Nuclear Regulatory Commission: Oversight of Underground Piping Systems Commensurate with Risk, but Proactive Measures Could Help Address Future Leaks
Published: 2011-06-03T00:00:00

Fast Facts:

Highlights:
section_title: Why GAO Did This Study
paragraphs: 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.
section_title: What GAO Found
paragraphs: 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 onsite 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.
section_title: What GAO Recommends
paragraphs: 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.

section_title: Letter
paragraphs: 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,  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.  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.
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,  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.  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 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.
subsections: section_title: Background
paragraphs: 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  fig. 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.
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.  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.
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” 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.
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, and NRC reviews  these calculations to verify their validity and conformance to NRC  requirements. NRC’s review and verification are documented in reports,  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). 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.
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.
section_title: 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
paragraphs: 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.
subsections: section_title: 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
paragraphs: 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.
section_title: 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
paragraphs: 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. 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.
section_title: 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
paragraphs: 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.
section_title: 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
paragraphs: 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. 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, 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”  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. 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. 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.
section_title: The Nuclear Power Industry, Licensees, and NRC Have Taken a Variety of Actions in Response to Underground Piping Leaks
paragraphs: 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), 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, 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. 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. 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.
section_title: Several Stakeholders Recommended That NRC Enhance Its Inspection, Groundwater Monitoring, and Reporting Requirements
paragraphs: 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.
subsections: section_title: Several Stakeholders Identified Enhancements NRC Could Make to Its Inspection Requirements
paragraphs: 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, 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. 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. 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, 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.
section_title: Several Stakeholders Suggested More Stringent On-site Groundwater Monitoring Requirements
paragraphs: 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.
section_title: Some Stakeholders Said That NRC Should Require More Timely Leak Information from Licensees and Should Make It More Accessible to the Public
paragraphs: 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.
section_title: Conclusions
paragraphs: 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.
section_title: Recommendations for Executive Action
paragraphs: 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.
section_title: Agency Comments and Our Evaluation
paragraphs: 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 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.
section_title: Appendix I: Objectives, Scope, and Methodology
paragraphs: 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 app. 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 fig. 3).
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 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.
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.
section_title: Appendix II: Case Studies for Experts’ Consideration
paragraphs: 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.
subsections: section_title: Case Study Introduction
paragraphs: 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:  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:  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? 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  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.
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.
section_title: Case Study 1: Braidwood Generating Station
paragraphs: The following information was compiled from NRC reports, licensee- prepared reports to NRC, and Exelon’s “Tritium Project” Web site.
subsections: section_title: Site Location and Demographics
paragraphs: Braidwood Generating Station (see fig. 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.
section_title: Description of the Environment near Braidwood Station
paragraphs: Attachment A, 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.
section_title: Surrounding Land Use
paragraphs: 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 ft in each of the  sixteen 22½ degree sectors around the site. The results of this survey are  summarized in table 4.
section_title: Underground Piping System Leaks
paragraphs: 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.
Attachment B, which is not included in this appendix, contained Braidwood site maps and  groundwater tritium plume maps. the NRC’s contract laboratory to evaluate the accuracy of the licensee’s  measurements (see Attachment C).
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).
section_title: Estimated Off-site Radiation Doses
paragraphs: 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.
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.
section_title: Site Groundwater Contamination
paragraphs: Attachment B includes maps created by Exelon that illustrate the  groundwater tritium plumes at Braidwood from 2006 through 2010.  Attachment E from Braidwood’s 2009 Environmental Report to NRC  provides more recent diagrams of groundwater sampling locations and  sample results for tritium and Sr-90.
section_title: Sources
paragraphs: 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  U.S. Census Bureau, State and County QuickFacts, Will County, Illinois  (http://quickfacts.census.gov/qfd/states/17/17197.html)
section_title: Case Study 2: Oyster Creek Generating Station
paragraphs: The following information was compiled from NRC reports, licensee- prepared reports to NRC, and Exelon’s “Tritium Project” Web site.
subsections: section_title: Site Location and Demographics
paragraphs: The Oyster Creek Generating Station (OCGS) (see fig. 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 fig.  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.
In 2000, 434,476 people were living within 20 miles of OCGS, resulting in a  density of 610 persons per square mile (persons/mi). At the same time,  4,243,462 persons were living within 50 miles of the plant, for a density of  1,132 persons/mi.
Aspects of the environment that are  described in this excerpt include land use, water use, water quality, air  quality, aquatic resources, and terrestrial resources.
section_title: Surrounding Land Use
paragraphs: 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.
section_title: Underground Piping System Leaks
paragraphs: 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.
subsections: section_title: April 2009 Condensate Storage Tank Pipe Leak
paragraphs: 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 fig. 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 fig. 8). These wells  were predominately to the east of the intake structure.
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.
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:  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.
section_title: August 2009 Condensate Transfer Pipe Leak
paragraphs: 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.
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).
section_title: Site Groundwater Contamination
paragraphs: 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). 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.
section_title: Sources
paragraphs: Exelon Corporation’s Oyster Creek Tritium Project Web site:  http://www.exeloncorp.com/PowerPlants/oystercreek/tritiumproject/overv iew.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 (http://www.nrc.gov/reactors/operating/ops- experience/tritium/plant-info.html)
Oyster Creek Generating Station 2009 Radioactive Effluent Release Report  (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)
section_title: Case Study 3: Vermont Yankee Nuclear Power Station
paragraphs: The following information was compiled from NRC reports, licensee- prepared reports to NRC, and Entergy’s Web site.
subsections: section_title: Site Location and Demographics
paragraphs: 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 fig. 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.
N.E.C.
section_title: Description of the Environment near Vermont Yankee Nuclear Power Station
paragraphs: 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. 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.
subsections: section_title: Water Use
paragraphs: 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.
section_title: Cooling Water
paragraphs: 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.
section_title: Groundwater
paragraphs: 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.
section_title: Surface Water
paragraphs: 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.
section_title: Terrestrial Resources
paragraphs: 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.
section_title: Surrounding Land Use
paragraphs: 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.
section_title: Underground Piping System Leaks
paragraphs: 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.
subsections: section_title: Root Cause Analysis
paragraphs: 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.
section_title: Estimated Dose to Public and Assessed Safety Significance
paragraphs: 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.
section_title: Site Groundwater Contamination
paragraphs: 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.
section_title: Sources
paragraphs: 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)
section_title: Appendix III: Comments from the Nuclear Regulatory Commission
section_title: Appendix IV: GAO Contact and Staff Acknowledgments
subsections: section_title: GAO Contact
section_title: Staff Acknowledgments
paragraphs: 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.