This background section describes NRC’s role and its processes for overseeing reactor safety, specifically the Reactor Oversight Process and the Traditional Enforcement Process. NRC is an independent agency of about 4,000 employees established by the Energy Reorganization Act of 1974 to license and regulate U.S. civilian—that is, commercial, industrial, academic, and medical—use of nuclear materials. NRC is headed by a five-member Commission. The President appoints these Commission members, who are confirmed by the Senate, and designates one of them to serve as the Chair and official spokesperson. NRC seeks to carry out its mission of ensuring safe operation of the 100 commercial nuclear power reactors currently operating in the United States from its headquarters office in Rockville, Maryland, its four regional offices—in King of Prussia, Pennsylvania (Region I); Atlanta, Georgia (Region II); Lisle, Illinois (Region III); and Arlington, Texas (Region IV)—and resident (on-site) inspectors’ offices located at 62 nuclear power plants in 31 states. (See fig. 1.) Appendix II provides a complete list of the commercial nuclear power reactors operating in the United States and additional information about each one. Under the Atomic Energy Act, as amended, NRC is responsible for issuing licenses to commercial nuclear reactors and conducting oversight of activities under such licenses to protect the health and safety of the public, among other things. NRC is authorized to conduct inspections and investigations, to enforce its requirements, such as by issuing orders and imposing civil (monetary) penalties, and to revoke licenses. To oversee the activities of licensed commercial reactors, NRC has established regulations, as well as guidance, including regulatory guides, standard review plans, and NRC’s Inspection Manual. These regulations and guidance, along with plant-specific licenses and technical specifications, form the basis by which NRC provides continuous oversight of reactor operations. NRC’s oversight of commercial nuclear reactors includes monitoring their performance in three strategic areas: (1) reactor safety, that is, avoiding accidents and reducing the consequences of accidents if they occur; (2) radiation safety, that is, ensuring safety from radiation for both plant workers and the public during routine operations; and (3) safeguards, that is, protecting of the plant against sabotage or other security threats. These areas comprise seven cornerstones of NRC’s oversight (see table 1). According to NRC, reactors’ satisfactory performance in these cornerstones provides reasonable assurance of safe operation. Our review focuses on NRC’s oversight of the safe operation of reactors; therefore, the physical security of plants (Physical Protection cornerstone) is outside the scope of this review. NRC also looks for systemic problems by monitoring reactors’ performance in three cross-cutting areas that extend across the cornerstones: Problem identification and resolution. The licensee (1) ensures that issues potentially affecting nuclear safety are promptly identified, fully evaluated, and addressed in a timely manner; (2) uses operating experience information to support plant safety; and (3) conducts performance assessments to identify areas for improvement. Human performance. The licensee (1) makes decisions demonstrating that nuclear safety is an overriding priority; (2) ensures that staff, equipment, procedures, and other resources are available and adequate to assure nuclear safety; (3) plans and coordinates work activities consistent with nuclear safety; and (4) uses work practices that support human performance. Safety-conscious work environment. The licensee maintains an environment in which employees feel free to raise safety concerns, both to their management and to NRC, without fear of retaliation and where such concerns are promptly reviewed, properly prioritized, and appropriately resolved. The Reactor Oversight Process (ROP) is the central component of NRC’s oversight efforts. Under the ROP, NRC undertakes four key actions: (1) reviewing key indicators of licensees’ performance; (2) physically inspecting reactors; (3) assessing whether any findings resulting from inspections are associated with any of the cross-cutting areas; and (4) determining what actions, if any, to take in response to signs of declining performance and any related violations of NRC requirements. NRC technical specialists located at its regional offices review licensee performance using quantitative measures or indicators of that performance. According to NRC documents, performance indicators are designed to illustrate a long-term view of a licensee’s performance—over multiple quarters. Currently, NRC uses 17 performance indicators it developed collaboratively with the industry to measure licensee performance. Each performance indicator is designed to help gauge a licensee’s performance within the different cornerstones outlined above. For example, a performance indicator under the “Initiating Events” cornerstone measures the number of unplanned reactor shutdowns during the previous four quarters. Appendix III provides a list of the safety-related (nonsecurity) performance indicators and related cornerstones. Each licensee voluntarily submits data quarterly for each performance indicator, and NRC measures licensee performance from these data against established numerical thresholds; assigning a color—green, white, yellow, or red—to reflect increasing risk to reactor safety based on these performance data. Specifically, a green indicator reflects performance within an expected range, but white, yellow, and red represent decreasing levels of a licensee’s performance (see table 2). Physical inspections are one of the main tools NRC uses to oversee licensee performance. During these inspections, NRC inspectors are to verify the accuracy of the quarterly data for each performance indicator supplied by the licensee and to assess aspects of licensee performance that are not directly measured by the performance indicator data—for example, confirming that fire protection equipment is in place and that certain maintenance operations have occurred. These inspections cover a wide variety of major systems and technical areas of nuclear power reactors that NRC considers most critical to meeting the overall agency mission of ensuring nuclear power plant safety. NRC currently has 52 different inspection procedures, and they are divided into three broad types of inspections—baseline (46), supplemental (3), and reactive (3)— that vary by depth and objective. Appendix IV provides a list of inspection procedures. Baseline inspections. Baseline inspections are the minimum level of inspections performed at all nuclear power reactors, regardless of performance, and are designed to detect declining safety performance in each of the cornerstones and to review licensee effectiveness at identifying and resolving safety problems. NRC resident inspectors, who are located at each plant, and regional technical specialists, who travel to each plant from NRC regional offices, conduct 46 baseline inspection procedures both as needed and at intervals ranging from quarterly to triennially, involving physical observations of licensee activities and plant performance, reviewing and verifying licensee reports, and interviewing licensee personnel. Each of the baseline procedures specifies a range of sample activities to inspect. Within the scope and requirements of each procedure, inspectors select the type and number of activities to review on the basis of factors, such as the sample activities available; their risk significance; and the amount of time since a particular system or component was last inspected. NRC assesses any issues of concern and determines whether to elevate them to a finding based on certain criteria. To determine whether an issue of concern constitutes a finding, inspectors must first decide whether it is associated with a performance deficiency, which NRC guidance defines as “an issue that is the result of a licensee not meeting a requirement or standard where the cause was reasonably within the licensee’s ability to foresee and correct, and therefore should have been prevented.” NRC guidance defines a finding as an issue of concern associated with a performance deficiency that inspectors or regional officials then determine to be more than minor. NRC then assesses—through its ROP Significance Determination Process—the finding’s risk significance. Similar to performance indicators, NRC assigns the finding one of four colors to reflect increasing risk to reactor safety. Green findings—also called nonescalated findings—equate to very low risk significance, while white, yellow, and red findings—considered to be escalated findings—represent increasing levels of risk (see table 3). Appendix V provides select examples of NRC findings and related information that illustrate the varying levels of risk significance. Supplemental inspections. When NRC identifies one or more escalated findings or a performance indicator exceeding the green threshold at a reactor, regional officials conduct supplemental inspections, which expand the scope beyond baseline inspection procedures and focus on diagnosing the cause of the finding. There are three levels of supplemental inspections that increase in breadth and depth of analysis, depending on the number and type of performance problems identified. The first and lowest level of supplemental inspection assesses the licensee’s corrective actions to ensure they were sufficient in both correcting the problem and addressing the root and contributing causes to prevent recurrence. The second level of supplemental inspection has an increased scope that includes independently assessing the extent of the condition for both the specific and any broader performance problems. The third and highest level of supplemental inspection is more comprehensive and includes determining whether the reactor can continue to operate and whether additional regulatory actions are necessary. The highest level of supplemental inspection is usually conducted by a multidisciplinary team of NRC inspectors and may take place over several months. Also, as a part of this inspection, NRC inspectors assess the adequacy of the licensee’s overall programs for identifying, evaluating, and correcting performance issues. Reactive inspections. NRC conducts reactive inspections of licensee performance when specific events occur that are of particular interest to NRC because of their potential safety significance or because of potential generic safety concerns important to multiple licensees. Reactive inspections determine the cause of the event and assess the licensee’s response to the event. Reactive inspections have three levels that are normally determined by an event’s safety, or risk significance. According to NRC officials, recent reactive inspections have focused on issues such as an automatic reactor shutdown following a loss of offsite power, and a flaw discovered in a weld on a reactor component. To conduct reactive inspections, a team of experts is formed and an inspection charter issued that describes the scope of the inspection efforts. NRC inspectors assess all of the findings that result from physical inspections to determine if any of the three cross-cutting areas contributed to a performance problem. If regional officials determine that one of the cross-cutting areas contributed to a finding, NRC assigns what it calls a cross-cutting aspect within that area to the finding. More than one cross-cutting aspect may be assigned to a finding, but this does not occur often, according to NRC officials. Every 6 months, NRC regional officials analyze all findings issued at each plant during the prior 12- month assessment period. In general, if a nuclear plant has four findings with the same cross-cutting aspect assigned during the previous year, and NRC is concerned about the licensee’s progress in addressing them, NRC determines that the nuclear plant has what NRC calls a substantive cross-cutting issue. According to NRC documents, the agency identifies substantive cross-cutting issues to inform the licensee that it has a concern with its performance and to further encourage it to take appropriate actions before more significant performance issues emerge. NRC assesses its reviews of performance indicators and all findings that result from its physical inspections to determine what actions, if any, to take in response to signs of declining performance, including violations of NRC requirements. The significance of any violations associated with a finding is incorporated into the color coded risk assessment made during the Significance Determination Process. For enforcement of violations associated with nonescalated findings, NRC establishes a public record of the violations and requires the licensee to take steps to correct the violations, but it does not usually require the licensee to document its responses. For enforcement of violations associated with escalated findings, NRC issues written notices of violation (to which licensees are typically required to respond), civil penalties, or orders. Based on NRC’s assessment of licensee performance under the ROP, NRC places each of the licensee’s reactors into one of five performance categories on its action matrix, which corresponds to graded, or increasing, levels of oversight. The action matrix is NRC’s formal method of determining how much additional oversight—mostly in the form of supplemental inspections—is required on the basis of the number and risk significance of performance indicators and inspection findings. NRC considers licensee performance to be acceptable until it reaches column 5 (see table 4). On the basis of the results of the ROP, NRC provides licensees and the public with an overall assessment of each reactor’s performance. At the end of each 6-month period, NRC issues an assessment letter to each plant to describe what level of oversight the plant’s reactors will receive according to their placement on the action matrix, what actions NRC is expecting the licensee to take as a result of the performance issues identified, any specific enforcement actions NRC has taken, and any documented substantive cross-cutting issues. If a substantive cross- cutting issue is identified, the letter will describe what actions NRC intends to take to monitor the issue. If the issue persists, NRC can request a number of actions from the licensee, including a written response describing the corrective actions the licensee intends to take. NRC also holds an annual public meeting at or near each plant to review its performance and address questions from members of the public and other interested stakeholders. Additionally, NRC has other mechanisms to make available its oversight results, such as a website that provides summaries of each reactor’s current overall performance. While it addresses most violations through the ROP, NRC also responds to some violations identified during the ROP under what it calls its Traditional Enforcement Process. NRC uses this process to assess and determine the enforcement actions, if any, to take in response to violations that, according to NRC guidance, cannot be addressed fully through the ROP. The process typically applies to violations that result in actual safety consequences, may impede NRC’s oversight of licensed activities, or involve deliberate misconduct or discrimination matters, as well as certain technical violations involving specific areas, such as operator licensing and fuel storage. The Traditional Enforcement Process, including possible civil penalties, is managed outside the ROP action matrix. The Traditional Enforcement Process focuses on a violation’s consequences and results in the assignment of a significance level ranging from Severity Level IV for the least significant to Severity Level I for the most significant concerns, according to NRC policy. NRC’s response to Severity Level IV violations is considered “nonescalated enforcement,” while its response to Severity Levels I, II, and III is considered “escalated enforcement.” In assigning a Severity Level to the violation, NRC assesses the following: (1) the actual safety consequences; (2) the potential safety consequences; (3) the potential for impacting NRC’s ability to perform its regulatory function (e.g., failure to provide complete and accurate information); and (4) any willful aspects of the violation. Severity Levels I and II violations generally involve actual or high potential consequences to public health and safety. Severity Level III violations are cause for significant concern, and Severity Level IV violations are less serious but are of more than minor concern. Appendix V provides select examples of violations that illustrate varying levels of severity. NRC includes results from the Traditional Enforcement Process in the overall semiannual assessment of each plant’s performance that it provides to plant licensees and the public. NRC relies on its staff’s professional judgment in implementing its processes, which are largely prescribed in guidance, for overseeing the safety of commercial nuclear power reactors. In implementing its oversight programs, NRC allocates specific roles and responsibilities to resident inspectors, regional staff, headquarters officials, and the nuclear power industry. NRC also provides incentives for licensees to identify and report any concerns about reactor safety to NRC. NRC oversight relies on its staff’s professional judgment in applying regulations and guidance, such as determining: (1) whether issues of concern identified in inspections constitute findings, (2) the risk significance of any findings, and (3) whether these findings have cross-cutting aspects, among other things. To implement its oversight, NRC allocates specific roles and responsibilities to regional officials, resident inspectors, headquarters officials, and the nuclear power industry. According to NRC officials, doing so allows decisions to be made at the appropriate level within the agency, but it also necessitates open communication between the various offices to effectively share information and ensure policies and processes are implemented consistently across the agency. Officials from NRC’s four regional offices are responsible for implementing the ROP and the Traditional Enforcement Process and establish—consistent with agency guidelines—the region’s procedures for assessing issues of concern and resolving most findings. According to NRC documents, the inspection program is intended to provide regional administrators flexibility with the planning and application of inspection resources to deal with risk-significant issues and problems. According to NRC officials, regional branch chiefs supervise small groups of resident inspectors, facilitate information sharing among inspectors in their region, and manage specialized teams of inspectors that conduct periodic plant inspections focused on specific technical areas, such as fire safety. Further, NRC officials said that regional branch chiefs are largely responsible for deciding whether an issue of concern raised during physical inspections constitutes a finding. Agency guidance provides them with relative autonomy in determining when an issue constitutes a more-than-minor performance deficiency. Since NRC established the ROP in 2000, regional offices have been responsible for addressing all nonescalated findings and violations, which constituted about 90 percent of findings and violations, according to our analysis of NRC data. In addition, though subject to oversight by NRC headquarters, regional offices play a lead role when assessing and responding to escalated findings or violations, including requiring licensees to provide a written response describing the reasons for a performance deficiency, actual and proposed corrective actions, and the expected date of compliance. After assessing licensee performance based, in part, on the findings or violations, regional offices then conduct supplemental inspections as appropriate, according to NRC guidance. NRC assigns resident inspectors to each nuclear power plant to conduct baseline inspections. According to NRC guidance, resident inspectors are responsible for routinely conducting plant status reviews that include observing control room activities; attending licensee meetings; and conducting walk-downs, or inspections, of various plant areas. In addition to these duties, resident inspectors are responsible for ensuring that plant representatives implement corrective actions within a “reasonable period of time” in response to nonescalated findings. NRC headquarters officials play a key role in addressing escalated findings and violations, those assigned the highest categories of risk significance or severity levels. For example, NRC officials told us that, before findings are assessed as being escalated, NRC headquarters officials participate in meetings with regional officials and resident inspectors to ensure that the assessment is accurate and any proposed enforcement actions are justifiable. Moreover, according to NRC guidance, officials in NRC headquarters must approve all enforcement actions against licensees. Specifically, this includes the Director of NRC’s Office of Enforcement, and, in certain cases, such as when responding to Severity Level I violations, the Deputy Executive Director, after consultation with the Commission. These actions can include anything from monetary penalties, to orders to take specific actions, to shutting down a plant. In addition to NRC, the commercial nuclear power industry also plays a key role to ensure that nuclear plants operate safely and comply with regulations. According to NRC policy, licensees have the primary responsibility for safely operating their plants, as well as in accordance with their licenses and NRC regulations. Each plant has many physical structures, systems, and components, and licensees have numerous activities under way 24 hours a day to ensure that plants operate safely. These plants were designed according to a “defense-in-depth” philosophy revolving around redundant, diverse, and reliable safety systems. For example, two or more key safety components are in place so that if one fails, another one is present to serve as a backup. These include safety components such as safety injection pumps, sources of power, and physical barriers to contain radiation. Furthermore, the Institute of Nuclear Power Operations (INPO)—the industry’s self-regulator—is a nonprofit organization formed in 1979 by the nuclear power industry in response to the accident at Three Mile Island. INPO has a key role in ensuring that plants operate safely by seeking to promote high levels of safety and reliability in the operation of nuclear power plants. According to its website, INPO sets performance objectives, criteria, and guidelines for the nuclear power industry, conducts evaluations of nuclear power plants, and communicates lessons learned and best practices throughout the nuclear power industry. According to INPO information, all organizations with direct responsibility to operate or construct commercial nuclear power plants in the United States have maintained continuous membership in INPO since its inception, and are primarily responsible for its funding. INPO provides a variety of services to the nuclear power industry, including personnel training for key positions at nuclear power plants, periodic evaluations and peer reviews of operating plants that are focused on plant safety and reliability, and assessments of plant performance across the industry to help licensees to understand issues that arise at other plants. According to INPO information, the organization has conducted nearly 1,200 plant evaluations, inspecting each plant approximately every 2 years, since 1980. Also, according to an INPO official, INPO uses peer pressure to influence plants to improve, and in an industry presentation, its president and chief executive officer stated that its policy of providing licensees with confidential evaluation reports allows it to have more open and candid discussions with plants about problems and areas for improvement. In addition, the industry’s collective insurance company for operational losses—Nuclear Electric Insurance Limited—uses INPO ratings as a factor in setting insurance premiums for insuring for costs associated with certain long-term interruptions of electricity supply and damages to plants, among other things. According to INPO and NRC documents, INPO and NRC communicate on topics of mutual interest related to improving the performance of commercial nuclear power plants. NRC also builds into its processes incentives for licensees to identify concerns about reactor safety, discuss those concerns with NRC, and identify actions to correct them. According to NRC guidance, these concerns—known as licensee-identified findings—include any findings the licensee is already addressing through the plants’ respective corrective action programs. If NRC’s preliminary assessment of a licensee-identified finding indicates that the finding is green, NRC does not consider it when assessing licensee performance, does not consider it to count toward substantive cross-cutting issues, and does not apply additional oversight or require additional response from the licensee. According to NRC officials, licensee-identified findings demonstrate that the licensee is taking a proactive approach and can identify and correct problems before NRC identifies them; therefore NRC gives licensees credit for identifying potential problems during their own inspection processes. Regarding licensee-identified violations, according to NRC’s enforcement policy, NRC should normally give the licensee “credit” when assessing for civil penalties—that is, the violation should be issued with no civil penalty—for identifying the violation and taking prompt and comprehensive corrective actions. On the other hand, the policy states that NRC should issue a civil penalty, regardless of whether the violation is licensee-identified, if NRC officials determine that the corrective actions have not been prompt and comprehensive. Conversely, according to its enforcement policy, NRC considers some findings and violations—whether identified by a licensee or an inspector— to be “self-revealing.” For example, according to an agency official, a licensee may discover a pool of oil on the floor next to a diesel generator, indicating that something is wrong with the equipment. NRC may consider such a finding to be self-revealing, even if the licensee identified it. Under NRC’s enforcement policy, it may give the licensee credit for such findings under certain circumstances, such as licensee effort in discovering the root cause of the finding. NRC’s oversight processes are based in regulation, and its specific processes for identifying and assessing findings and violations are largely prescribed in guidance, but rely on several key points where NRC staff must exercise their professional judgment, such as determining (1) whether an issue of concern constitutes a finding or violation, (2) a finding’s risk significance or a violation’s severity, and (3) whether findings or violations have cross-cutting aspects, among other things. According to NRC documents and officials, NRC inspectors use their professional judgment and a combination of education, experience, and prescribed agency procedures to make initial assessments as to whether an issue of concern identified during an inspection constitutes a finding. NRC officials told us that performance deficiency was defined broadly to allow officials to use their professional judgment when assessing issues of concern. If NRC inspectors determine that there is a performance deficiency, they and regional staff then determine whether the performance deficiency is more than minor. In doing so, these officials have NRC-established questions and guidance and use their professional judgment in applying them. If inspectors and regional staff determine that a performance deficiency is not more than minor, then it is not considered a finding and the matter is not pursued any further under the ROP. To help in making these determinations, inspectors can request additional information from licensees and consult NRC inspectors assigned to other nuclear plants, according to NRC officials. If resident inspectors conclude they cannot adequately assess an issue of concern, they can seek assistance from their regional office or NRC headquarters—typically from technical specialists or branch chiefs who supervise resident inspectors at two to three plants—to help make a determination. As we previously reported, inspectors also select the type and number of activities to review during inspections, in part, on the basis of an inspector’s professional judgment, which is based on information such as reviews of the licensee’s corrective action program, allegations, or interviews with plant employees. Professional judgment also plays a key role in regional officials’ determining the risk significance of a finding and the severity of a violation. If NRC determines that a performance deficiency is more than minor, it is considered a finding, and NRC regional officials assess its significance using the Significance Determination Process, which also requires the staff to exercise their professional judgment, according to NRC officials. This process provides an initial screening to identify those nonescalated findings—that is, those findings that do not result in a significant increase in plant risk and thus need not be analyzed further. Remaining findings are subjected to additional reviews to determine their risk significance, using the next phase of the Significance Determination Process—the Significance and Enforcement Review Panel (SERP). According to NRC guidance, this more detailed assessment may involve NRC risk experts from the appropriate regional office or NRC headquarters and further review by the licensee’s plant staff. The final outcome of the ROP review—evaluating whether the finding is green, white, yellow, or red—is used to determine NRC actions that may be needed. For any escalated violations identified during the ROP that are to go through the Traditional Enforcement Process, the severity level of violations is determined using a combination of NRC’s enforcement policy, professional judgment, and information obtained from the licensee during a conference with them, if necessary. NRC officials initially determine enforcement actions during an enforcement panel, and then make a final determination during a meeting, or caucus, both of which loosely correspond to the SERP. Regarding violations, NRC’s enforcement policy states that, because the regulation of nuclear activities does not lend itself to a mechanistic treatment in many cases, judgment and discretion must be exercised in determining the severity levels of violations and the appropriate enforcement sanctions. According to this policy, the use of judgment and discretion includes the decision to issue a notice of violation or to propose or impose a civil penalty and the amount of the penalty, after considering the general principles of NRC’s enforcement policy and the significance of the violation, as well as the surrounding circumstances. According to its enforcement policy, NRC may choose to exercise discretion and either escalate or mitigate enforcement sanctions or otherwise refrain from taking enforcement action within the Commission’s statutory authority. According to this policy, NRC may exercise judgment and discretion to determine the severity levels of violations and the appropriate enforcement sanctions to be taken. For example, NRC may refrain from issuing a notice of violation or a proposed civil penalty for a Severity Level II, III, or IV violation that is identified after NRC has taken enforcement action, if the violation is identified by the licensee as part of the corrective action for the previous enforcement action and the violation has the same or similar root cause as the violation for which enforcement action was previously taken, among other things. In addition, according to NRC guidance, inspectors should also use their professional judgment when assessing whether a finding is associated with any cross-cutting aspects. For example, as we reported, in analyzing the failure of a valve to operate properly at one plant, NRC inspectors determined that plant employees had not followed the correct maintenance procedures; thus, the finding was associated with the human performance cross-cutting area. Both opening and closing a substantive cross-cutting issue requires the use of professional judgment. According to NRC guidance, before opening a substantive cross-cutting issue, regional officials must determine, among other things, whether the licensee is already taking actions to address the issue and, if so, whether these actions are timely, are commensurate with its significance, and will be effective in substantially mitigating it. Once a substantive cross-cutting issue has been opened, the regional office that opened it is responsible for establishing the criteria for closing it. These criteria may include having fewer findings with the same cross-cutting area in a subsequent assessment period or the regional staff’s increased confidence in the licensee’s ability to address the substantive cross-cutting issue. The decision to close a substantive cross-cutting issue is made by regional staff, including the senior resident inspector, branch chief, and other regional management, but NRC headquarters officials told us they also participate. NRC can require licensees to take several actions to close substantive cross-cutting issues. According to NRC guidance, after first issuing a letter identifying a substantive cross-cutting issue to a licensee, NRC staff may follow up on these issues in multiple ways, including semiannual evaluations or additional inspections. In the second consecutive assessment letter identifying the same substantive cross-cutting issue, the regional office may consider requesting the licensee provide a response at a public meeting or provide a written response or hold a separate meeting. In the third consecutive letter, according to NRC guidance, the regional office would typically request that the licensee perform an independent assessment of safety culture, although the regional office could decide that a safety culture assessment is not necessary if the licensee has made reasonable progress addressing the issue. If the substantive cross-cutting issue continues beyond the third letter, the regional office may consider additional actions not prescribed by the action matrix developed in consultation with the Director of NRC’s Office of Nuclear Reactor Regulation and its Executive Director of Operations. Figure 2 outlines NRC’s processes for identifying and assessing findings and violations and key points where professional judgment plays a role. NRC is aware of differences across regions in identifying and resolving the findings that result from its oversight processes and has taken some steps to address them. In particular, the extent to which nonescalated findings, which equate to very low risk significance, have been identified differs across regions. Several factors may explain these differences, but NRC officials and industry representatives have raised concerns that they may be due, in part, to differences in how NRC staff identify and resolve findings. The four NRC regions also differed in the number of cross-cutting aspects they assigned to findings. NRC has taken some steps to address these differences but has not undertaken a comprehensive review of them. The number of escalated findings, which equate to greater risk significance, were more similar across regions. However, the information NRC makes publicly available about findings and how they are resolved is difficult to search and assess. Some regions identify more nonescalated findings than others, even though they oversee fewer reactors. For example, as table 5 indicates, from 2000 through 2012, Region IV recorded more nonescalated findings than each of the other three regions, even though it oversaw the fewest number of reactors at the fewest number of plants. During the same period, Region II—the region with the greatest number of reactors and plants—recorded the fewest number of nonescalated findings. More specifically, Region IV recorded over 70 percent more nonescalated findings than Region II even though Region IV oversaw over one-third fewer reactors; resulting in an average number of nonescalated findings per reactor for Region IV to be over 2.6 times that of Region II. As figure 3 shows, from 2000 through 2012, the number of nonescalated findings identified differed across NRC’s four regions, but Region IV recorded more nonescalated findings than any of the other three regions for 6 consecutive years—2007 through 2012. Appendix VI lists the number of nonescalated findings identified at each plant from 2000 through 2012. NRC officials stated that various factors may contribute to differences in the number of nonescalated findings identified across regions, including differences in the (1) number of hours spent inspecting reactors; (2) amount of time reactors are under increased oversight as a result of performance deficiencies; (3) age of reactors; and (4) benefits from the combined resources of multiple plants owned or managed by one licensee. Differences in inspection hours. NRC officials stated that differences in the number of hours regions spent inspecting reactors may have contributed to the differences in the number of nonescalated findings across regions, because more inspection hours would lead to more findings. However, according to 2000 through 2012 NRC data, while the total number of inspection hours has varied across the regions, the number of inspection hours has been fairly consistent across regions when accounting for the number of reactors in each region. When comparing the number of nonescalated findings in each region to the number of inspection hours and accounting for the regional differences in the number of reactors, we found that the number of nonescalated findings per inspection hour varies widely. Specifically, Region II identified the least number of nonescalated findings per inspection hour per reactor, and Region IV identified the most, with more than 3.5 times as many nonescalated findings per 1,000 inspection hours per reactor as Region II (see table 6). Differences in the amount of time reactors are under increased oversight. NRC officials stated that differences in the amount of time reactors are under increased oversight as a result of performance deficiencies— defined as being in column 2 or higher on NRC’s action matrix—may contribute to differences in the number of nonescalated findings across regions, because increased oversight results in more scrutiny and more findings. However, according to 2001 through 2012 NRC data, the number of quarters that reactors in each region were under increased oversight were fairly consistent across regions when accounting for the number of reactors in each region. When comparing the number of nonescalated findings in each region to the number of quarters that reactors in each region were under increased oversight, and accounting for the regional differences in the number of reactors, we found that the results varied widely. Specifically, Region II identified the least number of nonescalated findings per quarter under increased oversight, and Region IV recorded the most, with more than 4 times as many nonescalated findings per quarter under increased oversight as Region II (see table 7). Furthermore, Region II had more reactors under increased oversight than Region IV for 36 of the 48 quarters we reviewed. Appendix VII summarizes NRC’s performance assessments for each reactor from 2001 through 2012. Differences in the age of reactors. NRC officials stated that differences in the age of reactors may contribute to the differences in the number of nonescalated findings across regions because nonescalated findings become more prevalent as reactors age. We analyzed the age of reactors across the regions and identified regional differences in their age. However, we found that reactors in Region II, which had the fewest nonescalated findings from 2000 through 2012, have been in commercial operation, on average, more years than, and have collectively been in commercial operation for almost twice as long as, reactors in Region IV, which had the most nonescalated findings over that period (see table 8). Differences in resources available to plants. NRC officials stated that, when one licensee owns or manages multiple plants (collectively referred to as a licensee’s “fleet”), benefits derived from plants’ combined resources may contribute to the differences in the number of nonescalated findings across regions, because some regions have more plants in fleets than others. For example, according to NRC officials, licensees often require all plants that they manage or own to make improvements in response to findings made at only one of their plants, which could lead all the plants in this fleet to experience fewer findings over time. NRC officials told us that plants associated with fleets typically perform better because the licensee holds all plants to the same performance levels and provides resources and shares what would otherwise be proprietary information to make that happen. Some independent plants—those not part of a fleet—share resources by forming alliances with other plants, entering into management contracts with larger companies, or both. However, NRC officials stated that independent plants are limited in how much information they can share because some information is considered to be proprietary. We analyzed whether individual plants were associated with licensee fleets and found that being associated with a fleet may be a factor in the number of nonescalated findings a region identifies. For example, Region II, which had the fewest nonescalated findings from 2000 through 2012, had the highest percentage of its reactors located at plants associated with fleets. Conversely, Region IV, which had the most nonescalated findings during the same period, had the lowest percentage of its reactors located at plants associated with fleets (see table 9). However, because NRC has not conducted a comprehensive analysis of several potential factors, it is not clear to the extent this factor influences the differences in the number of findings across regions. In addition, NRC officials stated that the quality of reactor maintenance may contribute to the regional differences in the number of nonescalated findings. For example, the resident inspectors at a plant with a high number of findings in recent years told us that this was due, in part, to plant managers not fully addressing maintenance items for many years to save on costs. However, we could not analyze this factor because, according to NRC officials, the data are not readily available. NRC officials and industry representatives have raised concerns that differences in the number of findings NRC regions identify may be due, in part, to differences in how NRC staff identify and resolve findings. NRC officials, including some resident inspectors in Region IV, told us that they believe Region IV identifies nonescalated findings more aggressively than other regional offices and that some regional branch chiefs differently interpret the criteria for assessing performance deficiencies and what constitutes more-than-minor findings. Some NRC officials also noted that the regions have flexibility to combine issues into a single finding or to split them into multiple findings, which may also account for some of the regional variation in the number of findings identified. These officials told us that, in their view, this autonomy and discretion is a good and desirable part of the ROP. Nonetheless, in 2008, NRC’s IG reported that NRC was inconsistently resolving findings across its regional offices due, in part, to not having clear and comprehensive guidance needed to facilitate consistency. NRC officials told us they survey industry annually as part of a ROP self- assessment process and have received feedback since the implementation of the ROP in 2000 about concerns from the appearance of differences in identifying and resolving findings across regions. They also stated that the Nuclear Energy Institute—the commercial nuclear trade organization—frequently raises these concerns with them. Plant managers we interviewed—several of whom have worked at plants across different regions—also raised concerns about these apparent differences. These plant managers told us that such differences could lead to several challenges, including focusing limited plant resources on a greater number of issues of very low risk significance (i.e., nonescalated findings). NRC officials also told us that another concern that is sometimes raised about its findings by industry is that findings at different plants that appear to be similar sometimes result in different risk assessments. NRC officials provided the example of two findings at two different plants that appeared similar but that led to different assessments. Specifically, both findings dealt with problems with certain components of auxiliary feedwater pumps that rendered the pumps inoperable. Even though these findings appeared similar, they resulted in different risk significance levels—one green and one white—because they affected the safety of the two plants differently. NRC officials told us the process of assessing the risk significance of a finding is inherently complex and includes several factors, such as design of the plant, including availability of backup equipment and whether the site uses cooling towers or lakes or rivers for its ultimate source of cooling water; the effect that the finding had on the performance and availability of safety equipment; the amount of time the equipment was inoperable; criticality of the safety equipment associated with the finding; and historical reliability of the equipment in question for that plant design, among others. Once NRC accounts for these factors, similar findings may result in different assessments because the risk that a finding poses is plant- specific, according to NRC officials. The four NRC regions also differed in the number of cross-cutting aspects they assigned to findings and the percentage of findings assigned cross- cutting aspects. For example, Regions III and IV had about twice as many findings assigned at least one cross-cutting aspect as Region II (see table 10). Table 11 shows the types of cross-cutting aspects assigned to findings across regions. According to NRC guidance, identifying cross-cutting aspects is NRC’s primary means of identifying trends. The guidance states that a cross- cutting aspect is a performance characteristic of a finding that is the most significant causal factor of the performance deficiency. The guidance further states that the ROP was developed with the presumption that inspection findings with cross-cutting aspects would help them identify the plants with significant performance issues. Therefore, according to NRC officials, the greater the number of findings with cross-cutting aspects, the greater the chance that NRC could assign a substantive cross-cutting issue to the plant. Once NRC assigns a substantive cross-cutting issue to a plant, closing the issue requires additional efforts by the licensee and additional oversight from NRC. The number of plants assigned substantive cross-cutting issues at some time during calendar years 2001 through 2012 varied across the regions (see table 12). In Region II, less than half the plants were assigned a substantive cross-cutting issue, whereas a substantial majority of plants in other regions were assigned substantive cross-cutting issues. Appendix VIII summarizes the substantive cross-cutting issues assigned to plants from 2001 through 2012. According to NRC officials, because the criteria for closing a substantive cross-cutting issue involve professional judgment, determining whether to close one is somewhat subjective. The relevant regional office considers whether to close a substantive cross-cutting issue in its semiannual or annual assessment letters to licensees. Industry officials told us that, because NRC only considers closing substantive cross-cutting issues in these 6-month increments, it is difficult to close a substantive cross- cutting issue in a timely fashion. The number of escalated findings had fewer differences across regional offices. As shown in table 13, each region had between 46 and 93 escalated findings from 2000 through 2012. Region III had more Severity Level III violations than the other regions, but otherwise, the number of escalated findings was largely consistent. Appendix IX lists the number of escalated findings identified at each plant from 2000 through 2012. NRC officials told us that escalated findings are identified and addressed more consistently than nonescalated findings because they receive a much higher level of review than do nonescalated findings. For example, according to NRC’s enforcement policy, regional offices—subject to oversight by NRC headquarters—typically require licensees to provide a written response to an escalated finding that describes the reasons for the identified deficiency, actual and proposed corrective actions, and the expected date of compliance. Regional offices then conduct supplemental inspections for most escalated findings. Supplemental inspections expand the scope of baseline inspections to review, in part (1) the extent of the problem, (2) the sufficiency of the licensee’s evaluation of the root cause of the problem, and (3) the licensee’s proposed corrective actions. In addition, NRC officials told us that headquarters officials participate in meetings with regional officials and inspectors to ensure that an escalated finding is accurately assessed and that any proposed enforcement actions are justifiable. Moreover, according to NRC guidance, the Director of NRC’s Office of Enforcement (or designee)—located in headquarters— has to approve any enforcement actions against licensees in response to escalated findings. NRC has taken some steps to reduce differences across the regions in the identification and resolution of nonescalated findings but has not conducted a comprehensive analysis of the differences to determine its consistency in handling findings or reasons for the differences. A key effort NRC has undertaken to reduce differences in how the regions implement the ROP is the ROP Reliability Initiative, which NRC’s regional offices initiated in 2009. According to NRC officials, the initiative was intended to explore how the different regional offices identify and assess inspection findings. Some NRC officials said that the initiative examines issues related to consistency, such as how to control the subjectivity in making distinctions between minor and more-than-minor performance deficiencies and violations. Each region took the lead on one of the following specific efforts: Enhanced inspection resource sharing among regions: This effort was a pilot program for sharing inspection resources across regional offices. Inspectors from different regions and resident inspectors from other plants participated on several types of team inspections. This initiative was led by Region IV and began in 2009. Branch chief visits to other regions: This effort included each region designating one branch chief to visit each of the other regions to identify best practices and implementation differences across the regions. This effort was led by Region II and began in 2009. Periodic discussion of reliability topics: This effort included quarterly videoconferences among regional officials to share insights on the application of ROP inspection guidance and gain insight into different regional decision making. This effort was led by Region I and began in 2009. ROP self-assessments of inspection report quality: This effort included a team of staff from all regions that selected a cross-section of inspection reports from each region to assess their conformance with applicable guidance, identify key differences between regions, and identify any weaknesses. This effort was led by Region III and concluded in 2012. The ROP Reliability Initiative has not resulted in a formal report, and according to NRC officials, the sample of activities reviewed was not large enough to draw agencywide conclusions. In late 2011, NRC’s regional offices decided to continue the ROP Reliability Initiative by applying the approach of the individual efforts to an in-depth review of a specific inspection area each fiscal year. For example, the first such review done in fiscal year 2012 resulted in an internal memorandum making 25 recommendations to provide additional guidance and training on limited aspects of NRC’s efforts to inspect for weaknesses in licensees’ corrective action programs. NRC officials told us that the overall initiative is still under way and that ongoing activities are intended to improve regions’ consistency of actions adhering to the ROP guidance; however, agency officials said that, due to the ROP Enhancement Project (see below) and increased inspection activities following the Fukushima accident, the regional offices have not identified a specific inspection area to focus on for the fiscal year 2013 review. NRC has also conducted other efforts aimed at improving the consistency of its oversight processes: Assessment of regional enforcement. According to NRC officials, in 2011, NRC established an initiative aimed at improving consistency in how regional offices resolve inspection findings through enforcement activities. This initiative was conducted to address findings of enforcement inconsistency in the 2008 report by the NRC IG. Officials stated that NRC recently completed four regional assessments that were intended to improve consistency of interpreting minor and more-than-minor thresholds for violations. According to NRC officials, this initiative resulted in a final report in May 2013 recommending that regional enforcement staff conduct periodic audits of nonescalated enforcement actions. “Minor” ROP realignment. According to NRC officials, in 2006, NRC undertook an internal review of substantive cross-cutting issues across regions. The review resulted, in part, from complaints from industry that some plants were assigned cross-cutting aspects more frequently than others, especially in Region IV. NRC officials stated that Region IV led the review, which found that, while each region was following guidance, it also had its own culture and exercised some subjective judgment. Therefore, the regions had some differences in interpretations, especially in their approaches to determining what constitutes a more-than-minor performance deficiency. In response, according to NRC officials, NRC conducted additional training but made no key changes to its ROP procedures. In addition, NRC officials said that several of the agency’s formal ongoing reviews examine, to a limited extent, the consistency of its oversight processes: ROP Enhancement Project. In January 2013, as part of its annual self-assessment, NRC initiated the ROP Enhancement Project, which is intended as a long-term, strategic review of how it implements the ROP, among other things. NRC officials said that they expect this review to consider regional differences in the number of nonescalated findings, but according to an NRC status report, the assessment portion of the review has been delayed pending the outcome of an independent review of the ROP. NRC officials told us they expect procedural changes in response to the project to begin in 2014. ROP realignment process. In 2009, NRC implemented the ROP realignment process, a biennial review of its ROP baseline inspection procedures and inspection hours per procedure to ensure the most effective overall applications of inspection resources. NRC officials told us that this effort also touches on the consistency of how NRC implements its oversight of safety. Self-assessments. In 2001, NRC initiated annual self-assessments, which are to assess whether the ROP met its program goals and achieved its intended outcomes. NRC officials said that these self- assessments consider, to a limited extent, issues related to consistency, and according to NRC guidance, these self-assessments assess, in part, the extent to which NRC implements the ROP predictably. However, the biennial ROP realignment process evaluates specific inspection procedures agencywide to ensure the most effective application of inspection resources, and according to NRC guidance, the self-assessments are not intended to audit the performance of the regions in implementing the ROP. Thus even with taking these steps to examine the consistency of its oversight processes, agency officials told us that NRC has not conducted a comprehensive analysis of the causes of the differences in the number of nonescalated findings identified across regions. Under federal standards for internal control, managers at the functional or activity level are to compare actual performance to planned or expected results throughout the organization and analyze significant differences. Without conducting such an analysis, NRC (1) does not know whether its regional offices or individual inspectors are applying regulations and guidance consistently in handling findings; or (2) cannot identify other factors that may have led to the differences. Moreover, NRC’s 2008 to 2013 strategic plan states that the agency will establish and maintain stable and predictable regulatory programs and policies, and other NRC guidance states that the agency should use an objective, understandable, and predictable process to ensure that licensees fulfill their responsibility for ensuring the safe operation of commercial nuclear reactors. In particular, the agency’s enforcement manual emphasizes that staff should ensure that oversight efforts are objective and consistent. NRC is aware of differences across regions in identifying and resolving the findings that result from its oversight processes. However, without a comprehensive analysis of the causes of the differences in the number of nonescalated findings across regions, NRC cannot ensure that oversight efforts are objective and consistent, as specified in its enforcement manual, or know whether its regional offices or individual inspectors are applying regulations and guidance consistently. NRC maintains records of its identification of and response to both escalated and nonescalated findings; however, these records are difficult to search for several reasons, and limited our ability to assess the extent to which NRC followed its procedures and, thus, consistently identified and resolved findings. According to NRC’s strategic plan, the agency’s organizational values include openness in communication and decision making. Furthermore, NRC guidance states that the agency communicates ROP results to, in part, keep external stakeholders informed of licensee performance and to enhance confidence that NRC is accomplishing its mission. NRC’s enforcement policy states that its mission includes promoting the transparency and openness of its enforcement program for all stakeholders. In reviewing NRC’s findings data since the ROP’s inception in 2000 through 2012, we found that NRC has recorded approximately 12,000 findings––about 2 percent of which were escalated. For 95 percent of the findings data we reviewed—including numerous escalated findings—NRC did not include a case number for each finding, making it time-consuming and difficult to locate all documents associated with a single finding. According to NRC officials, although nonescalated findings each have a unique identifier, only the case number is searchable in NRC’s databases. NRC officials told us that, as a matter of policy, they do not assign case numbers to nonescalated findings; only to escalated findings. However, our review of NRC findings data also found 38 instances of escalated findings that had not been assigned a case number, during this period. The information NRC makes publicly available on its identification of and response to findings was also difficult to use. NRC communicates the results of much of its oversight process to the public through its ROP website. This website makes available inspection reports, assessment letters, and other general materials related to NRC’s oversight process. NRC also provides a quarterly summary of every reactor’s performance, consisting of its inspection findings, the color of each performance indicator, and the reactors’ placement on the action matrix. However, to review this information, users must search a link for each plant on a quarterly basis. Since the ROP has been in place for more than 12 years, users may have to search dozens of links per plant and read many different documents to get complete information on individual findings. In addition, while descriptions in each document contain information about whether a finding was associated with a cross-cutting issue, the website itself does not provide information on those plants that had open substantive cross-cutting issues prior to the most recent assessment period. This information can be found on the website by linking to each plant’s individual assessment letters. NRC program officials acknowledged that it is difficult for users of the website to determine which plants had substantive cross-cutting issues open in the past. Therefore, it is difficult to identify, over time, those that NRC views as having potentially more significant problems. NRC also makes publicly available its official recordkeeping system, the Agencywide Documents Access and Management System (ADAMS). ADAMS contains more than 730,000 documents dating back to November 1999, and several hundred new documents on NRC’s reactor oversight processes—as well as other NRC activities—are added each day. However, we found ADAMS difficult to navigate. For example, using an inspection report as our starting point, we tried to retrace the steps in NRC’s response to the findings in the report using ADAMS; however, our searches resulted in numerous unrelated documents as well as documents with ambiguous names that had to be opened to determine whether they were related to the findings. Further, we had no way of determining whether our searches returned a complete set of results and had identified all the documents related to the findings. NRC officials acknowledged that, while ADAMS can be used to conduct searches on specific words or other criteria, such searches may produce a large number of unrelated documents, in addition to relevant documents. We asked NRC officials how we could track a finding through its resolution, and they told us that doing so is difficult because findings and enforcement actions are recorded in separate databases and that these databases are not linked. The officials told us that users with expertise in both databases’ search capabilities could craft a data search that linked inspection and enforcement records. However, because external users cannot craft such a search, they cannot independently track NRC’s identification and resolution of findings. NRC’s Chairman reiterated the agency’s support for transparency in prepared remarks before the annual NRC Regulatory Information Conference in March 2013, stating that the agency must have a continued commitment to openness and transparency and communicate with interested parties in ways they understand, and that clear, consistent communication is a principle of good regulation. However, because external users cannot independently track findings and their resolution, NRC cannot ensure that the public, Congress, and others are kept informed of licensee performance, as specified in guidance, to enhance confidence that NRC is accomplishing its mission and following its oversight processes. NRC has both formal and informal methods for developing lessons learned to improve its oversight. Formal methods include agencywide programs and annual assessments. Informal methods include reaching out to peer groups and technical experts throughout the agency and accessing various agency databases. Although NRC guidance directs inspectors to use information in agency databases on past experiences to plan and conduct future inspection activities, inspectors face challenges accessing this information, which may limit their ability to use it. NRC has ongoing, formal methods through which it collects and analyzes information to develop lessons learned for improving reactor oversight, including the following agencywide programs: Operating Experience Program, which captures information on past experience based on inspection findings, events, and documents from industry, international nuclear agencies, and others to inform agency activities, including reactor inspections. Generic Issues Program, which tracks the status and resolutions of certain issues involving public health and safety, among other things, that could affect multiple entities under NRC jurisdiction, such as multiple commercial nuclear plants. ROP Feedback Program, which enables staff to submit comments and suggestions for improving the ROP based on their experiences; a central coordinator then directs these comments and suggestions to appropriate internal stakeholders for their review. Industry Trends Program, which monitors trends in indicators of industry performance. NRC evaluates any adverse trends to determine whether regulatory action is appropriate, and reports statistically significant trends to Congress. Monthly ROP working group meetings, which, according to NRC officials, NRC hosts and include the Nuclear Energy Institute, other industry representatives, and members of the public to discuss operating experience, inspection and performance assessment topics, potential changes and questions regarding performance indicator guidance, and other topics. Additionally, according to NRC documents, NRC identifies lessons learned during its annual self-assessments to determine whether the ROP met goals and during its biennial ROP realignment process. For example, the ROP realignment process assesses feedback from inspectors and other NRC officials submitted through the ROP Feedback Program. NRC has also undertaken special initiatives, such as the Fukushima Near-Term Task Force, to develop lessons learned from the accident at the Fukushima Daiichi Nuclear Power Plant in Japan that it could apply in its oversight of U.S. commercial nuclear power reactors. NRC convened the task force in 2011 to review its processes and regulations and determine whether lessons learned from the accident could inform its oversight processes. The task force concluded that a sequence of events like the Fukushima accident is unlikely to occur in the United States and that the continued operation of the nation’s commercial nuclear reactors does not pose an imminent risk to public health and safety. In addition, in 2011 the task force made 12 recommendations, such as for NRC to clarify its regulatory framework and to require licensees to reevaluate and upgrade seismic and flooding protection of reactors and related equipment, strengthen capabilities at all reactors to withstand loss of electrical power, and take other actions to better protect their plants for a low-probability high-impact event. NRC accepted these recommendations and is in the process of implementing them (see app. X). To follow up on the task force’s recommendations, in 2011, NRC established the Japan Lessons Learned Project Directorate—a group of over 20 NRC staff focused on implementing the lessons the task force identified. As part of this effort, NRC issued the following three orders to licensees in March 2012: improve capability to reliably and remotely monitor a wider range of conditions in the pools that contain spent fuel; install vent systems for certain types of reactors to help prevent an excess buildup of hydrogen gas in the reactor buildings; enhance plants’ capabilities to maintain or restore core cooling, containment, and spent fuel pool cooling in the case of external events, such as an earthquake, that exceeds plants’ design capabilities. NRC has also undertaken special initiatives in response to other unique events. For example, following the terrorist attacks on September 11, 2001, NRC issued orders to licensees to enhance security measures to protect their reactors against an increased terrorism threat. In addition, in 2002, after extensive degradation was discovered in the reactor vessel head at the Davis-Besse Nuclear Power Station in Ohio, NRC established a lessons learned task force and implemented many of its recommendations, including inspection procedure changes, enhancing its training program, and enhancing aspects of program management of the ROP. In May 2004, we made several recommendations to ensure that NRC addresses weaknesses that contributed to the Davis-Besse incident, which NRC has since implemented. NRC officials told us they also have more informal methods of collecting and analyzing information to develop lessons learned for improving reactor oversight. These informal means include reaching out to peers by telephone or e-mail, reaching out to regional or headquarters technical experts by telephone or e-mail, and informal gatherings during peer group meetings. For example, several resident inspectors told us they typically rely on a small group of fellow resident inspectors—often within the same branch overseeing a small number of plants—that they call periodically for updates on issues about which they are known to have prior experience. Inspectors told us that this type of outreach is especially important because it allows them to tap into other inspectors’ different experiences performing inspections and unique engineering expertise, given that resident inspectors come from a variety of engineering backgrounds. They also told us that this form of outreach can have a large influence on an inspector’s perspective about potential findings. Resident inspectors stated that they hold many informal discussions about lessons learned— including sharing findings and reviewing changes to guidance—during their semiannual conferences with peers from across their region and during periodic visits to plants in other regions. NRC uses e-mail to distribute updates agencywide to its guidance and other policy statements on how to respond to lessons learned from different plants; however, according to inspectors, individual inspectors are responsible for incorporating these lessons learned into their oversight activities. In addition, according to NRC officials, each region determines its policy for e-mailing lessons learned from across the region or lessons learned with generic safety implications. Although NRC guidance directs inspectors to use information on past experiences to plan and conduct future inspection activities, inspectors reported facing challenges in accessing information on past experiences, which may limit their ability to benefit from it. Under NRC guidance, inspectors are to use information on past plant experiences to prepare for, conduct, and document inspection activities. According to several inspectors, this information can be important for helping them choose inspection samples. Some inspectors we interviewed also stated that complete access to lessons learned from past plant experience is important to help them understand how NRC identified and resolved similar findings at other plants. In addition, industry representatives have stated that information on past experiences is beneficial because the industry is mature and there is a robust body of information on past experiences to learn from. However, several NRC officials told us that the Reactor Operating Experience (ROE) Gateway—the agency’s internal website for the Operating Experience Program—and its search tools are not user- friendly. For example, they noted that the website provides links to more than a dozen search tools that all contain different information but does not explain how to use them. The officials said that providing instructions on how to use these tools would be helpful. Moreover, they told us that conducting a thorough search on a specific topic may require multiple keyword searches because different reactor equipment manufacturers use different terms to describe the same type of equipment. For example, one manufacturer of commercial nuclear reactors calls certain pumps Auxiliary Feedwater Pumps, while another manufacturer calls them Emergency Feedwater Pumps, although both serve the same function— removing heat from the reactor core when the plant experiences a complete loss of electrical power. As a result, inspectors and other agency users—including officials in the Operating Experience Program and technical specialists in the regional offices—have to conduct searches on several possible keywords in each of the various search tools. NRC officials told us the various terms used to describe the same equipment are not officially documented so staff must learn about them through their own experiences. For example, if an NRC official encountered a problem at a plant with a particular type of pump, using ROE Gateway to search for past experiences with this pump would require the official to know that this piece of equipment had more than one name and to search on both names in each of the search tools. At least one of the search tools on ROE Gateway now uses drop-down lists to eliminate the need to conduct multiple keyword searches, but the remaining search tools do not have this capability. Given the challenges in navigating ROE Gateway, several resident inspectors told us they prefer contacting other inspectors informally or requesting assistance from NRC headquarters staff when trying to obtain information on past experience. They also told us they have developed informal “workarounds” to facilitate searches, such as creating and sharing slide presentations with one another on keyword searches for various common inquiries. We have previously reported that informal relationships could end once personnel move to their next assignments. Thus an informal workaround cannot substitute for a user-friendly, searchable system. Without better search tools, inspectors could overly rely on information available through informal channels rather than the more comprehensive information located in agency databases. NRC guidance states that the efficient retrieval of information on past experiences is a basic requirement for meeting agencywide objectives and that such information is necessary to improve safety assessments and NRC decisions. Further, NRC officials noted that inspectors have varied backgrounds—that is, some may have expertise in mechanical engineering, while others have expertise in electrical engineering— therefore they depend on NRC’s network of information to assess most issues and determine their importance. Past inspection results and related information are crucial parts of that network. NRC officials have acknowledged the difficulty of using ROE Gateway and noted at their most recent annual meeting in March 2013 that NRC has struggled to make information about past experiences accessible and distribute this information efficiently. Several resident inspectors also told us that e-mail updates on past experiences could be managed more effectively. For example, once resident inspectors receive an e-mail, it is their responsibility to incorporate the information on past experiences at their plant. However, these resident inspectors noted that not all e-mail updates apply to all plants; for example, an update may apply to a certain type of reactor that is not in use at all plants. Some resident inspectors stated that one way to improve this system would be to prioritize the e-mail notices and indicate the extent to which they are relevant to the inspectors. In addition, some resident inspectors noted that nonurgent e-mail updates should be compiled, whereas now they are included alongside all e-mail updates. Resident inspectors play an essential role in ensuring that reactors are operating safely because they have the opportunity and authority to, at any time, physically inspect plant equipment and operations, review plant records, and verify the accuracy of licensee-reported quantitative measures or indicators of plant performance. NRC officials told us that, because of their essential role in NRC’s oversight, inspectors need complete and efficient access to all the information necessary to do their jobs effectively. In addition, information on past plant performance and oversight actions helps inspectors know where to begin looking for potential issues of concern, and NRC guidance states that inspectors should consider this information in preparing for, conducting, and documenting inspection activities. For example, prior to the reactor damage found at the Davis-Besse plant in 2002, inspectors did not regularly focus on identifying reactor vessel head corrosion; however, as a result of this incident, NRC inspectors now focus on this issue regularly. NRC oversees the safety of commercial nuclear power reactors using established, ongoing processes. NRC’s oversight has taken on even greater importance as many commercial reactors in the United States are operating under renewed licenses that will allow them to operate beyond their initial 40-year operating periods. NRC is aware of differences across its regions in the identification and resolution of findings that result from its oversight processes and has taken some steps to address them, particularly in the differences of nonescalated findings. However, while NRC has undertaken these steps, NRC has not conducted a comprehensive analysis of these differences consistent with federal standards of internal control. Without a comprehensive analysis of the differences in the number of nonescalated findings across regions and their causes, NRC cannot ensure that oversight efforts are objective and consistent, as specified in its enforcement manual, or know whether its regional offices or individual inspectors are not applying regulations and guidance consistently. Furthermore, NRC policy states that the agency’s mission includes promoting transparency and openness for all stakeholders. As part of such transparency, NRC makes publicly available its official recordkeeping system, which contains hundreds of thousands of documents on NRC’s reactor oversight processes—as well as other NRC activities. However, we found this system difficult to navigate, and external users cannot use it to independently track findings, all documents related to the findings, and the findings’ resolution. As a result, NRC cannot ensure that the public, Congress, and others are kept informed of licensee performance, as specified in agency guidance, to enhance public confidence that NRC is accomplishing its mission and following its oversight processes. Information about reactor operators’ past experiences and NRC’s responses to them also plays a key role in NRC’s oversight processes. Although NRC guidance directs inspectors to use information on past experiences to plan and conduct future inspection activities, inspectors reported facing challenges in accessing information on past experiences, which may limit their ability to benefit from this information. Given the challenges in navigating ROE Gateway, several resident inspectors reported contacting other inspectors informally or requesting assistance from NRC headquarters staff when trying to obtain information on past experience. Without better search tools, inspectors could overly rely on information available through informal channels. NRC guidance states that the efficient retrieval of information on past experiences is a basic requirement for meeting agencywide objectives and that such information is necessary to improve safety assessments and NRC decisions. To improve NRC’s oversight processes, we are making three recommendations to the NRC Commissioners: To better meet its goal of implementing objective and consistent oversight, direct agency managers to conduct a comprehensive analysis of the causes of the differences in the identification and resolution of findings. To improve transparency and better enable the public, Congress, and others to independently track findings, all documents related to the findings, and the findings’ resolution, direct the agency to either modify NRC’s publicly available recordkeeping system to do so or develop a publicly accessible tool that does so. To help NRC staff more efficiently use past experiences in their oversight activities, direct agency officials to evaluate the challenges inspectors face in retrieving all relevant information on plant performance and previous oversight activities and improve its systems accordingly to address these challenges. We provided a draft copy of this report to the Executive Director for Operations of NRC for review and comment. In its written comments, reproduced in appendix XI, NRC generally agreed with our findings and recommendations. NRC also provided technical comments, which we incorporated, as appropriate. To address our first recommendation, NRC stated that it will revisit its initiatives with respect to implementation of the ROP and the nonescalated enforcement process to identify potential enhancements. For our second recommendation, NRC stated that it will identify ways to improve transparency and track documents related to inspection findings through improved tools to facilitate public access to inspection information. To address our third recommendation, NRC stated that it will make plant performance and oversight information more readily searchable and available to inspection staff and other NRC personnel. In addition, in its comment letter, concerning regional differences, NRC stated that, although it believes adequate internal controls to ensure alignment between regions exist through program office oversight and audits, among other things, it agrees to seek enhancements in this area. NRC raised concerns about repeated references in the draft report to the use of professional judgment by NRC staff members in the ROP and Traditional Enforcement Process, stating that these references imply a high degree of subjectivity in the agency’s implementation of its oversight processes and that its use of professional judgment is excessive or inconsistent. NRC stated that it believes its use of professional judgment is limited and controlled through its guidance. As stated in the report, we agree that NRC’s oversight processes are largely prescribed in guidance. 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, NRC, and other interested parties. In addition, this report also will be available at no charge on the GAO website 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 XII. Our objectives were to (1) describe how the Nuclear Regulatory Commission (NRC) implements its processes for overseeing the safety of commercial nuclear power reactors; (2) evaluate the extent to which NRC consistently identifies and resolves findings through these processes; and (3) describe NRC’s methods for developing lessons learned to improve its oversight and challenges, if any, NRC faces in doing so. To describe how NRC implements its processes for overseeing the safety of commercial nuclear power reactors, we reviewed relevant federal laws, regulations, and guidance, including NRC’s Enforcement Policy, Enforcement Manual, and Inspection Manual, among many other guidance documents. We also reviewed previous GAO and NRC Inspector General reports that identified safety-related challenges or made recommendations for improving NRC’s oversight of reactor safety, and we reviewed documentation of NRC efforts to update its oversight processes. We interviewed NRC headquarters officials from the Offices of Nuclear Reactor Regulation, Enforcement, Nuclear Regulatory Research, and the Inspector General. We also conducted semistructured interviews with officials from all four NRC regions, as well as resident inspectors and plant representatives during site visits to five nuclear power plants (discussed further below). During these semistructured interviews, we asked NRC officials and plant representatives about (1) the implementation and consistency of NRC’s oversight activities, (2) the extent to which NRC’s oversight includes lessons learned from operating experience and safety-related findings, (3) the level of communication between NRC and plant representatives, (4) NRC actions taken to identify and resolve specific safety-related findings, and (5) site-specific considerations related to safety. In addition, we interviewed representatives from the Nuclear Energy Institute, the Union of Concerned Scientists, academic specialists, and other groups and individuals to discuss their views and gain additional insight into NRC’s oversight of reactor safety. We made site visits to a nonprobability sample of five nuclear power plants. During these site visits, we held separate semistructured interviews with NRC resident inspectors and plant representatives, including licensee managers and plant operators, to obtain in-depth information about their experiences with NRC’s oversight process. We also toured several of the sites with the resident inspectors and observed areas and equipment related to previous findings, in addition to current issues of concern being assessed for potential findings. Because this was a nonprobability sample, the information we gathered from these site visits is not generalizable to all U.S. nuclear power plants but provides important illustrative information for understanding the oversight of reactors at the selected plants. To select these sites, we applied the following criteria to capture a variety of characteristics: whether NRC’s assessment of the plant’s safety significance has changed in the past 2 years, and whether, collectively, they were located in multiple NRC regions, operated by different licensees, and included different reactor types. In Region I, we visited the Calvert Cliffs Nuclear Power Plant in Maryland. In Region III, we visited the Byron Station in Illinois and Palisades Nuclear Plant in Michigan. In Region IV, we visited the Cooper Nuclear Station in Nebraska and Wolf Creek Generating Station in Kansas. To evaluate the extent to which NRC consistently identifies and resolves findings through its processes for overseeing reactor safety, in addition to reviewing NRC guidance and interviewing NRC officials (as described above), we analyzed the nonsecurity findings and violations for all plants from the beginning of NRC’s Reactor Oversight Process in 2000 through 2012. We obtained these data from NRC’s Reactor Program System database. We also analyzed separate NRC data on (1) the number of inspection hours from 2000 through 2012, (2) descriptive information about licensees, (3) substantive cross-cutting issues assigned to each plant from 2001 through 2012, and (4) the quarterly action matrix assessment for each reactor from 2001 through 2012. In order to assess the reliability of the data we analyzed, we reviewed database documentation, interviewed NRC officials familiar with the data, and conducted electronic tests of the data, looking for missing values, outliers, or other anomalies. We determined that the data were sufficiently reliable for our purposes. We also searched documents in NRC’s publicly available, web-based Agencywide Documents Access and Management System (ADAMS) database, which is the official recordkeeping system for all NRC documents. To describe NRC’s methods for developing lessons learned to improve its oversight and challenges, if any, NRC faces in doing so, in addition to reviewing NRC guidance and interviewing NRC officials (as described above), we observed NRC headquarters officials demonstrating the various computer-based tools they use for communicating and providing access to information on past experiences and lessons learned. We also observed resident inspectors, during our site visits to nuclear power plants, demonstrating how they access agency information on past experiences and lessons learned. In addition, we observed meetings where NRC staff updated the Commission and the public on the status of the development and implementation of lessons learned from the Fukushima disaster, among other safety-related concerns. We conducted this performance audit from May 2012 to September 2013 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. This appendix provides summary information about the 104 commercial nuclear power reactors at 65 power plants for which we analyzed NRC data and that were operating in the United States through the end of calendar year 2012. For each reactor, table 14 lists the NRC region, state, date commercial operation began, and licensee. Appendix III: NRC Safety Cornerstones and Related Performance Indicators Initiating Events cornerstone – This cornerstone focuses on operations and events at a nuclear plant that could lead to a possible accident, if plant safety systems did not intervene. These events could include equipment failures leading to a plant shutdown, shutdowns with unexpected complications, or large changes in the plant’s power output. (In this table, “scram” refers to automatic and manual reactor shutdowns.) Performance indicator Unplanned scrams per 7,000 critical hours This performance indicator monitors the number of unplanned scrams. It measures the rate of scrams per year of operation at power and provides an indication of initiating event frequency. The value of 7,000 hours is used because it represents 1 year of reactor operation at 80 percent capacity. This performance indicator monitors the subset of unplanned scrams while critical that require additional operator actions beyond that of the “normal” scram. Such events or conditions have the potential to present additional challenges to the plant operations staff and therefore, may be more risk-significant than uncomplicated scrams. This performance indicator monitors the number of unplanned power changes (excluding scrams) that could have, under other plant conditions, challenged safety functions. It may provide leading indication of risk-significant events but is not itself risk-significant. The indicator measures the number of plant power changes for a typical year of operation at power. Mitigating Systems cornerstone – This cornerstone measures the function of safety systems designed to prevent an accident or reduce the consequences of a possible accident. The equipment is checked by periodic testing and through actual performance. Performance indicator Mitigating system performance index – emergency alternating current power systems Objective This performance indicator monitors the readiness of the emergency alternating current power systems to perform their safety functions in response to off-normal events or accidents. This performance indicator monitors the readiness of the high pressure injection systems to perform their safety functions in response to off-normal events or accidents. This performance indicator monitors the readiness of the heat removal systems to perform their safety functions in response to off-normal events or accidents. This performance indicator monitors the readiness of the residual heat removal systems to perform their safety functions in response to off-normal events or accidents. This performance indicator monitors the readiness of the cooling water support systems to perform their safety functions in response to off-normal events or accidents. This performance indicator monitors events or conditions that alone prevented, or could have prevented, the fulfillment of the safety function of structures or systems that are needed to: shut down the reactor and maintain it in a safe shutdown condition; remove residual heat; control the release of radioactive material; or mitigate the consequences of an accident. Barrier Integrity cornerstone – This cornerstone focuses on the physical barriers between the highly radioactive materials in fuel within the reactor and the public and the environment outside the plant. These barriers are the sealed rods containing the fuel pellets, the heavy steel reactor vessel and associated piping, and the reinforced concrete containment building surrounding the reactor. The integrity of the fuel rods, the vessel, and the piping is continuously checked for leakage, while the ability of the containment to prevent leakage is measured on a regular basis. Performance indicator Reactor coolant system specific activity Objective This performance indicator monitors the integrity of the fuel cladding, the first of the three barriers to prevent the release of fission products. It measures the radioactivity in the reactor coolant system as an indication of functionality of the cladding. This performance indicator monitors the integrity of the reactor coolant system pressure boundary, the second of the three barriers to prevent the release of fission products. It measures reactor coolant system identified leakage as a percentage of the technical specification allowable identified leakage to provide an indication of reactor coolant system integrity. Emergency Preparedness cornerstone –This cornerstone measures the effectiveness of plant staff in carrying out emergency plans for responding to a possible accident. Such emergency plans are tested every 2 years during emergency exercises involving the plant staff and local, state, and, in some cases, federal agencies. Performance indicator Drill/exercise performance Objective This performance indicator monitors timely and accurate licensee performance in drills and exercises when presented with opportunities for classification of emergencies, notification of off-site authorities, and development of protective action recommendations. It is the ratio, in percent, of timely and accurate performance of those actions to total opportunities. This performance indicator tracks the participation of emergency response organization members assigned to fill key positions in performance enhancing experiences, and through linkage to the drill/exercise performance indicator ensures that the risk- significant aspects of classification, notification, and protective action recommendations development are evaluated and included in the performance indicator process. This indicator measures the percentage of emergency response organization members assigned to fill key positions who have participated recently in performance-enhancing experiences such as drills, exercises, or in an actual event. This performance indicator monitors the reliability of the off-site alert and notification system, a critical link for alerting and notifying the public of the need to take protective actions. It provides the percentage of the sirens that are capable of performing their safety function based on regularly scheduled tests. Occupational Radiation Safety cornerstone – NRC regulations set a limit on radiation doses received by plant workers, and this cornerstone monitors the effectiveness of the plant’s program to control and minimize those doses. Performance indicator Occupational exposure control effectiveness Objective This performance indicator monitors the control of access to and work activities within radiologically-significant areas of the plant and occurrences involving degradation or failure of radiation safety barriers that result in readily-identifiable unintended dose. Public Radiation Safety cornerstone – This cornerstone measures the procedures and systems designed to minimize radioactive releases from a nuclear plant during normal operations and to keep those releases within federal limits. Objective This performance indicator assesses the performance of the program to control radiological effluent occurrences, which are radiological releases that exceed pre-set limits for liquid and gaseous releases. This appendix provides summary information about NRC’s inspection procedures. Table 15 lists the safety cornerstone, title, and objective for each of the 36 safety-related (nonsecurity) baseline inspection procedures. Table 16 lists the title and objective for each of the 3 supplemental inspection procedures, and table 17 lists the title and objective for each of the 3 reactive inspection procedures. This appendix provides summary information about select examples of NRC findings and violations. Table 18 provides a brief description, nuclear power plant location, and date recorded for select examples of NRC findings illustrating different risk significance levels. Table 19 provides a brief description, nuclear power plant location, and date recorded for select examples of NRC violations illustrating different severity levels. This appendix provides performance information about the 104 commercial nuclear power reactors at 65 power plants for which we analyzed NRC data and that were operating in the United States through the end of calendar year 2012. Table 20 lists the number of nonescalated findings identified at each plant from 2000 through 2012. This appendix provides performance information about the 104 commercial nuclear power reactors at 65 power plants for which we analyzed NRC data and that were operating in the United States through the end of calendar year 2012. Based on NRC’s assessment of licensee performance under the ROP, NRC places each of the licensee’s reactors into one of five performance categories on its action matrix, which corresponds to increased levels of oversight. The action matrix is NRC’s formal method of determining how much additional oversight—mostly in the form of supplemental inspections—is required on the basis of the number and risk significance of performance indicators and inspection findings. The level of oversight reported here corresponds to the highest level the plant received during the year, even if it was only a portion of the year. Thus, if a plant was placed into a different category each quarter, the highest category in which it was placed is reported here. (See table 21.) This appendix provides performance information about the 104 commercial nuclear power reactors at 65 power plants for which we analyzed NRC data and that were operating in the United States through the end of calendar year 2012. Table 22 lists the substantive cross-cutting issues assigned to each reactor from 2001 through 2012. This appendix provides performance information about the 104 commercial nuclear power reactors at 65 power plants for which we analyzed NRC data and that were operating in the United States through the end of calendar year 2012. Table 23 lists the number of escalated findings identified at each plant from 2000 through 2012. NRC convened the Fukushima Near-Term Task Force to review its processes and regulations and determine whether its oversight could be informed by lessons learned from the March 2011 disaster at the Fukushima Daiichi Nuclear Power Plant in Japan. The task force concluded that a sequence of events like the Fukushima accident is unlikely to occur in the United States and that the continued operation of the nation’s commercial nuclear reactors does not pose an imminent risk to public health and safety. To improve NRC’s oversight, the task force recommended: 1. Establishing a logical, systematic, and coherent regulatory framework for adequate protection that appropriately balances defense-in-depth and risk considerations. 2. NRC require licensees to reevaluate and upgrade as necessary the design-basis seismic and flooding protection of structures, systems, and components for each operating reactor. 3. As part of the longer term review, that NRC evaluate potential enhancements to the capability to prevent or mitigate seismically induced fires and floods. 4. NRC strengthen station blackout mitigation capability at all operating and new reactors for design-basis and beyond-design-basis external events. 5. Requiring reliable hardened vent designs in boiling water reactor facilities with Mark I and Mark II containments. 6. As part of the longer term review, that NRC identify insights about hydrogen control and mitigation inside containment or in other buildings as additional information is revealed through further study of the Fukushima Dai-ichi accident. 7. Enhancing spent fuel pool makeup capability and instrumentation for the spent fuel pool. 8. Strengthening and integrating onsite emergency response capabilities such as emergency operating procedures, severe accident management guidelines, and extensive damage mitigation guidelines. 9. NRC require that facility emergency plans address prolonged station blackout and multiunit events. 10. As part of the longer term review, that NRC pursue additional emergency preparedness topics related to multiunit events and prolonged station blackout. 11. As part of the longer term review, that NRC should pursue emergency preparedness topics related to decisionmaking, radiation monitoring, and public education. 12. NRC strengthen regulatory oversight of licensee safety performance (i.e., the Reactor Oversight Process) by focusing more attention on defense-in-depth requirements consistent with the recommended defense-in-depth framework. In addition to the contact named above, Ned Woodward (Assistant Director), John Barrett, Elizabeth Beardsley, John Delicath, R. Scott Fletcher, Kimberly Gianopoulos, Cindy Gilbert, Chad M. Gorman, Catherine Hurley, Jonathan Kucskar, Alison O’Neill, Dan Royer, Carol Herrnstadt Shulman, and Michelle R. Wong made key contributions to this report.

Summary: The 2011 disaster at Japan's Fukushima Daiichi Nuclear Power Plant demonstrated that unexpected nuclear accidents with extreme consequences can occur and, thus, heightened concerns about NRC's ability to oversee the safety of U.S. commercial nuclear power reactors. NRC oversees safety through multiple processes, such as physically inspecting reactors and also responding to signs of declining performance (i.e., findings) or violations of its requirements. GAO was asked to review NRC's oversight of the U.S. nuclear power industry. This report examines (1) how NRC implements its processes for overseeing the safety of commercial nuclear power reactors; (2) the extent to which NRC consistently identifies and resolves findings through these processes; and (3) NRC's methods for developing lessons learned to improve its oversight and challenges, if any, NRC faces in doing so. GAO reviewed NRC policies and guidance; visited five nuclear power plants located in multiple NRC regions; analyzed NRC data on findings, violations, licensee performance, and inspection hours; interviewed NRC officials and industry representatives; and observed demonstrations of NRC's database search tools. The Nuclear Regulatory Commission (NRC) relies on its staff's professional judgment in implementing its processes for overseeing the safety of U.S. commercial nuclear power reactors. In implementing this oversight, NRC allocates specific roles and responsibilities to resident inspectors assigned to each plant, regional officials at one of four regional offices responsible for most oversight activities, headquarters officials, and the nuclear power industry. NRC also builds into its processes incentives for plant managers to identify concerns about reactor safety, report those concerns to NRC, and take prompt actions to correct them. NRC's processes for identifying and assessing findings and violations are based on prescribed agency procedures and include several points where NRC staff must exercise their professional judgment, such as determining whether issues of concern identified during physical inspections constitute findings or violations and the risk significance of any findings or the severity of any violations, among other things. NRC is aware of differences across regional offices in identifying and resolving findings that result from physical inspections. GAO's analysis of NRC's data indicated that the number of escalated findings had fewer differences across regions than nonescalated findings, which are lower-risk findings and less severe violations. According to NRC officials, several factors, such as the hours spent on inspections, may explain the differences in nonescalated findings. However, GAO found that the regional office with the fewest reactors and the fewest inspection hours had the most nonescalated findings. NRC officials and industry representatives have raised concerns that the differences may also be due to differences in how NRC staff identify and resolve findings. NRC has taken some steps to examine the consistency of its oversight. For example, in 2009, the four regional offices implemented an initiative to explore how the regional offices identify and assess inspection findings. However, NRC has not conducted a comprehensive analysis of the causes of the differences in the number of nonescalated findings across regions. Under federal standards for internal control, managers are to compare actual performance with planned or expected results throughout the organization and analyze significant differences. Without such an analysis, NRC does not know whether its regional offices are applying regulations and guidance consistently. NRC has both formal and informal methods for developing lessons learned to improve its oversight. Formal methods include agencywide programs, annual and biennial assessments, and special initiatives. Informal methods include reaching out to peers and technical experts across the agency and accessing various agency databases. Although NRC guidance directs inspectors to use information in agency databases on past experiences to plan and conduct inspection activities, inspectors face challenges accessing this information, which may limit their ability to use it. For example, several NRC inspectors reported contacting other inspectors informally because NRC's database search tools contain limited instructions and do not ensure thorough results. Without better search tools, inspectors may overly rely on information available through informal channels. GAO recommends, among other things, that NRC analyze the causes of differences in identifying and resolving findings across regional offices and address these differences, and that it improve its database search tools. NRC agreed with GAO's recommendations.