; 
Annual dose limit: 25 mrem to the whole body, 75 mrem to the thyroid, 
and 25 mrem to any other organ of an individual member of the public; 
Basis: Limit is cost-effective in reducing potential health risks from 
nuclear power generation facilities' operation. 

Radiation protection layer: NRC dose limit[D]; 
Annual dose limit: 100 mrem to any individual members of the public; 
Basis: International Commission on Radiological Protection[E] 
recommendation that a lifetime of exposure at this limit would result 
in a very small health risk and is roughly equivalent to background 
radiation from natural sources. 

Source: NRC. 

[A] 10 C.F.R. Part 50, App. I. 

[B] A millirem is a unit for measuring biological damage from 
radiation. 

[C] 10 C.F.R. § 20.1301(e). 

[D] 10 C.F.R. § 20.1301(a)(1). 

[E] The International Commission on Radiological Protection is an 
organization of international radiation scientists who provide 
recommendations regarding radiation protection related activities, 
including dose limits. 

[End of table] 

When unplanned releases do not exceed NRC dose limits, NRC 
requirements allow for licensees to remediate the residual 
radioactivity at the time the site is decommissioned. For a 
decommissioned nuclear power plant site to be released for 
unrestricted use, NRC requires that it be cleaned up to an established 
minimum radiation annual dose limit. In addition to this requirement, 
NRC has entered into a memorandum of understanding (MOU) with EPA on 
cleanup of radioactively contaminated sites. The MOU includes 
provisions for NRC to consult with EPA if a site meets NRC cleanup 
standards but exceeds EPA-permitted levels.[Footnote 13] 

According to Experts, Underground Piping Leaks at Three Nuclear Power 
Plants Had No Discernible Impact on Public Health or the Environment, 
but More Information Could Enhance Identification of Leaks and 
Characterization of Their Impacts: 

According to the experts in our public health discussion group, no 
impacts on public health have been discernible from leaks at the three 
case study nuclear power plants we asked the expects to consider. 
Experts in our environmental expert group also said that no impacts 
from these leaks on off-site environmental resources have been 
discernible to date but that the on-site impacts over time are less 
certain. Finally, experts in both groups believe that additional 
information could help facilitate the identification of any future 
leaks and characterize their impacts. 

According to Experts in Our Public Health Discussion Group, Leaks at 
Three Plants Have Had No Discernible Impact on Public Health but May 
Have Affected Local Communities in Other Ways: 

Radioactive leaks at three power plants in Illinois, New Jersey, and 
Vermont have had no discernible impact on the public's health, 
according to the participants in our expert discussion group on the 
public health impacts of the leaks. More specifically, although the 
experts observed that the risk of impacts to the public's health is 
not zero, it is immeasurably small. While tritium was detected in the 
on-site groundwater at each of these plants from one or more leaks, it 
was detected in an off-site drinking water well only in the case of 
the Illinois plant. The experts noted that, based on the information 
reported by the licensees and NRC on off-site contamination levels, 
the radiation doses to the public from leaks at these plants have been 
very low--well below NRC regulations for radiation exposure, and 
orders of magnitude below any exposure that could cause an observable 
health effect. 

While the experts concluded that leaks at these plants have not 
discernibly impacted the public's health, some of them noted that the 
leaks may affect people in the surrounding communities in a less 
tangible manner. For example, according to two of the experts, even if 
community members have not been exposed to radiation from the leaks, 
the perception that contamination could exist in their community or 
that they cannot trust the operators of a nearby nuclear power plant 
can degrade individuals' quality of life. In addition, another expert 
noted that reported leaks at nuclear power plants could have an impact 
on the property values in the surrounding community based on the 
perception that the leaks could impact public health. Some of the 
experts observed that such perceptions are not taken into account in 
NRC's regulatory framework, which is based on protecting public health 
and safety. However, they noted that, for NRC or licensees to build 
trust and gain credibility, they should consider these perceived 
impacts when determining their actions to address a leak. A few 
experts said that better communication and complete transparency with 
the public about the risks associated with very low doses of radiation 
would be required to change the public's perception of the impacts 
associated with the leaks. However, one expert acknowledged the 
difficulty in effectively communicating the complex issue of risks to 
the public posed by low doses of radiation. Another expert suggested 
that communication with the public may be more effective if it is done 
through someone outside of industry with higher credibility from the 
community's perspective. 

No Impacts on Off-site Environmental Resources from Leaks at the Three 
Plants to Date Have Been Discernible, but Future On-site Impacts Are 
Less Certain, and Some Risks May Not Be Fully Understood, according to 
Experts in Our Environmental Impacts Discussion Group: 

Based on the information that is available on the case studies 
considered by the experts, the experts in our environmental impacts 
discussion group concluded that the leaks have had no discernible 
impact on off-site environmental resources. The experts noted that the 
leaks are unlikely to have an environmental impact if they do not 
affect public health, since humans are probably more sensitive to the 
effects of tritium contamination than most other organisms. However, 
two experts noted that very little information exists on the 
sensitivity of other organisms to impacts from environmental tritium 
contamination. Consequently, subtle effects on other organisms that 
have not been identified could exist. 

A few experts pointed out that even though off-site environmental 
impacts are not discernible, the on-site groundwater contamination 
from the leaks may have degraded the on-site environment, potentially 
limiting the site's future use. The on-site groundwater tritium 
contamination resulting from two of the case study leaks was detected 
in concentrations over 100 times the EPA drinking water standard. 
Consequently, some of the experts noted that when a licensee 
decommissions a plant with this level of groundwater contamination, 
the licensee may have to conduct costly remediation to be able to meet 
NRC regulations for unrestricted release of the site, or the site 
could have deed restrictions placed on its future use. Some of the 
experts debated whether the time frames for decommissioning current 
nuclear power plant sites would be sufficient for existing tritium 
contamination to naturally decay to levels required for unrestricted 
release of the site.[Footnote 14] Regardless, one of the experts noted 
that the licensees and NRC need to monitor high levels of current on- 
site contamination and ensure it does not move off-site in the future. 

Experts in Both of Our Groups Said That Additional Information Could 
Help Facilitate the Timely Detection of Leaks and Characterize Their 
Impacts, and Experts Identified the Need for More Transparency and 
Independent Review of Information: 

According to the experts in both of our discussion groups, to 
facilitate the detection of leaks in a timely manner, it is important 
that licensees have a thorough understanding of the site's subsurface 
environment and identify risk areas. NRC requires characterization of 
a site's hydrogeology--the groundwater and other subsurface 
characteristics--as a part of the evaluation process to choose an 
appropriate site for construction of the nuclear power plant. However, 
one expert pointed out that any construction on-site can significantly 
modify how groundwater flows through the subsurface, so it is very 
important to have current knowledge of a site's hydrogeology. In 
addition, experts also said that it was very important for licensees 
to have knowledge of their underground infrastructure and to identify 
critical systems, structures, and components where a leak might occur. 
This knowledge would enable licensees to strategically place their 
monitoring wells in order to have confidence that they will promptly 
detect leaks. 

Additional information could help characterize the impacts of leaks, 
according to the experts. More specifically, the experts noted that 
industry currently lacks standardized data across nuclear power plants 
to characterize the impacts of leaks and that data used to inform 
assessments of risk are limited to the locations where samples are 
collected. Experts said that, to obtain a complete picture of a leak's 
consequences, monitoring wells need to be placed in the proper 
locations, which must be informed by a thorough understanding of a 
site's hydrogeologic characteristics. Finally, the experts noted that 
licensees need to have conservative models that can predict how 
contamination would move if a leak were to occur, how long it would 
take for contamination to migrate off-site or contaminate a drinking 
water well, and what impacts there might be to public health and the 
environment. 

Finally, experts identified the need for licensees' monitoring data 
and assessments of impacts to be more transparent and to be 
independently reviewed to provide greater public confidence in them. 
One expert noted that groundwater data collected voluntarily by the 
licensees should be part of their annual environmental reports. 
Another expert observed that the groundwater reports prepared 
voluntarily by industry typically oversimplify presented data. In 
addition, experts expressed concern that there is no process for an 
agency or third party to review licensees' groundwater monitoring 
programs. For example, one expert observed that licensees, with their 
consultants, independently develop their voluntary groundwater 
monitoring programs, collect the data, and report the results without 
a formal opportunity for NRC or others to comment on the specifics of 
the programs such as the number, location, and depth of monitoring 
wells. Another expert noted that the results of licensees' modeling of 
radiation doses to the public from a leak should also undergo an 
independent review. Such a review could assess whether a different 
conclusion might have been reached if, for example, monitoring wells 
were placed in a different location. This is important, according to 
one expert, because NRC relies on licensees to initially determine 
whether a leak presents a health risk. 

NRC Requires Licensees to Inspect the Function of Their Safety-Related 
Underground Piping Systems, Monitor the Plant Environs for Radiation, 
and Report Releases in a Timely Manner: 

NRC inspection requirements related to underground piping systems at 
all 104 U.S. nuclear power plants focus on ensuring the functionality 
of safety-related piping systems, monitoring the plant environs for 
radiation, and reporting planned and unplanned releases.[Footnote 15] 
Specifically, NRC requires licensees to periodically test a sample of 
safety-related piping. Pipes are designated as safety related if they 
are essential to safely operate the plant or safely shut it down in 
case of an emergency. NRC inspection regulations, through the adoption 
of applicable American Society of Mechanical Engineers (ASME) Code 
provisions,[Footnote 16] require licensees to perform only pressure 
tests or flow tests on their safety-related underground piping 
systems. The pressure test is used to determine if and to what extent 
pressure is being lost within a section of piping, while the flow test 
is designed to identify any reduction in flow volume. To pass these 
tests, the pipes must be able to transport fluids at or above a 
specified minimum pressure or flow rate, which can be accomplished 
even when pipes are leaking. According to NRC, the agency's primary 
concern is whether a system is providing enough water to maintain its 
functionality at one point in time, which is what the results of the 
pressure and flow tests indicate. 

NRC regulations also require that licensees monitor the "plant 
environs"[Footnote 17] for radioactivity that may be released from 
normal plant operations, as well as from unplanned leakage such as 
leaks and spills, to ensure the protection of the public's health and 
safety. NRC requires that licensees establish and implement a site- 
specific Radiological Environmental Monitoring Program to obtain data 
on measurable levels of radiation and radioactive materials in the 
environment. Consistent with NRC guidance for this required monitoring 
program, licensees conduct radiation monitoring at locations where a 
member of the public could be exposed to radiation to identify whether 
levels of off-site radiation exceed federal dose limits. For example, 
agency guidance recommends quarterly monitoring of off-site 
groundwater only if it is used as a direct source of drinking water or 
irrigation and is likely to be contaminated. The agency does not 
generally require that licensees monitor groundwater on-site if it is 
not used for drinking water.[Footnote 18] However, if a licensee's 
monitoring program found radioactive materials off-site, additional on-
site monitoring could be required. With on-site monitoring, future 
leaks and spills have a higher likelihood of being detected before 
contamination reaches the site boundaries. Even though NRC has not 
generally required licensees to have on-site groundwater monitoring 
wells, most plants have installed some on-site wells that could help 
detect and monitor leaks. Although some contamination has been found 
to migrate off-site, thus far, according to NRC, reported off-site 
contamination has not exceeded EPA drinking water standards or NRC 
radiation exposure limits. 

In addition, NRC regulations require that planned and unplanned 
releases be reported to NRC by licensees in a timely manner.[Footnote 
19] For example, each licensee must submit a written report to NRC 
within 30 days after learning of an inadvertent release above 
specified limits of radioactive materials, such as tritium. The 
licensee's report must include a description of the extent of exposure 
of individuals to radiation and radioactive material. These NRC 
reporting requirements are in addition to their immediate notification 
of incidents requirements. Immediate notification, via an Emergency 
Notification System or telephone, is required for certain events or 
situations that may have caused or threatens to cause an individual to 
receive a high dose of radiation.[Footnote 20] 

The Nuclear Power Industry, Licensees, and NRC Have Taken a Variety of 
Actions in Response to Underground Piping Leaks: 

In response to underground piping leaks at nuclear power plants, the 
nuclear power industry adopted two voluntary initiatives largely 
intended, according to the Nuclear Energy Institute (NEI),[Footnote 
21] to enhance public confidence in the operation and maintenance of 
their plants. The actions specified in these initiatives, according to 
NRC officials, are above and beyond NRC requirements. Groundwater 
incidents that occurred around the 2005 time frame led to the 
industry's Groundwater Protection Initiative in 2007,[Footnote 22] 
which was intended to boost public confidence in the safe operation of 
the plants and to improve groundwater monitoring at nuclear power 
plant sites to promptly detect leaks. All licensees of operating 
commercial nuclear power plants in the United States have committed to 
the groundwater initiative and, in so doing, have agreed to perform a 
site hydrogeologic characterization and risk assessment, establish an 
on-site groundwater monitoring program, and establish a remediation 
protocol. 

After 2007, additional underground piping leaks were reported, 
heightening public concern about the degradation of buried pipes at 
nuclear power plants. As a result, NEI announced another voluntary 
industry initiative in 2009.[Footnote 23] This second initiative-- 
called the Buried Piping Integrity Initiative--was designed to provide 
reasonable assurance of structural and leaktight integrity of all 
buried pipes. All licensees of operating commercial nuclear power 
plants in the United States have committed to this initiative as well. 
The initiative defined a series of milestones for, among other things, 
assessing the condition of buried pipes and establishing a plan for 
managing them. Specifically, under this initiative, licensees agreed 
to rank their buried piping based on the likelihood and consequences 
of its failure and to develop an inspection plan using the results of 
the risk ranking, along with other factors, to prioritize the 
selection of locations at which they will inspect pipes. The 
initiative placed special emphasis on buried piping that is safety-
related and/or contains radioactive material. In 2010, the Buried 
Piping Integrity Initiative was expanded to the Buried 
Piping/Underground Piping and Tanks Integrity Initiative to address 
additional structures. All of the licensees have also committed to 
implement the expanded initiative. 

Licensees' actions in response to identified leaks at their power 
plants have varied, ranging from simply repairing the leak source and 
documenting the extent of the leak for future cleanup, to performing 
extensive mitigation. Specifically, at six of the seven sites we 
visited that had experienced underground piping system leaks, most of 
the licensees had identified and repaired the leak source and 
conducted remediation and/or monitoring of the groundwater 
contamination. For example, when we visited the Vermont Yankee Nuclear 
Power Station, the soil near the identified leak source had been 
excavated and removed by a radiological waste company hired by the 
licensee. In addition, at the Oyster Creek Generating Station in New 
Jersey, the licensee had undertaken a mitigation project to excavate 
some of its buried piping, either moving the pipes aboveground or 
placing them in vaults that can be monitored for leakage. 

NRC's response to underground piping leaks has taken various forms. 
First, NRC's response to individual leaks has generally been an 
increase in oversight at the particular plant, and not issuance of a 
violation, because most of the leaks have not posed a safety risk. For 
example, after an April 2009 leak at Oyster Creek Generating Station, 
NRC sent out regional inspectors to review and evaluate the 
circumstances associated with the leak. At other power plants, NRC's 
enhanced review has included overseeing some of the groundwater 
sampling activities that were performed to characterize leaks. In many 
of these instances, NRC relied upon split sampling--sending portions 
of some of the groundwater monitoring samples to a laboratory and 
comparing its analytical results with those obtained by the licensees' 
laboratories for the same samples--to verify the licensees' results. 

Furthermore, NRC reviewed its oversight of buried piping and took 
actions on the basis of its review. In particular, in the fall of 
2009, after several reported leaks from buried piping resulted in 
groundwater contamination and increased media coverage, NRC's Chairman 
tasked the agency staff with reviewing activities NRC had taken 
related to buried pipe leaks. The resulting December 2009 report 
concluded that the agency's regulations for the design, inspection, 
and maintenance of safety-related buried piping are adequate to ensure 
buried piping can perform its safety function.[Footnote 24] The report 
also identified a number of ongoing activities, such as conducting 
direct visual inspections of piping when a licensee excavates 
underground piping for the purpose of repair and replacements. In 
2010, NRC developed a Buried Piping Action Plan under which it would 
collect a variety of information, including data on buried pipe system 
leaks; assess the implementation of the industry's Buried 
Piping/Underground Piping and Tanks Integrity Initiative; participate 
in reviewing professional codes and standards for buried pipes; and, 
if warranted, develop responding regulatory actions. 

In 2010, NRC actions also included revising its Aging Management 
Program guidance for licensees to manage the effects of aging on 
structures or components for license renewal. The revisions include 
more detailed and comprehensive guidance for preventing and mitigating 
corrosion of underground piping systems and inspecting them. In 
addition, NRC proposed requirements for additional groundwater surveys 
for decommissioning. 

Moreover, in 2010 and 2011, NRC reviewed the extent to which the 
industry has implemented the Groundwater Protection Initiative but did 
not evaluate its effectiveness. During this review, NRC found that 
most plants have implemented most but not necessarily all steps 
outlined in the voluntary initiative. To insure full implementation of 
the initiative, NRC plans to continue observing the long-term 
implementation of this initiative through its Reactor Oversight 
Process. However, NRC has no plans to evaluate the extent to which 
this initiative, as implemented, will promptly detect leaks and, as a 
result, has no assurance that the Groundwater Protection Initiative 
will consistently help to promptly detect leaks as nuclear power 
plants age. In addition, NRC officials have said they will continue to 
review the status of the initiative's implementation, but said that 
the agency is not going to incorporate the initiative into its 
requirements because of the low level of risk associated with the 
reported leaks to date. Therefore, the public cannot be assured the 
initiative will remain in place in the future. 

In addition, in 2010 NRC convened a Groundwater Task Force composed of 
NRC staff to evaluate NRC's actions to address incidents of 
groundwater contamination at nuclear power plants and identify actions 
for a senior management review group to consider. Later that year, the 
task force issued a report that concluded that NRC is accomplishing 
its stated mission of protecting the public health and safety and the 
environment through its response to leaks and spills that contaminated 
groundwater. However, the report also concluded that NRC's response to 
leaks and spills has varied widely and that NRC should further 
consider ways to communicate more timely and complete information to 
the public about these incidents. In early 2011, NRC reported the 
results of its senior management's review of the Groundwater Task 
Force report findings. This report included four areas in which the 
agency committed to action: (1) identifying and addressing policy 
issues related to groundwater contamination; (2) enhancing the 
agency's Reactor Oversight Process; (3) developing specific actions in 
response to key themes and conclusions of the Groundwater Task Force 
report; and (4) conducting a focused dialogue with other regulators, 
such as EPA and states, to develop a collaborative approach for 
enhanced groundwater protection. 

Several Stakeholders Recommended That NRC Enhance Its Inspection, 
Groundwater Monitoring, and Reporting Requirements: 

Several stakeholders noted that NRC should enhance its inspection 
requirements for underground piping systems to help prevent leaks. In 
addition, several stakeholders suggested that NRC make its groundwater 
monitoring requirements more stringent to help detect leaks. 
Furthermore, according to some stakeholders, NRC should require more 
timely disclosure of information on leaks and make this information 
more accessible to the public. The stakeholders we interviewed 
included representatives from NRC, other federal and state agencies, 
industry and industry groups, standards-setting organizations, and 
advocacy and other interested groups, as well as independent 
consultants and experts. 

Several Stakeholders Identified Enhancements NRC Could Make to Its 
Inspection Requirements: 

Several of the stakeholders we interviewed said that NRC should 
enhance its inspection and testing requirements by requiring that 
licensees visually inspect underground piping more frequently and 
regularly, inspect piping's structural integrity,[Footnote 25] and 
inspect and test nonsafety-related piping that contains radioactive 
material. Many stakeholders who recommended more frequent and regular 
inspections pointed out that NRC requires direct visual inspection of 
underground pipes only when a pipe has been excavated for another 
purpose.[Footnote 26] While some stakeholders wanted NRC to require 
visual inspections even if that meant licensees would have to excavate 
underground piping to do so, one stakeholder pointed out that pipes 
can be damaged during excavation and that some pipes may not be 
accessible through excavation if, for example, they lie under a road 
or building. 

In addition, some stakeholders we interviewed recommended that NRC 
require inspections of structural integrity of safety-related 
underground piping systems, which can be susceptible to corrosion as 
plants age. NRC officials and other stakeholders noted that the 
pressure and flow tests NRC currently requires do not provide 
information about the structural integrity of an underground pipe, 
such as whether the pipe has degraded to the point that the thickness 
of its wall could hinder the pipe's future performance. One 
stakeholder voiced concern that not having structural integrity 
information about safety-related underground piping systems could 
create a very significant risk to public health and safety if such 
pipes were to unexpectedly fail due to corrosion. Moreover, some of 
the stakeholders we interviewed noted that some of the inspection 
techniques used in the oil and gas industry to provide additional 
information about the structural integrity of underground pipes could 
be used in the nuclear power industry. However, these stakeholders 
recognized that applying such techniques at nuclear power plants may 
be difficult, largely because the technology for such tests has not 
been sufficiently developed for, or adapted to, the nuclear industry 
site conditions. For example, guided wave technology--a method that 
transmits ultrasonic energy through a pipe's walls and monitors how 
the energy is reflected back to identify areas where a pipe may have 
corrosion--is used in the oil and gas industry, which tends to have 
miles of relatively straight piping through which waves can travel 
with little interference. However, the underground piping at nuclear 
power plants tends to include many bends and turns, which can distort 
the wave energy and interfere with the inspection test results. In 
addition, the oil and gas industry uses robotic devices sent through a 
pipe to capture images of its condition and identify areas of 
corrosion, but the bends and turns in pipes at nuclear power plants 
limit the use of robotic devices by the nuclear power industry. 
Although obtaining information about the structural integrity of pipes 
is currently challenging, based on stakeholders' observations, NRC and 
licensees cannot be assured that underground safety-related pipes 
remain structurally sound without having information about degradation 
that has occurred. Without such assurance, the likelihood of future 
pipe failures cannot be as accurately assessed, and this increases the 
uncertainty surrounding the safety of the plants. 

Industry and standards-setting organizations have undertaken 
activities to address the challenges of inspecting the structural 
integrity of underground piping systems at nuclear power plants. For 
example, industry, through the Electric Power Research Institute, has 
undertaken research to develop new, and improve upon existing, 
techniques to provide reliable and usable results, and some licensees 
are trying these techniques at their plants. The licensee at the 
Seabrook Station, for instance, has plans to pilot test a mechanical 
robot that was developed by the Electric Power Research Institute to 
detect cracks in underground piping. In addition, stakeholders 
representing standards-setting organizations, such as NACE 
International and ASME, noted that they have undertaken efforts to 
evaluate and enhance current technologies and codes for inspecting 
underground piping systems.[Footnote 27] For example, according to a 
member of NACE International, the organization formed a buried piping 
task group to, among other things, evaluate the current state of 
inspection techniques and technologies for underground piping systems 
and determine how they could be applied at nuclear power plants. 

Moreover, various stakeholders mentioned the need for NRC to require 
inspections and testing of nonsafety-related piping that contains 
radioactive material. Although NRC currently does not generally 
require such inspections,[Footnote 28] nonsafety-related piping has 
been the source of many reported leaks that resulted in groundwater 
contamination. For example, nonsafety-related piping was the source of 
leaks at the Oyster Creek and Braidwood plants. Some stakeholders said 
that any system whose failure could result in contamination of the 
environment should be prioritized for inspection and testing, even if 
it is not classified as being safety-related. 

According to NRC stakeholders, NRC has limited ability to enhance the 
licensees' inspection requirements of nonsafety-related underground 
piping systems, given the low level of risk associated with reported 
leaks to date, and the requirement that NRC justify the cost of new 
requirements relative to this risk. However, according to industry 
stakeholders, the voluntary Buried Piping/Underground Piping and Tanks 
Integrity Initiative may address stakeholder concerns related to 
inspection of nonsafety-related underground piping that carries 
radioactive material. This initiative includes a component under which 
licensees assign a risk rank to segments of their underground piping 
based on the potential for and consequences of failure. As a result, 
systems that are safety-related and systems that contain radioactive 
materials receive a higher rank. According to the initiative, systems 
with a higher rank will be prioritized for inspection and testing, so 
industry stakeholders noted that piping containing radioactive 
materials would receive more attention under the initiative. 

Several Stakeholders Suggested More Stringent On-site Groundwater 
Monitoring Requirements: 

Several of the stakeholders we interviewed noted that NRC should have 
more stringent requirements for licensees to monitor on-site 
groundwater to quickly detect leaks. Industry stakeholders 
acknowledged the importance of detecting leaks early to minimize their 
consequences. A few stakeholders said they would like to see NRC 
require that licensees install groundwater monitoring wells in the 
vicinity of potential leaks based on a risk-informed assessment of the 
underground piping systems that have the highest likelihood of leaking 
and a current and thorough assessment of the site's hydrogeology. Some 
stakeholders noted, however, that NRC should allow flexibility for 
licensees to determine the best approach to detect leaks at their own 
sites and to adapt their approach on the basis of evolving industry 
experience. 

However, according to stakeholders at NRC, as is the case with 
inspection requirements, the agency is unlikely to be able to justify 
changing its groundwater monitoring requirements given the low level 
of risk associated with reported leaks. Nevertheless, industry and NRC 
stakeholders noted that components of the industry's voluntary 
Groundwater Protection Initiative may address some stakeholders' 
concerns with respect to groundwater monitoring. For example, one of 
the objectives of the initiative is to establish an on-site 
groundwater monitoring program by considering placing wells closer to 
systems with the highest potential for inadvertent releases that could 
contaminate groundwater. Moreover, many NRC stakeholders noted that 
the industry initiative goes well beyond what the agency can do in 
terms of regulations and has already been implemented, whereas 
establishing new regulations could take years. In fact, a review 
performed by senior managers at NRC concluded that, in view of the 
progress being made by industry through the initiative, efforts to 
amend NRC's regulations to include the initiative are not necessary at 
this time. Moreover, industry stakeholders told us they do not 
consider the initiative to be voluntary since all of the power plants' 
chief nuclear officers committed to its implementation. Other 
stakeholders, however, told us that the language in the initiative is 
not strong enough and expressed concern that, because NRC has no 
authority to enforce the voluntary initiative, industry could move 
away from it at any point without recourse from NRC. 

Some Stakeholders Said That NRC Should Require More Timely Leak 
Information from Licensees and Should Make It More Accessible to the 
Public: 

According to some stakeholders, NRC should require licensees to report 
information about the level and extent of groundwater contamination 
from a leak and the licensee's assessment of a leak's impact in a more 
timely manner. One stakeholder noted that the inability to obtain 
timely information about leaks could undermine the public's confidence 
in NRC and licensee conclusions that a leak does not impact public 
health and safety. NRC currently requires licensees to make 
information on significant leaks available to the public by providing 
groundwater sample results and calculations of the radiation dose the 
public has received in its annual radioactive effluent and 
environmental reports. Consequently, even though NRC posts on its Web 
site some information about leaks as it becomes available, up to a 
year may pass between the time a leak occurs and the time the public 
receives information supporting the licensee's assessment of the 
leaks' impact. 

In addition, some stakeholders noted that NRC should make information 
pertaining to leaks more accessible to the public. For example, some 
of these stakeholders said that NRC could improve the accessibility of 
information on its Web site. Specifically, one stakeholder said that 
the site is difficult to navigate, cumbersome, and unnecessarily slow. 
Another stakeholder noted that staff members at his organization had 
used NRC's Web site to track information on groundwater contamination 
at a particular site, but the links they used were no longer available. 

Conclusions: 

The occurrence of leaks at nuclear power plants from underground 
piping systems is expected to continue as nuclear power plants age and 
their piping systems corrode. While reported underground piping system 
leaks to date have not posed discernible health impacts to the public, 
there is no guarantee that future leaks' impacts will be the same. 

Some of our stakeholders noted that a future leak could put the 
public's health and safety at risk if the leak went undetected for a 
long period of time. NRC's groundwater monitoring requirements are 
intended to identify when the public could be or has been exposed 
through drinking water to radiation doses above certain limits rather 
than to promptly detect underground piping system leaks. NRC has 
concluded that, in general, licensees' groundwater monitoring programs 
implemented under the voluntary groundwater initiative go beyond what 
the agency requires for groundwater monitoring and could enhance 
licensees' prevention of and response to potential leaks by detecting 
them early. However, without regularly evaluating the extent to which 
the initiative will result in prompt detection of leaks, NRC cannot be 
assured that groundwater monitoring programs under the initiative will 
detect leaks before they pose a risk to public health and safety. 

In addition, although NRC has acknowledged that the corrosion of 
underground piping systems, particularly those that are safety-
related, is a concern, limitations in the industry's ability to 
measure the wall thickness of an underground pipe without excavation 
prevent licensees from determining the structural integrity of 
underground piping systems. Without being able to identify that an 
underground piping system's structural integrity has not been 
compromised by corrosion, the risk to public health and safety is 
increased. In this context, licensees at nuclear power plants cannot 
assure that a safety-related pipe will continue to function properly 
between inspection intervals, thereby protecting the public's health 
and safety. 

Recommendations for Executive Action: 

To ensure the continued protection of the public's health and safety, 
we recommend that the Chairman of NRC direct agency staff to take the 
following two actions: 

* Periodically evaluate the extent to which the industry's voluntary 
Groundwater Protection Initiative will result in prompt detection of 
leaks and, based upon these evaluations, determine whether the agency 
should expand its groundwater monitoring requirements. 

* Stay abreast of ongoing industry research to develop technologies 
for structural integrity tests and, when they become feasible, analyze 
costs to licensees of implementing these tests compared with the 
likely benefits to public health and safety. Based on this analysis, 
NRC should determine whether it should expand licensees' inspection 
requirements to include structural integrity tests for safety-related 
underground piping. 

Agency Comments and Our Evaluation: 

We provided a draft of this report to NRC for its review and comment. 
NRC provided written comments, which are reproduced in appendix III, 
and technical comments, which we incorporated into the report as 
appropriate. NRC agreed with the information presented in the draft 
report and said they believe it to be fair and balanced. NRC also 
agreed with each of the report recommendations and asserted that they 
have established activities to address the recommendations. 

In responding to our recommendation to periodically evaluate the 
extent to which the industry voluntary Groundwater Protection 
Initiative will result in prompt detection of leaks and, based on 
these evaluations, determine whether the agency should expand its 
groundwater monitoring requirements, NRC stated that "the public can 
be assured that the NRC will continue to review the status of industry 
implementation of the initiative and consider regulatory changes as 
appropriate." Specifically, NRC said that it reviews reported 
groundwater monitoring results and changes to licensees' programs for 
identifying and controlling spills and leaks. However, as we reported, 
the agency has not assessed the adequacy of the licensees' groundwater 
monitoring programs, which were implemented under the Groundwater 
Protection Initiative, to promptly detect leaks. Absent such an 
assessment, we continue to believe that NRC has no assurance that the 
Groundwater Protection Initiative will lead to prompt detection of 
underground piping system leaks as nuclear power plants age. 

In addition, NRC agreed with our recommendation that it stay abreast 
of ongoing research on structural integrity tests; analyze the costs 
and benefits of implementing feasible tests; and, on the basis of this 
analysis, determine whether it should require structural integrity 
tests for safety-related piping. Further, NRC pointed out that it has 
established milestones to periodically assess both the performance of 
available inspection technology and the need to make changes to the 
current regulatory framework. Nevertheless, NRC said it "believes 
there is reasonable assurance that the underground piping systems will 
remain structurally sound." We believe that structural integrity 
tests, when feasible, would provide enhanced assurance of underground 
piping systems' structural soundness and enable more proactive 
oversight. As we reported, NRC's currently required pipe testing 
procedures--which provide information about a pipe's function at a 
particular point in time--do not indicate the presence of degradation 
in a pipe that could hinder its future performance. 

As agreed with your offices, unless you publicly announce the contents 
of this report earlier, we plan no further distribution until 30 days 
from the report date. At that time, we will send copies to the 
appropriate congressional committees, Chairman of NRC, and other 
interested parties. In addition, this report will be available at no 
charge on the GAO Web site at [hyperlink, http://www.gao.gov]. 

If you or your staff members have any questions about this report, 
please contact me at (202) 512-3841 or ruscof@gao.gov. Contact points 
for our Offices of Congressional Relations and Public Affairs may be 
found on the last page of this report. Key contributors to this report 
are listed in appendix IV. 

Signed by: 

Frank Rusco: 
Director, Natural Resources and Environment: 

[End of section] 

Appendix I: Objectives, Scope, and Methodology: 

Our objectives were to (1) determine experts' opinions on the impacts, 
if any, that underground piping system leaks have had on public health 
and the environment; (2) assess Nuclear Regulatory Commission (NRC) 
requirements of licensees for inspecting underground piping systems 
and monitoring and reporting on leaks from these systems; (3) identify 
actions the nuclear power industry, licensees, and NRC have taken in 
response to underground piping system leaks; and (4) identify, 
according to key stakeholders, what additional NRC requirements, if 
any, could help prevent, detect, and disclose leaks from underground 
piping systems. 

To determine experts' opinions on the impacts that underground piping 
system leaks have had on public health and the environment, we worked 
with the National Academy of Sciences to organize two half-day expert 
group discussion sessions in January 2011 to discuss (1) issues 
related to the public health risks associated with radioactive leaks 
from underground piping systems at nuclear power plants and (2) the 
environmental resource impacts from the leaks. In addition, we held a 
half-day plenary discussion session to follow up on questions left 
open during the public health impacts and environmental impacts group 
discussion and to discuss the overall characterization of impacts from 
leaks. 

In discussing the public health and environmental impacts of leaks, we 
asked the experts to consider three case studies of nuclear power 
plants that have experienced leaks from underground piping systems 
including Braidwood Generating Station in Illinois, Oyster Creek 
Generating Station in New Jersey, and Vermont Yankee Nuclear Power 
Station in Vermont. We compiled information packets on each of the 
case studies using sources such as NRC inspection reports, licensee 
environmental and effluent reports, Environmental Impact Statements 
prepared for license renewal, licensee hydrogeology reports, and 
licensee groundwater monitoring results and maps (see appendix II). 
The panelists were provided the information packets prior to the panel 
sessions. We selected these case studies because they included power 
plants that: 

* had among the highest detected on-site groundwater tritium 
concentrations that were associated with underground piping system 
leaks, 

* received a significant amount of publicity surrounding underground 
piping system leaks, and: 

* had contaminants from leaks that migrated off-site. 

The case studies selected had a range of cooling water sources, 
included both boiling water reactors and pressurized water reactors, 
and represented a range of plant ages with start of operations dates 
from 1969 to 1988. 

For the first discussion group on public health impacts from 
underground piping system leaks, the National Academy of Sciences 
invited qualified individuals with expertise in toxicology, health 
physics, public health, risk assessment, dosimetry, nuclear 
engineering, regulatory issues, and radiobiology. For the second 
discussion group on the environmental impacts of underground piping 
system leaks, the National Academy of Sciences invited individuals 
with expertise in the environmental effects of radiation, fate and 
transport of radioactive materials, civil engineering, water quality 
and remediation, hydrogeology, risk assessment, nuclear engineering, 
and regulatory issues. The invited experts had experience working in 
academia, consulting, and the federal government. None of the experts 
were compensated for their work on the discussion groups, and all 
experts were screened by the National Academy of Sciences for 
potential conflicts of interest. The following experts participated in 
the discussion sessions: 

Discussion Group on Public Health Impacts: 

* Jerome Puskin, U.S. Environmental Protection Agency:
* Phaedra S. Corso, University of Georgia:
* Chris G. Whipple, ENVIRON Corporation:
* Lynn R. Anspaugh, University of Utah:
* Carl Paperiello, Talisman International, LLC:
* David Brenner, Columbia University: 

Discussion Group on Environmental Impacts: 

* Timothy Mousseau, University of South Carolina:
* Patricia J. Culligan, Columbia University:
* James Clarke, Vanderbilt University:
* John Quinn, Argonne National Laboratory:
* Chris G. Whipple, ENVIRON Corporation:
* Carl Paperiello, Talisman International, LLC: 

To assess the requirements that NRC places on licensees for inspecting 
underground piping systems and monitoring and reporting on leaks from 
these systems, we reviewed and analyzed relevant NRC regulations and 
requirements, and interviewed NRC officials from the Office of Nuclear 
Reactor Regulation, Office of General Counsel, Region I, and Region 
III (a map of the NRC regions is provided in figure 3). 

Figure 3: NRC Regional Offices: 

[Refer to PDF for image: illustrated U.S. map] 

The following are depicted on the map: 

Headquarters: Rockville, Maryland. 

Region I: 
Regional Office: King of Prussia, Pennsylvania. 

Region II: 
Regional Office: Atlanta, Georgia. 

Region III: 
Regional Office: Lisle, Illinois. 

Region IV: 
Regional Office: Arlington, Texas. 

Sources: NRC (data); Map Resources (map). 

[End of figure] 

To identify actions the nuclear power industry, licensees, and NRC 
have taken in response to underground piping system leaks, we 
conducted site visits at a nonprobability sample[Footnote 29] of seven 
nuclear power plants in NRC Regions I and III, which are listed in 
table 2. During the site visits, we interviewed industry officials and 
NRC resident inspectors and observed ongoing underground piping system 
mitigation activities. We selected nuclear power plants for their site 
visits to include plants that had experienced recent reported 
underground piping system leaks and a nuclear power plant that had not 
experienced a major reported leak. 

Table 2: Nuclear Power Plant Site Visits: 

Nuclear power plant: Braidwood Station; 
State: Illinois; 
NRC Region: III. 

Nuclear power plant: Dresden Nuclear Power Station; 
State: Illinois; 
NRC Region: III. 

Nuclear power plant: Indian Point Nuclear Generating Station; 
State: New York; 
NRC Region: I. 

Nuclear power plant: Oyster Creek Nuclear Generating Station; 
State: New Jersey; 
NRC Region: I. 

Nuclear power plant: Pilgrim Nuclear Power Station; 
State: Massachusetts; 
NRC Region: I. 

Nuclear power plant: Seabrook Station; 
State: New Hampshire; 
NRC Region: I. 

Nuclear power plant: Vermont Yankee Nuclear Power Station; 
State: Vermont; 
NRC Region: I. 

Source: GAO. 

[End of table] 

In addition, we gathered and reviewed relevant documents from NRC, 
including NRC task force reports, policy papers, and an action plan; 
and industry, including documentation of industry initiatives. 

Finally, to determine, according to key stakeholders, what additional 
NRC requirements, if any, could help prevent and detect leaks from 
underground piping systems, we identified and interviewed over 30 key 
stakeholders using a standard set of questions. To ensure a balanced 
range of perspectives, we selected stakeholders from the following 
organizations: 

* independent consultants and experts; 

* advocacy and other interested groups, including Beyond Nuclear, 
Riverkeeper, Pilgrim Watch, and Union of Concerned Scientists; 

* industry and industry groups, including licensees at the nuclear 
power plants that we visited, the Nuclear Energy Institute, and the 
Electric Power Research Institute; 

* standards-setting organizations, including the American Society of 
Mechanical Engineers, and NACE International; 

* NRC, including officials from Headquarters, Region I, and Region III; 

* other federal and state agencies that have worked on issues related 
to underground piping system leaks and associated groundwater 
contamination. 

We identified stakeholders by performing an Internet and literature 
search for individuals and organizations that have published relevant 
reports and studies and by asking previously identified stakeholders 
for referrals. 

[End of section] 

Appendix II: Case Studies for Experts' Consideration: 

We worked with the National Academy of Sciences to convene groups of 
experts to discuss the impacts that underground piping system leaks 
have had on public health and the environment. We asked the experts to 
consider these impacts in the context of three case studies of nuclear 
power plants that recently experienced leaks from underground piping 
systems. Prior to the January 2011 discussion groups, the National 
Academy of Sciences sent the experts information packets that we 
prepared using NRC and licensee reports to provide background 
information on these three case studies. This appendix contains 
excerpts of these case study information packets, excluding their 
attachments. 

Case Study Introduction: 

We and the National Academy of Sciences are convening expert 
discussion groups on (1) the public health risks resulting from 
underground piping system leaks at nuclear power plants and (2) the 
environmental impacts resulting from underground piping system leaks 
at nuclear power plants and a plenary session on the overall 
characterization of leak impacts and further information needs. We 
would like to obtain the following information from each of the 
discussion groups: 

Public Health Risks Discussion Group: 

Information desired: 

* the impacts to public health from selected leak case studies, and: 

* the potential impacts to public health if everything in the case 
study remained the same, but the tritium concentrations were higher. 

Proposed questions for the experts: 

1. What is the risk (or risk range) associated with the levels of 
tritium detected in groundwater at select nuclear power plants if the 
groundwater was to be used for drinking water (see attached case study 
information packets)? Please describe the assumptions used and the 
sensitivity of the risk to these assumptions. 

2. How would the risk change if the tritium concentrations were twice 
the maximum concentration listed above? How would they change if the 
concentrations were an order of magnitude greater? 

3. What additional exposure pathways (other than groundwater) could 
impact the overall health risk posed to the public by tritium and 
other radionuclides released into the environment from the leaks 
(e.g., Cesium-137, Strontium-90)? 

Environmental Resource Impacts Discussion Group: 

Information desired: 

* the impacts on environmental resources from select leak case 
studies, and: 

* the potential impacts to environmental resources if everything in 
the case studies remained the same, but the tritium concentrations 
were higher. 

Proposed questions for the experts: 

1. To what extent have selected leaks from nuclear power plants 
degraded environmental resources, both on-site and off-site, in a 
manner that compromises their quality or limits their present or 
future value or use (see attached case study information packets)? 

2. How would the environmental resource impacts change if the 
contaminant concentrations were twice the concentrations in the 
examples above? How would they change if the concentrations were an 
order of magnitude greater? 

3. If leaks of similar magnitudes were to occur at other plants, what 
factors might affect the extent of the resultant environmental impacts 
or make a particular site more vulnerable to impacts? 

Plenary: 

Information desired: 

* the overall characterization of public health and environmental 
impacts from leaks, including considerations for cumulative and long- 
term impacts, 

* ability to fully characterize impacts based on the information 
available from NRC, and: 

* the additional information that would be required to fully 
characterize and assess impacts to public health and environmental 
resources. 

We selected three case study nuclear power plants for the experts' 
consideration: Braidwood, Oyster Creek, and Vermont Yankee. Each of 
these plants has had a recent underground piping system leak that 
generated public interest. In addition, the case studies represent 
some of the highest groundwater tritium concentrations detected at 
nuclear power plants in association with underground piping system 
leaks. Summary information about each of the case studies is presented 
in table 3. 

Table 3: Summary of Underground Piping System Leak Case Studies: 

Nuclear power plant (state): Braidwood (IL); 
Reactor type: PWR; 
Year operations began: 1988; 
Maximum detected/reported on-site groundwater tritium concentration: 
282,000 pCi/L; 
Maximum detected/reported off-site groundwater tritium concentration: 
1,600 pCi/L. 

Nuclear power plant (state): Oyster Creek (NJ); 
Reactor type: BWR; 
Year operations began: 1969; 
Maximum detected/reported on-site groundwater tritium concentration: 
4,500,000 pCi/L; 
Maximum detected/reported off-site groundwater tritium concentration: 
None. 

Nuclear power plant (state): Vermont Yankee (VT); 
Reactor type: BWR; 
Year operations began: 1972; 
Maximum detected/reported on-site groundwater tritium concentration: 
2,500,000 pCi/L; 
Maximum detected/reported off-site groundwater tritium concentration: 
None. 

Legend: BWR = Boiling Water Reactor; PWR = Pressurized Water Reactor: 

Source: GAO table based on NRC data. 

[End of table] 

For each of the case studies, we compiled case study information 
packets for the panelists that include information on the case study 
nuclear power plant location and area demographics; a description of 
the environment near the plant; and information about each of the 
radioactive leaks, including groundwater tritium concentrations and 
dose assessment results. 

Case Study 1: Braidwood Generating Station: 

The following information was compiled from NRC reports, licensee- 
prepared reports to NRC, and Exelon's "Tritium Project" Web site. 

Site Location and Demographics: 

Braidwood Generating Station (see figure 4)--which consists of two 
pressurized water reactors owned and operated by Exelon Nuclear--is 
located in Braceville, Illinois, and covers approximately 4,457 acres 
of land with a 2,537-acre cooling lake. More broadly, the site is 
situated in Will County, Illinois, about 20 miles southwest of Joliet, 
Illinois, and 60 miles southwest of Chicago. In 2009, approximately 
685,000 people resided in Will County's 837 square miles, resulting in 
density of 600 persons/square mile. 

Figure 4: Braidwood Generating Station: 

[Refer to PDF for image: photograph] 

Source: NRC. 

Note: This photograph was not included in the information packet sent 
to the experts. 

[End of figure] 

Description of the Environment near Braidwood Station: 

Attachment A,[Footnote 30] which is an excerpt from a hydrogeologic 
investigation report for Braidwood, includes a description of the 
environment near Braidwood including topography, surface water 
features, geology, hydrogeology, and groundwater flow conditions in 
the region surrounding the station. 

Surrounding Land Use: 

Land surrounding the Braidwood site falls mainly into the 
agricultural, residential, and recreational use categories. 
Residential lots surround the site to the north and to the east along 
Smiley Road and Center Street. Further to the north, there are several 
ponds or small lakes. The center of the Village of Braidwood is 
approximately 8,000 feet from the site measured from Smiley Road. To 
the northwest of the site, there are two main highways (Illinois State 
Highway 53 and Illinois Route 129) running parallel to each other with 
a railroad (Southern Pacific Railroad) between them. Within the 
southern portion of the site is the Cooling Lake that is used as a 
recreational area in the summer for boating and fishing by the 
Illinois Department of Natural Resources. 

A Land Use Survey conducted during August 2005 around the Braidwood 
Station was performed by Environmental Inc. (Midwest Labs) for Exelon 
Nuclear to comply with Braidwood Station's Offsite Dose Calculation 
Manual. The purpose of the survey was to document the nearest 
resident, milk producing animal and garden of greater than 500 ft2 in 
each of the sixteen 22½ degree sectors around the site. The results of 
this survey are summarized in table 4. 

Table 4: Braidwood Land Use Survey Results: 

Distance in miles from the Braidwood Station reactor buildings: 

Sector: N; 
Residence miles: 0.5; 
Livestock miles: 2.6; 
Milk farm miles: None. 

Sector: NNE; 
Residence miles: 1.8; 
Livestock miles: None; 
Milk farm miles: None. 

Sector: NE; 
Residence miles: 0.7; 
Livestock miles: 0.9; 
Milk farm miles: None. 

Sector: ENE; 
Residence miles: 0.8; 
Livestock miles: 3.3; 
Milk farm miles: None. 

Sector: E; 
Residence miles: 0.8; 
Livestock miles: 2.3; 
Milk farm miles: None. 

Sector: ESE; 
Residence miles: 2.2; 
Livestock miles: 2.3; 
Milk farm miles: None. 

Sector: SE; 
Residence miles: 2.7; 
Livestock miles: 2.7; 
Milk farm miles: 11.2. 

Sector: SSE; 
Residence miles: 4.5; 
Livestock miles: 4.1; 
Milk farm miles: None. 

Sector: S; 
Residence miles: 4.2; 
Livestock miles: 4.8; 
Milk farm miles: None. 

Sector: SSW; 
Residence miles: 1.3; 
Livestock miles: 5.3; 
Milk farm miles: 5.6. 

Sector: SW; 
Residence miles: 0.4; 
Livestock miles: 1.2; 
Milk farm miles: None. 

Sector: WSW; 
Residence miles: 0.5; 
Livestock miles: 3.8; 
Milk farm miles: None. 

Sector: W; 
Residence miles: 0.4; 
Livestock miles: 1.6; 
Milk farm miles: 8.7. 

Sector: WNW; 
Residence miles: 0.4; 
Livestock miles: 5.4; 
Milk farm miles: None. 

Sector: NW; 
Residence miles: 0.4; 
Livestock miles: None; 
Milk farm miles: None. 

Sector: NNW; 
Residence miles: 0.4; 
Livestock miles: None; 
Milk farm miles: None. 

Source: Exelon (from NRC). 

[End of table] 

Underground Piping System Leaks: 

During March 2005, the licensee was notified by the Illinois 
Environmental Protection Agency of reports of tritium in wells in a 
nearby community. Following that notification, the licensee began 
monitoring groundwater between the community and Braidwood Station and 
obtained samples from a drainage ditch that was near the community. 
While no contaminated groundwater was identified, the licensee did 
measure levels of tritium in the drainage ditch near the Braidwood 
access road. The licensee performed additional monitoring to identify 
the source of that tritium contamination. 

Between March 2005 and March 2006, the licensee sampled the wells of 
several homeowners with drinking water wells and installed groundwater 
monitoring wells to determine the extent of the tritium contamination. 
On November 30, 2005, the NRC Region III office was notified that the 
licensee had measured tritium levels as high as 58,000 picocuries per 
liter (pCi/L) in shallow, groundwater monitoring wells located at the 
northern edge of the owner-controlled area. 

The licensee attributed the contamination to historical leakage of 
vacuum breakers along the circulating water blowdown line that is 
routinely used for radioactive liquid releases to the Kankakee River. 
As an immediate corrective action, the licensee suspended all further 
releases of liquid radioactive material, while the licensee performed 
a more comprehensive evaluation of the incidents. 

Beginning in December 2005, the NRC performed an independent analysis 
of split samples taken from some of the licensee's monitoring wells 
and collected independent samples from some residents nearest to the 
site boundary. The NRC sample results were consistent with the 
licensee's results. 

The licensee identified tritium levels between 1,400 and 1,600 pCi/L 
in one residential drinking water well. The tritium levels detected in 
that well were below the Environmental Protection Agency (EPA) 
drinking water standard of 20,000 pCi/L. The tritium levels also 
corresponded to calculated doses that are well below the corresponding 
NRC dose limits. The remaining residential well samples had no 
measurable tritium above normal background levels. However, the 
licensee's monitoring identified an area of contaminated groundwater 
that extended about 2,000 to 2,500 feet north of the site boundary. 
Initial measurements by the licensee and independent measurements by 
the NRC confirmed that gamma-emitting radionuclides and Strontium-90 
(Sr-90) were not detected in the contaminated groundwater. 

NRC inspectors reviewed the origin of the tritium contamination with 
the licensee's staff. Based on the information presented and the 
licensee's measurements, the inspectors confirmed that the measured 
levels of tritium in the environment were consistent with past leakage 
of the vacuum breakers on the circulating water blowdown line. That 
line normally carried nonradioactive water back to the Kankakee River 
but also served as a dilution pathway for planned liquid radioactive 
releases. The line was about 5 miles long and contained 11 vacuum 
breakers that compensated for pressure transients within the line from 
liquid surges. A map of the blowdown line is included in Attachment B. 
[Footnote 31] 

The licensee's investigation identified that significant unplanned 
radioactive releases from three of these vacuum breakers during 1996, 
1998, and 2000 and other minor releases between 1996 and 2005 entered 
the groundwater system. The 1996 event resulted in the leakage of an 
estimated 250,000 gallons of water. The 1998 and 2000 events each 
resulted in a leakage of an estimated 3,000,000 gallons of water. Each 
leak from a vacuum breaker occurred over a period coincident with 
ongoing, liquid radioactive releases through the blowdown line. NRC 
inspectors reviewed the licensee's effluent release documents for the 
time periods described above and confirmed that the intended releases 
would have met NRC requirements if the releases had been made to the 
Kankakee River. 

The inspectors reviewed the licensee's radiological monitoring and 
assessments performed during March 2005 through March 2006, to 
characterize the extent of groundwater contamination from blowdown 
line vacuum breaker leakage. Specifically, the inspectors reviewed: 
(1) the licensee's characterization report, which documented the local 
hydrogeology around the facility through the installation of 
groundwater monitoring wells on licensee-owned property around the 
blowdown line; (2) the licensee's sampling and analysis program, which 
included groundwater and drinking water samples from private wells 
near the blowdown line; and (3) the licensee's evaluation of blowdown 
line integrity, which included acoustical monitoring of the line. The 
inspectors compared the licensee's results to the independent analysis 
performed by the NRC's contract laboratory to evaluate the accuracy of 
the licensee's measurements (see Attachment C).[Footnote 32] 

NRC inspectors independently estimated the extent and magnitude of the 
groundwater tritium contamination through NRC's contract analysis of 
water samples collected from residential drinking wells near the 
facility and from shallow monitoring wells installed by the licensee. 
The NRC's contract laboratory analyzed the samples for tritium 
contamination. In addition, the NRC's contract laboratory analyzed 
selected samples for other radionuclides using gamma spectroscopy, and 
analyses have also been performed for Sr-90 and Technetium-99 (Tc-99). 
The contract laboratory also utilized special techniques to identify 
"difficult to detect" radionuclides, such as Iron-55 (Fe-55), Nickel-
63 (Ni-63), and transuranic elements. 

The NRC's results confirmed that tritium was present in one off-site 
residential well at levels of about 1,300 to 1,500 pCi/L, which is a 
small fraction of the EPA drinking water standard of 20,000 pCi/L. In 
all other residential wells, no measurable levels of tritium or other 
licensed radioactive material above normal background have been 
detected. In a deeper on-site groundwater well, the NRC measured 
tritium as high as 282,000 pCi/L. Measurable levels of tritium have 
been found off-site in shallow monitoring wells and in a pond located 
near the plant boundary (see Attachment B). 

Estimated Off-site Radiation Doses: 

Exelon released a report in March 2006 that assessed the potential off-
site radiation doses that could have been received by members of the 
public from exposure to tritium that reached the off-site environment 
around the Braidwood Station following the blowdown line releases. The 
following paragraphs summarize the results of this study, which is 
included in its entirety in Attachment D.[Footnote 33] 

Conservative exposure scenarios were evaluated to develop bounding 
dose estimates--the highest reasonable radiation doses that could have 
been received by members of the public. These conservative scenarios 
were then evaluated in more detail to develop realistic estimates of 
dose. The methodology of NRC Regulatory Guide 1.109 was used as the 
basis for estimating doses from all scenarios. 

The estimated bounding dose to a member of the public was about 0.16 
millirem per year (mrem/yr) from ingestion of drinking water from a 
residential groundwater well containing tritium from a vacuum breaker 
release. The highest realistic estimates of radiation dose were from 
the same drinking water scenario. The estimated maximum realistic dose 
was 0.068 mrem/yr with an average or expected value about one-half 
that or 0.034 mrem/yr. When doses from the realistic exposure 
scenarios were summed, the maximum dose was estimated to be 0.072 
mrem/yr. Table 5 lists these dose estimates. 

The estimated doses from the vacuum breaker releases at the Braidwood 
Station are well below the design objective of 6 mrem/yr for the two- 
unit site provided in Title 10 of the Code of Federal Regulations Part 
50 (10 C.F.R. 50, Appendix I). The doses are even further below the 
100 mrem/yr regulatory dose limit for a member of the public provided 
in 10 C.F.R. 20, Subpart D. The estimated radiation dose represents a 
negligible increased risk--less than 0.1 percent of the risk from 
natural background radiation--to members of the public. 

Table 5: Doses to the Public from Vacuum Breaker Releases (mrem/yr): 

Exposure scenario: Drinking well water (2 adults); 
Minimum: ~0; 
Average (expected): 0.034[A]; 
Maximum: 0.068[B]. 

Exposure scenario: Eating fish from Exelon Pond (multiple individuals); 
Minimum: 0; 
Average (expected): 0.0011; 
Maximum: 0.0034. 

Exposure scenario: Maximum individual summed dose; 
Minimum: ~0; 
Average (expected): <0.04; 
Maximum: <0.072. 

Source: Exelon (from NRC). 

[A] Based on average individual drinking water ingestion rate of 370 
liters per year (L/yr). 

[B] Based on maximum individual drinking water ingestion rate of 730 
L/yr. 

[End of table] 

Site Groundwater Contamination: 

Attachment B includes maps created by Exelon that illustrate the 
groundwater tritium plumes at Braidwood from 2006 through 2010. 
Attachment E[Footnote 34] from Braidwood's 2009 Environmental Report 
to NRC provides more recent diagrams of groundwater sampling locations 
and sample results for tritium and Sr-90. 

Sources: 

Hydrogeologic Investigation Report, Braidwood Generating Station, 
September 2006: 

Tritium Investigation, Braidwood Station, March 2006: 

Braidwood 2005 Radioactive Effluent Release Report: 

Braidwood 2005 Annual Radiological Environmental Operating Report: 

Braidwood 2009 Annual Radiological Environmental Operating Report: 

NRC Inspection Report for Braidwood May 25, 2006: 

Frequently Asked Questions Regarding Clean-Up Efforts at Braidwood: 

[hyperlink, 
http://www.exeloncorp.com/PowerPlants/braidwood/tritiumproject/resources
.aspx]: 

U.S. Census Bureau, State and County QuickFacts, Will County, Illinois 
[hyperlink, http://quickfacts.census.gov/qfd/states/17/17197.html]: 

Case Study 2: Oyster Creek Generating Station: 

The following information was compiled from NRC reports, licensee- 
prepared reports to NRC, and Exelon's "Tritium Project" Web site. 

Site Location and Demographics: 

The Oyster Creek Generating Station (OCGS) (see figure 5), consisting 
of one boiling water reactor owned and operated by Exelon, is located 
on the Atlantic Coastal Plain Physiographic Province in Ocean County, 
New Jersey, about 60 miles south of Newark, 9 miles south of Toms 
River, and 35 miles north of Atlantic City. As illustrated in figure 
6, the site, covering approximately 781 acres, is situated partly in 
Lacey Township and, to a lesser extent, in Ocean Township. Access is 
provided by U.S. Route 9, passing through the site and separating a 
637-acre eastern portion from the balance of the property west of the 
highway. The station is about one-quarter mile west of the highway and 
1¼ miles east of the Garden State Parkway. The site property extends 
about 2½ miles inland from the bay; the maximum width in the north-
south direction is almost 1 mile (see figure 7). The site location is 
part of the New Jersey shore area with its relatively flat topography 
and extensive freshwater and saltwater marshlands. The South Branch of 
Forked River runs across the northern side of the site, and Oyster 
Creek partly borders the southern side. 

Figure 5: Oyster Creek Generating Station: 

[Refer to PDF for image: photograph] 

Source: NRC. 

Note: This photograph was not included in the information packet sent 
to the experts. 

[End of figure] 

Figure 6: Location of Oyster Creek Generating Station: 

[Refer to PDF for image: illustrated map] 

Map indicates the location of Oyster Creek Generating Station as well 
as a six-mile radius around the plant. 

Source: AmerGen (from NRC). 

[End of figure] 

Figure 7: Oyster Creek Generating Station Site Boundary: 

[Refer to PDF for image: illustrated map] 

Map indicates the site boundary of Oyster Creek Generating Station as 
well the site boundary of the adjacent First Energy property. 

Source: AmerGen (from NRC). 

[End of figure] 

In 2000, 434,476 people were living within 20 miles of OCGS, resulting 
in a density of 610 persons per square mile (persons/mi2). At the same 
time, 4,243,462 persons were living within 50 miles of the plant, for 
a density of 1,132 persons/mi.2 Land use in the Ocean County is 
primarily forest (45 percent of total land area), recreation (16 
percent), and government (16 percent), with a smaller land area 
occupied by residential (7 percent), industrial (3 percent), and 
commercial land uses (1 percent). 

Description of the Environment Near Oyster Creek Generating Station: 

The Generic Environmental Impact Statement for OCGS submitted by NRC 
as a part of license renewal contains a detailed description of the 
environment near Oyster Creek Generating Station. An excerpt of this 
report is enclosed in Attachment A.[Footnote 35] Aspects of the 
environment that are described in this excerpt include land use, water 
use, water quality, air quality, aquatic resources, and terrestrial 
resources. 

Surrounding Land Use: 

A Land Use Survey was conducted during 2009 around OCGS. The purpose 
of the survey was, in part, to determine the location of animals 
producing milk for human consumption in each of the 16 meteorological 
sectors out to a distance of 5 miles from the OCGS. None were 
observed. Another purpose of the survey was to determine the location 
of gardens greater than 500 square feet in size producing broad leaf 
vegetation, as well as the closest residence within each of the 16 
meteorological sectors. The distance and direction of all locations 
from the OCGS Reactor Building were determined using Global 
Positioning System technology. The results of this survey are 
summarized below. 

Table 6: Oyster Creek Generating Station Land Use Survey Results: 

Distance in miles from the OCGS reactor building: 

Sector: N; 
Residence (miles): 1.1; 
Garden[A] (miles): 2.2. 

Sector: NNE; 
Residence (miles): 0.6; 
Garden[A] (miles): 1.8. 

Sector: NE; 
Residence (miles): 0.7; 
Garden[A] (miles): 1.0. 

Sector: ENE; 
Residence (miles): 1.1; 
Garden[A] (miles): 1.2. 

Sector: E; 
Residence (miles): 1.2; 
Garden[A] (miles): None. 

Sector: ESE; 
Residence (miles): 0.7; 
Garden[A] (miles): 0.4. 

Sector: SE; 
Residence (miles): 0.6; 
Garden[A] (miles): 0.4. 

Sector: SSE; 
Residence (miles): 0.9; 
Garden[A] (miles): 1.0. 

Sector: S; 
Residence (miles): 1.6; 
Garden[A] (miles): 1.7. 

Sector: SSW; 
Residence (miles): 1.7; 
Garden[A] (miles): 4.3. 

Sector: SW; 
Residence (miles): 1.7; 
Garden[A] (miles): None. 

Sector: WSW; 
Residence (miles): 2.0; 
Garden[A] (miles): None. 

Sector: W; 
Residence (miles): None; 
Garden[A] (miles): None. 

Sector: WNW; 
Residence (miles): None; 
Garden[A] (miles): None. 

Sector: NW; 
Residence (miles): 5.3; 
Garden[A] (miles): None. 

Sector: NNW; 
Residence (miles): 1.5; 
Garden[A] (miles): 2.3. 

Source: Exelon (from NRC). 

[A] Greater than 500 ft2 in size producing broad leaf vegetation. 

[End of table] 

Underground Piping System Leaks: 

There were two underground piping system leaks at OCGS in 2009 that 
released tritiated water into the environment. The first was 
identified in April 2009, and the second was identified in August 2009. 

April 2009 Condensate Storage Tank Pipe Leak: 

On April 15, 2009, in preparation for work inside the Emergency 
Service Water (ESW) vault, water was found inside the vault. As part 
of standard practices for water removal, the water was pumped into 
drums and sampled for gamma emitters, tritium, and pH. Sample analysis 
identified tritium levels at 102,000 pCi/L. Exelon collected and 
controlled the water in the vault by pumping it (about 3,000 gallons) 
into 55-gallon drums for storage and processing. 

On April 17, 2009, Exelon received analytical results from monitoring 
well MW-15K-1A (see figure 8), which indicated a tritium concentration 
of about 4.46 million pCi/L. MW-15K-1A is located south of the ESW 
cable vault. According to Exelon, MW-15K-1A was last sampled on March 
10, 2009, as one of about 32 wells routinely sampled and analyzed as 
part of its on going groundwater monitoring program at OCGS. No 
tritium or other radionuclides, were detected in any wells above 
minimum detectable activity (MDA) at that time, including well MW-15K-
1A. Additionally, on March 25, 2009, Exelon conducted routine sampling 
of its on-site potable water sources. The results of the sample 
indicated no tritium or other radionuclides were detected in the 
potable water above MDA. 

During its investigation of the leak, Exelon installed six additional 
groundwater monitoring wells (MW-50 through 55) to support 
characterization of the tritium in the groundwater (see figure 8). 
These wells were predominately to the east of the intake structure. 

Figure 8: Oyster Creek Well Locations Associated with Buried Pipe Leak: 

[Refer to PDF for image: illustrated map] 

The map depicts the locations of the following wells: 
CST-9; 
MW-3; 
MW-4; 
MW-5; 
MW-6; 
MW-11-1A; 
MW-11-2A; 
MW-15K-1A; 
MW-50; 
MW-51; 
MW-52; 
MW-53; 
MW-54; 
MW-55. 

Source: Exelon (from NRC). 

[End of figure] 

Root Cause Analysis: 

An investigation determined that the release of tritiated water was 
caused by leaks in the 8-inch and 10-inch carbon steel Condensate 
System lines. The root cause investigation determined that the piping 
leaks developed due to a corrosion mechanism known as anodic 
dissolution. Poor application of pipe coating left the buried pipes 
susceptible to this corrosion. 

Estimated Dose to Public: 

A bounding calculation of the doses was done. A total of 66 Curies of 
tritium was assumed to be released to the discharge canal over a 4- 
month period with a dilution flow of 500,000 gallons per minute (GPM). 
The total body and organ doses were both 6.06E-04 mrem. 

In calculating doses, the licensee considered tritium as the only 
radionuclide and evaluated the following exposure pathways (and routes 
of exposure) for liquid effluents: 

* drinking water, 

* shoreline deposits, 

* ingestion of fish, and: 

* ingestion of shellfish. 

The receptors evaluated by the licensee included adults, teenagers, 
children, and infants. According to Oyster Creek's Offsite Dose 
Calculation Manual, the dose from liquid effluent is calculated to a 
person at the Route 9 bridge who consumes fish and shellfish harvested 
at that location. 

August 2009 Condensate Transfer Pipe Leak: 

On August 24, 2009, an 8-to 10-gallon per minute leak was discovered 
in the condenser bay. The leak was coming from the turbine building 
west wall penetration housing the Condensate Transfer CH-5 line, the 6-
inch Condensate Transfer Main Header. Two leaks were found in the pipe 
within the wall penetration. A tritium concentration of 1.08E+07 pCi/L 
was detected. 

Root Cause Analysis: 

The root cause investigation determined the cause of the leak to be 
galvanic corrosion of the pipe. 

Estimated Dose to the Public: 

A bounding calculation of the doses was done. A total of 2.06 Curies 
of tritium was assumed to be released to the discharge canal over a 7-
day period with a dilution flow of 1E+06 GPM. The total body and organ 
doses were both 9.36E-06 mrem (see above for a discussion of the 
radionuclides, pathways, and receptors evaluated in calculating this 
dose). 

Site Groundwater Contamination: 

The leaks have resulted in groundwater contamination at the site in 
the form of a tritium plume. Exelon's groundwater geology study 
indicates that the subsurface water flow containing the tritium plume 
under the OCGS site is contained within the shallow Cape May aquifer 
and the somewhat deeper Cohansey aquifer (see the tritium plume maps 
included in Attachment B).[Footnote 36] The tritium contamination is 
slowly moving through the subsurface to the Oyster Creek 
intake/discharge canal, where it is diluted to nondetectable levels 
and subsequently discharged into the Barnegat Bay and onward to the 
Atlantic Ocean. A layer of clay that exists between the Cohansey 
aquifer and the much deeper Kirkwood drinking water aquifer greatly 
impedes water movement downward. 

Plant-related radioactivity, including tritium, has not been detected 
at any off-site liquid discharge or groundwater environmental 
monitoring location. To date, the current on-site groundwater 
contamination condition at Oyster Creek has not exceeded any 
regulatory limits for liquid discharge releases. 

Sources: 

Exelon Corporation's Oyster Creek Tritium Project Web site: 
[hyperlink, 
http://www.exeloncorp.com/PowerPlants/oystercreek/tritiumproject/overvie
w.aspx]: 

Generic Environmental Impact Statement for License Renewal of Nuclear 
Power Plants, Regarding Oyster Creek Generating Station, January 2007: 

Oyster Creek Generating Station 2009 Annual Radiological Environmental 
Operating Report [hyperlink, http://www.nrc.gov/reactors/operating/ops-
experience/tritium/plant-info.html]: 

Oyster Creek Generating Station 2009 Radioactive Effluent Release 
Report [hyperlink, http://www.nrc.gov/reactors/operating/ops-
experience/tritium/plant-info.html]: 

Oyster Creek Generating Station Offsite Dose Calculation Manual, 
Revision 4: 

Oyster Creek Generating Station-NRC Integrated Inspection Report 
2009004: 

Oyster Creek Generating Station-NRC Inspection Report 2009008 
(Underground Piping Leak): 

NRC Correspondence to the Honorable Senator Menendez (July 19, 2010): 

Case Study 3: Vermont Yankee Nuclear Power Station: 

The following information was compiled from NRC reports, licensee- 
prepared reports to NRC, and Entergy's Web site. 

Site Location and Demographics: 

The Vermont Yankee Nuclear Power Station (VYNPS), consisting of one 
boiling water reactor owned and operated by Entergy, is located in the 
town of Vernon, Vermont, in Windham County on the west shore of the 
Connecticut River immediately upstream of the Vernon Hydroelectric 
Station and dam (see figure 9). The 125-acre site, about 1 mile wide, 
is owned by Entergy Nuclear Vermont Yankee, LLC, and is situated on 
the west shore of the Connecticut River across from Hinsdale, New 
Hampshire, on the east side of the river. The property bounding the 
site to the north, south, and west is privately owned. VYNPS controls 
the river water between the northern and southern boundary fences 
extending out to the state border near the middle of the river. The 
site is located on Vernon Pond, formed by Vernon Dam and Hydroelectric 
Station located immediately downstream 0.75 miles from the VYNPS site. 
VYNPS employs a General Electric boiling water reactor nuclear steam 
supply system licensed to generate 1593 megawatts-thermal (MWt). The 
current facility operating license for VYNPS expires at midnight, 
March 21, 2012. The principal structures at VYNPS include a reactor 
building, primary containment, control building, radwaste building, 
intake structure, turbine building, cooling towers, and main stack. 
Entergy, with approval by the Vermont Public Service Board, is 
developing an independent spent fuel storage installation for dry cask 
storage using approximately 1 acre of site land to the north of the 
plant. 

Figure 9: General Location of Vermont Yankee Nuclear Power Station: 

[Refer to PDF for image: illustrated map] 

Map depicts the location of the Vermont Yankee Nuclear Power Station 
near Vernon, Vermont, as well as a six-mile radius around the station. 

Source: Entergy (from NRC). 

[End of figure] 

Figure 10: Site Location Photo of Vermont Yankee Nuclear Power Station: 

[Refer to PDF for image: photograph] 

Source: NRC. 

Note: This photograph differs from the photograph of VYNPS that was 
included in the information packet sent to the experts. 

[End of figure] 

Description of the Environment near Vermont Yankee Nuclear Power 
Station: 

The Generic Environmental Impact Statement for VYNPS submitted by NRC 
as a part of license renewal contains a detailed description of the 
environment near VYNPS. An excerpt of this report is enclosed in 
Attachment A.[Footnote 37] Aspects of the environment that are 
described in this excerpt include land use, water use, water quality, 
air quality, aquatic resources, and terrestrial resources. A brief 
description of a few of these characteristics is also summarized below. 

Water Use: 

VYNPS does not use public water supplies for plant operations but 
instead relies on surface water from the Connecticut River and 
groundwater from on-site potable wells. The VYNPS is located on the 
west bank of Vernon Pool on the Connecticut River, about 0.75 mile 
upstream of the Vernon Hydroelectric Dam (Vernon Dam). Vernon Pool is 
the impounded portion of the Connecticut River directly upstream of 
the dam; it is both the source and receiving water body for the 
plant's cooling system. The pond covers 2,250 acres when full, and it 
is about a half-mile wide with a maximum depth of about 40 feet. The 
Connecticut River has an average daily flow of 10,500 cubic feet per 
second (cfs) at Vernon Dam. The Vernon Dam, owned and operated by 
TransCanada, regulates the river discharge to maintain a minimum 
sustained flow of 1,250 cfs, although under severe drought conditions, 
flow rates may drop below 1,250 cfs. There are a total of nine 
hydroelectric dams and three storage dams on the main stem of the 
Connecticut River upstream of the dam and three hydroelectric dams and 
one pumped-storage facility downstream of the dam. 

Cooling Water: 

The VYNPS withdraws water daily for its variable cooling system from 
Vernon Pool on the Connecticut River. Cooling water can be circulated 
through the system in one of three modes of operation: open-cycle 
(also called once-through cooling), closed-cycle, or a combination 
hybrid cycle. The plant has the highest water usage in the open-cycle 
mode of operation, withdrawing up to 360,000 GPM (802 cfs) from Vernon 
Pond. In the closed cycle mode, the rate of water pumped is reduced to 
about 10,000 GPM (22 cfs). The rate of water withdrawn from Vernon 
Pool in the hybrid-cycle mode falls between that of the open-and 
closed-cycle modes. 

Groundwater: 

In the vicinity of the major plant structures, groundwater is 
approximately 20 feet below ground surface. An inventory of potential 
sources of groundwater contamination within the source protection area 
(defined as a 500-ft radius) of each potable water supply well at the 
VYNPS is provided in source water protection plans for each well. The 
protection plans delineate management practices to reduce the 
potential risk of contamination of these wells and outline emergency 
response protocols for spills or other contamination events occurring 
within the source protection area. 

Surface Water: 

The Vermont Water Resources Board classifies the Connecticut River at 
the station's point of discharge as Class B water. Class B waters are 
managed to achieve and maintain a level of quality that supports 
aquatic biota, wildlife, and aquatic habitat; have aesthetic value; 
and are suitable for public water supply with filtration and 
disinfection, for swimming and other water-based recreation, and for 
crop irrigation and other agricultural uses. Surface water quality is 
regulated through the EPA's National Pollutant Discharge Elimination 
System (NPDES) permit program. The State of Vermont has been delegated 
responsibility by the EPA for administration of the NPDES program in 
Vermont. In addition to the water quality parameters, the plant is 
also required to monitor the following: 

* river flow rates on an hourly basis at Vernon Dam, 

* temperatures on an hourly basis at River Monitoring Station 3 (0.65 
mile downstream of the dam) and River Monitoring Station 7 (4 miles 
upstream of the plant), and: 

* concentrations of three metals (copper, iron, and zinc) via monthly 
grab samples. 

Terrestrial Resources: 

About 35 acres (28 percent) of the VYNPS site currently is occupied by 
buildings and structures. Prior to construction of the station, the 
site was primarily pasture land with a few mature trees. The remainder 
of the site supports mowed grass and early successional habitat (66 
acres; 53 percent), mixed deciduous and coniferous woodland (20 acres; 
16 percent), shrubland (3 acres; 2 percent), and wetland (1 acre; 1 
percent). In 2000, 153,409 people were living within 20 miles of 
VYNPS, for a density of 122 persons per square mile. At the same time, 
there were 1,513,282 persons living within 50 miles of the plant, for 
a density of 193 persons per square mile. 

Surrounding Land Use: 

The area within a 5-mile radius of the plant is predominantly rural 
with the exception of a portion of the town of Brattleboro, Vermont, 
and the town of Hinsdale, New Hampshire. Between 75 and 80 percent of 
the area within 5 miles of the station is wooded. The remainder is 
occupied by farms and small industries. Downstream of the plant on the 
Connecticut River is the Vernon Hydroelectric Station. 

The VYNPS Offsite Dose Calculation Manual requires that a Land Use 
Census be conducted annually between the dates of June 1 and October 
1. The census identifies the locations of the nearest milk animal and 
the nearest residence in each of the 16 meteorological sectors within 
a distance of 5 miles of the plant. The census also identifies the 
nearest milk animal (within 3 miles of the plant) to the point of 
predicted highest annual average relative disposition values due to 
elevated releases from the plant stack in each of the three major 
meteorological sectors. The census results are included in table 7. 

Table 7: Vermont Yankee Land Use Census Results: 

2009 Land use census locations[A]: 

Sector: N; 
Nearest residence Km (miles): 1.4(0.9); 
Nearest milk animal Km (miles): n/a. 

Sector: NNE; 
Nearest residence Km (miles): 1.4(0.9); 
Nearest milk animal Km (miles): 5.5 (3.4) cows. 

Sector: NE; 
Nearest residence Km (miles): 1.3 (0.8); 
Nearest milk animal Km (miles): n/a. 

Sector: ENE; 
Nearest residence Km (miles): 1.0(0.6); 
Nearest milk animal Km (miles): n/a. 

Sector: E; 
Nearest residence Km (miles): 0.9 (0.6); 
Nearest milk animal Km (miles): n/a. 

Sector: ESE; 
Nearest residence Km (miles): 1.9(1.1); 
Nearest milk animal Km (miles): n/a. 

Sector: SE; 
Nearest residence Km (miles): 2.0(1.2); 
Nearest milk animal Km (miles): 3.6 (2.2) cows[B]. 

Sector: SSE; 
Nearest residence Km (miles): 2.1 (1.3); 
[Empty]; 
Nearest milk animal Km (miles): n/a. 

Sector: S; 
Nearest residence Km (miles): 0.6 (0.4); 
Nearest milk animal Km (miles): 2.2 (1.4) cows[B]. 

Sector: SSW; 
Nearest residence Km (miles): 0.5 (0.3); 
Nearest milk animal Km (miles): n/a. 

Sector: SW; 
Nearest residence Km (miles): 0.4(0.3); 
Nearest milk animal Km (miles): 8.2 (5.1) cows. 

Sector: WSW; 
Nearest residence Km (miles): 0.5 (0.3); 
Nearest milk animal Km (miles): n/a. 

Sector: W; 
Nearest residence Km (miles): 0.6 (0.4); 
Nearest milk animal Km (miles): 0.8 (0.5) cows. 

Sector: WNW; 
Nearest residence Km (miles): 1.1 (0.7); 
Nearest milk animal Km (miles): n/a. 

Sector: NW; 
Nearest residence Km (miles): 2.3(1.4); 
Nearest milk animal Km (miles): n/a. 

Sector: NNW; 
Nearest residence Km (miles): 1.7(1.0); 
Nearest milk animal Km (miles): n/a. 

Source: Exelon (from NRC). 

[A] Sectors and distances are relative to the plant stack as 
determined by a Global Positioning System survey conducted in 1997. 

[B] Location of nearest milk animal within 3 miles of the plant to the 
point of predicted highest annual average D/Q value in each of the 
three major meteorological sectors. 

[End of table] 

Underground Piping System Leaks: 

There were two reported underground piping system leaks at VYNPS in 
2010, which released tritiated water into the environment. The leaks 
were reported on January 7, 2010, and on May 28, 2010. An 
investigation of the leaks determined the sources and Entergy 
incorporated corrective actions that included repairing the pipes, 
excavating contaminated soil, and extracting nearly 300,000 gallons of 
tritium-contaminated groundwater from the site. 

A collection of wells on-site have been used since 1988 for testing 
groundwater to show compliance with VYNPS's Indirect Discharge Permit 
from the Vermont Department of Environmental Conservation. A total of 
34 wells existed before January 2010. Many of them were used to verify 
that radioactivity and other contaminants did not pass from two 
septage spreading fields, one at the northern end of the site, and one 
at the southern end of the site. Of these 34 wells, 3 of them (GZ-1, 
GZ-3, and GZ-5) were specifically installed as part of the Nuclear 
Energy Institute's Groundwater Protection Initiative. The VYNPS 
shallow monitoring wells were drilled to a depth of about 30 feet with 
deeper monitoring wells at a depth of 60 to 70 feet. Potable water has 
traditionally been supplied to various site locations from 4 (350+ 
feet deep) on-site wells. In early 2010, as an additional safety 
precaution, use of the Construction Office Building on-site well for 
drinking water was discontinued. 

Root Cause Analysis: 

An investigation into the release of tritiated water determined the 
following two root causes: 

* inadequate construction and housekeeping practices employed when the 
Advanced Off-Gas (AOG) Building was constructed in the late 1960s and 
early 1970s, and when the AOG drain line was added in 1978, and: 

* ineffective monitoring and inspection of vulnerable structures, 
systems, and components that eventually leaked radioactive materials 
into the environment. 

Furthermore, corrosion found in two pipes in the AOG pipe tunnel was 
considered a contributing cause of the leak. The report stated that 
pipes should not fail. If pipes do fail, the contents should be 
contained and kept from the environment, and any leaks that occur 
should be identified promptly. 

Two additional identified organizational and programmatic causes 
included the fact that implementation of the Nuclear Energy Institute 
(NEI) NEI 07-07, "Industry Groundwater Protection Initiative," was not 
timely or complete, based upon: (1) Entergy's implementation of the 
NEI Industry Groundwater Protection Initiative, to date, had not 
adequately defined fleet, corporate, and VYNPS's accountabilities and 
(2) inadequate commitment by management to fully implement the NEI 
Industry Groundwater Protection Initiative. An NRC inspector noted 
that these organizational and programmatic issues involving 
groundwater monitoring were previously examined by the NRC (reference 
Inspection Report No. 05000271/2010006, dated May 20, 2010) and were 
consistent with the NRC's conclusions in that report. 

Estimated Dose to Public and Assessed Safety Significance: 

Entergy Vermont Yankee is limited to the amount of radiation exposure 
that can be received if an individual were to stand at the company's 
property boundary 24 hours a day, 365 days a year. The limit at most 
nuclear sites is 100 mrem per year at the site boundary. At VYNPS, the 
limit agreed to by Entergy Vermont Yankee and the Vermont Department 
of Health is 20 mrem per year. VYNPS and the Vermont Department of 
Health each collect surveillance data from more than 1,300 different 
measurements of the air, water, milk, soil, vegetation, sediment, and 
fish each year. 

VYNPS officials wrote a report that describes the course of their 2010 
leak events, beginning with the discovery of the tritium leak that was 
reported by them in January 2010, the search for the source or sources 
of the leak, the identification of the AOG pipe tunnel leak and the 
soil contamination that resulted as nuclear reactor water passed from 
the failed pipes, out the pipe tunnel into the soil, and then into the 
groundwater. This report was not released to the public, but the 
Vermont Department of Health summarized major points of interest from 
this report that relate to public health and environmental protection. 

According to the VYNPS report, there was "no nuclear, radiological or 
personnel safety significance." As evidence of this, it was pointed 
out that the AOG system is not safety-related and therefore the 
protection of the reactor and fuel was not jeopardized. The calculated 
dose from the methods of Vermont Yankee's Offsite Dose Calculation 
Manual was used to demonstrate the lack of radiological safety 
significance. This dose--0.00095 mrem per year--was compared to the 
NRC annual dose limit of 100 mrem per year and the EPA annual limit 
for the maximally exposed individual of 25 mrem per year, as evidence 
that there was no radiological safety significance. 

The maximally exposed member of the public for dose assessment 
purposes was considered to be a child who consumed fish from the 
Connecticut River above the Vernon Dam and consumed food products 
grown with irrigated water from the Connecticut River below the Vernon 
Dam, and consumed drinking water downstream from the Connecticut River 
below the Vernon Dam. The child was assumed to consume 6.9 kilograms 
per year (kg/yr) of fish, 520 kg/yr of vegetables, 26 kg/yr fresh 
leafy vegetables, 41 kg/yr of meat, 330 L/yr of milk, and 510 L/yr of 
drinking water. 

Site Groundwater Contamination: 

The 2010 identified leaks have resulted in groundwater contamination 
at the site in the form of a tritium plume. This condition did not 
result in any NRC regulatory limits related to effluent releases being 
exceeded. In 2010, the maximum concentration detected was 2,500,000 
pCi/L. Ongoing sample results continue to confirm that no off-site 
environmental monitoring locations contain detectable levels of plant- 
related radioactivity, including tritium. See the map of the VYNPS 
tritium plume included in Attachment B.[Footnote 38] 

Sources: 

Generic Environmental Impact Statement for License Renewal of Nuclear 
Power Plants, Regarding Vermont Yankee Nuclear Power Station, August 
2007: 

Vermont Yankee Nuclear Power Station License Renewal Application: 

Vermont Yankee Nuclear Power Station-Groundwater Monitoring Inspection 
Report 05000271/2010006: 

Vermont Yankee Nuclear Power Station-NRC Inspection and Review of 
Areas Identified in Demand for Information (Inspection Report 
05000271/2010007): 

Vermont Yankee Nuclear Power Station-NRC Inspection Report 05000271/ 
2010009 (Root Cause Evaluation Report of Buried Piping Leak): 

Vermont Department of Health Web site: [hyperlink, 
http://healthvermont.gov/enviro/rad/yankee/graphics.aspx]: 

Vermont Yankee Web site: [hyperlink, 
http://www.safecleanreliable.com/03252010-release.html]: 

[End of section] 

Appendix III: Comments from the Nuclear Regulatory Commission: 

United States Nuclear Regulatory Commission: 
Washington, D.C. 20555-0001: 

May 23, 2011: 

Ms. Kim Gianopoulos, Assistant Director: 
Natural Resources and Environment: 
Government Accountability Office: 
441 G Street, NW: 
Washington, D.C. 20548: 

Dear Ms. Gianopoulos: 

I would like to thank you for the opportunity to review and submit 
comments on the April 2011 draft of the U.S. Government Accountability 
Office (GAO) report, "Oversight of Underground Piping Systems 
Commensurate with Risk, but Proactive Measures Could Help Address 
Future Leaks." 

In general the U.S. Nuclear Regulatory Commission (NRC) agrees with 
the draft GAO report and believes it to be fair and balanced. The NRC 
also agrees with each of the report recommendations and has already 
established activities to address them. In particular, the report 
recommends that the agency staff "periodically evaluate the extent to 
which the industry's voluntary Groundwater Protection Initiative will 
result in prompt detection of leaks and, based upon these evaluations. 
determine whether the agency should expand its groundwater monitoring 
requirements." The NRC routinely inspects nuclear power plant 
licensees using NRC Inspection Procedure 71124.06, "Radioactive 
Gaseous and Liquid Effluent Treatment," dated December 2, 2009. This 
procedure requires the NRC to inspect licensee Groundwater Protection 
Initiative Programs by reviewing reported groundwater monitoring 
results and changes to the licensee's written program for identifying 
and controlling contaminated spills or leaks to groundwater. The 
public can be assured that the NRC will continue to review the status 
of industry implementation of the initiative and consider regulatory 
changes as appropriate. We believe these activities are in accordance 
with the GAO recommendation. 

With respect to the second recommendation, considering the compendium 
of information about degradation of buried piping and direct 
measurement on samples of buried piping. and given the industry's 
Groundwater Protection Initiative, which includes risk ranking of 
piping systems based on potential for, and consequences of, failure as 
well as follow-on inspections, the staff believes there is reasonable 
assurance that the underground piping systems will remain structurally 
sound and thus meet their licensing basis function(s). We agree with 
GAO's associated recommendation for the NRC to stay abreast of 
industry research to develop technologies and evaluate costs and 
benefits to determine whether regulatory requirements should be 
expanded. The NRC has already established milestones in the staff's 
Buried Piping Action (ML102590171) to periodically assess both the 
performance of available inspection technology and the need to make 
changes to the current regulatory framework. 

The enclosure provides specific technical comments concerning the 
NRC's plans and activities related to groundwater protection and 
buried and underground piping and tanks. 

Should you have any questions about these comments, please contact Mr. 
Jesse Arildsen of my staff at (301) 415-1785 or at 
Jesse.Arildsen@nrc.gov. 

Sincerely, 

Signed by: 
[Illegible], for: 
R.W. Borchardt: 
Executive Director For Operations: 

Enclosure: 

NRC Technical Comments Regarding GAO Draft Report, GAO-11-563. 

[End of section] 

Appendix IV: GAO Contact and Staff Acknowledgments: 

GAO Contact: 

Frank Rusco, 202-512-3841, or ruscof@gao.gov: 

Staff Acknowledgments: 

In addition to the individual named above, Kim Gianopoulos, Assistant 
Director; Nancy Crothers; Mark Gaffigan; Cindy Gilbert; Anne Hobson; 
Karen Keegan; Jonathan Kucskar; Diane Lund; Jaclyn Nidoh; and Timothy 
Persons made key contributions to this report. Joyce Evans, Jena 
Sinkfield, and Cynthia S. Taylor provided technical assistance. 

[End of section] 

Footnotes: 

[1] For the purposes of this report, the term "underground piping 
systems" includes what NRC defines as: (1) buried piping--piping that 
is underground and in contact with soil or encased in concrete and (2) 
underground piping--piping that is below the ground's surface but 
encased within a tunnel or a vault such that it is in contact with air 
and located where access for inspection is restricted. In addition, 
the term includes all piping system components, such as joints and 
valves, as some of these components have also been the source of 
reported leaks. 

[2] These violations were issued due to licensees' failure to properly 
evaluate the radiological consequences of the leaks. 

[3] Contentions are petitions filed by stakeholders during the NRC 
licensing process opposing a license application as submitted. 10 
C.F.R. Part 2 contains NRC's regulations on licensing proceedings. 

[4] Two experts served on both groups. 

[5] See appendix II for additional information on the case study power 
plant sites considered by the experts. 

[6] Results from nonprobability samples cannot be used to make 
inferences about a population because, in a nonprobability sample, 
some elements of the population being studied have no chance or an 
unknown chance of being selected as part of the sample. 

[7] Other common sources of leaks that have resulted in groundwater 
contamination include spent fuel pools, outside storage tanks--such as 
condensate storage tanks and radioactive waste storage tanks--sumps, 
and vaults. 

[8] 10 C.F.R. § 50.109(a)(1) defines a backfit as "the modification of 
or addition to systems, structures, components, or design of a 
facility; or the design approval or manufacturing license for a 
facility; or the procedures or organization required to design, 
construct or operate a facility; any of which may result from a new or 
amended provision in the Commission's regulations or the imposition of 
a regulatory staff position interpreting the Commission's regulations 
that is either new or different from a previously applicable staff 
position." 

[9] 10 C.F.R. § 50.109(a)(3). The backfit rule does not apply when NRC 
finds that regulatory action is necessary to ensure that protection of 
public health and safety is adequate. 10 C.F.R. § 50.109(a)(4). In 
addition, NRC officials told us that the backfit rule applies only to 
requirements on currently licensed facilities and that additional 
requirements can be placed on new licensees without requiring a 
backfit analysis. 

[10] The NRC obtains a copy of the licensee's Offsite Dose Calculation 
Manual, which contains the licensee's calculation methodology. 

[11] NRC's Safety Evaluation Report documenting their review and an 
Environmental Impact Statement as required under the National 
Environmental Policy Act. 

[12] A curie is a measure of radioactivity; a picocurie is one 
trillionth of a curie. 

[13] NRC and EPA use different methods to calculate radiation 
standards. 

[14] According to NRC, the half-life of tritium is approximately 12.3 
years, which means that the amount of tritium decreases by half every 
12.3 years. 

[15] NRC officials told us that the scope of inspection requirements 
has increased for plants operating beyond their original 40-year 
license. 

[16] NRC requires design, testing, and inspection for piping systems 
in accordance with applicable sections of the ASME Code. The testing 
prescribed by the code is not necessarily capable of detecting smaller 
sized leaks. 

[17] According to NRC, "plant environs" are the area within the 
perimeter of the plant site, but outside of the plant buildings and 
the reactor. 

[18] NRC requires licensees to monitor groundwater on-site if there 
have been known leaks or spills or if discharges are likely to affect 
groundwater or drinking water supplies. 

[19] These reporting requirements for licensee events are contained in 
10 C.F.R. §§ 20.2203, 50.73. 

[20] Under 10 C.F.R. § 20.2202(a), a licensee must, with few 
exceptions, notify NRC immediately of an event involving a 24-hour 
dose for which an individual present would receive an intake of five 
times the annual limit. 

[21] NEI is the policy organization of the nuclear energy and 
technologies industry. 

[22] This initiative is implemented by NEI-07-07. 

[23] This initiative is implemented by NEI-09-14. 

[24] SECY 09-0174. 

[25] According to NRC, such tests are typically called nondestructive 
examinations. 

[26] In December 2010, NRC revised its guidance for plants operating 
beyond their original 40-year license to include direct inspections of 
some piping even if it has not been excavated for another purpose. 

[27] NACE International was formerly known as the National Association 
of Corrosion Engineers. NACE International develops corrosion 
prevention and control standards for many industries from chemical 
processing and water systems to transportation and infrastructure 
protection. 

[28] Aging Management Programs for some license renewals require 
inspection of nonsafety-related floor drain piping that can 
potentially contain radioactive materials. 

[29] Results from nonprobability samples cannot be used to make 
inferences about a population because, in a nonprobability sample, 
some elements of the population being studied have no chance or an 
unknown chance of being selected as part of the sample. 

[30] Attachment A, which is not included in this appendix, was an 
excerpt from a hydrogeologic investigation report prepared for Exelon 
that included a description of the Braidwood Station. 

[31] Attachment B, which is not included in this appendix, contained 
Braidwood site maps and groundwater tritium plume maps. 

[32] Attachment C, which is not included in this appendix, contained 
Exelon's groundwater sample results and NRC's split sample results. 

[33] Attachment D, which is not included in this appendix, contained 
an assessment of the off-site doses from inadvertent releases of water 
from the blowdown line at Braidwood Station from Exelon's 2005 Annual 
Effluent Report to NRC. 

[34] Attachment E, which is not included in this appendix, contained 
Exelon's 2009 groundwater sampling reports and results for Braidwood. 

[35] Attachment A, which is not included in this appendix, contains an 
excerpt from Oyster Creek's Generic Environmental Impact Statement 
prepared for relicensing. 

[36] Appendix B, which is not included in this appendix, contained 
maps of the groundwater tritium plumes at Oyster Creek Generating 
Station. 

[37] Attachment A, which is not included in this appendix, contained 
an excerpt from VYNPS's Generic Environmental Impact Statement 
prepared for relicensing. 

[38] Attachment B, which is not included in this appendix, contained a 
map of the groundwater tritium plume at VYNPS. 

[End of section] 

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