ML20126A738
| ML20126A738 | |
| Person / Time | |
|---|---|
| Issue date: | 12/09/1992 |
| From: | Taylor J NRC OFFICE OF THE EXECUTIVE DIRECTOR FOR OPERATIONS (EDO) |
| To: | |
| References | |
| SECY-92-407, NUDOCS 9212210205 | |
| Download: ML20126A738 (48) | |
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December 9, 1992
- SEcY-92-407 (Information)
For: The Commissioners From: James M. Taylor Executive Director for Operations
Subject:
THE INDEPENDENT R0,'. OF TiiE OFFICE FOR ANALYSIS AND EVALVATION OF OPERATIONAL DATA IN THE ASSESSMENT OF OPERATIONAL EXPERIENCE AND THE INVESTIGATION OF OPERATIONAL EVENTS
Purpose:
To inform the Commission of the effectiveness of the Office for Analysis and Evaluation of Operational Data (AE00) in its independent role of assessment, investigation and feedback of '
operational experience and events at facilities licensed by the NRC.
Backaround: In January 1979 the General Accounting Office (GAO), in a report to the Chairman, summarized the results of its evaluation on the NRC's review and use of operational experience and data from licensed facilities. The GA0 reported that the NRC had no systematic, defined, or dedicated program to analyze and feed back to NRC offices and to licensees and industry the lessons of ~
experience. In March 1979 the Three Mile Island-2 (TMI-2) accident occurred and subsequent investigations found that two previous events at other nuclear plants were precursors to the THI-2 accident.
Contacts: NOTE: TO BE MADE PUBLICLY AVAILABLE R pessard, AE00 AT THE COMMISSION BRIEFING 42 SCHEDULED FOR DECEMBER 17, 1%2 Thomas M. Novak, AE00 492-4484
The Commissioners 2 On February 22, 1979, the Commission requested a briefing on the NRC's program and requirements for operational data collection, assessment, and feedback. The Commission was briefed on the subject on April 19, 1979, at which time the Executive Director for Operations (ED0) appointed a task force to provide an in-depth investigation of NRC's program and report to the Commission its recommendations for im)rovements. On June 4, 1979, the task force recommended to tie Commission, among other actions, that an agency-wide office be established to support the efforts of the program offices to analyze and feed back the lessons of operational experience. On July 12, 1979, the Commission approved the formation of the Office for Analysis and Evaluation of Operational Data (AE00) reporting to the EDO and directed that~ other offices also have the capability to analyze operating experience.
In conjunction with the FY 1985 Appropriations Act, Congress ,
required the NRC to conduct a study, to be submitted to Congress, on the need for and feasibility of an independent organization responsible for conducting investigations of safety significant events and incidents at facilities licensed by the NRC. AE00 contracted with Brookhaven National Laboratory (BNL) to conduct the study, which identified a number of ways that the NRC program for the investigation of significant operational incidents could be improved. On June 10, 1985, in response to ,
the BNL report, the staff recommended (SECY-85-208) a number of changes to the NRC's program for investigation of significant operational events through the establishment of an NRC Incident Investigation Program (IIP). In October 1985,.the Commission approved establishment of the IIP and assigned overall program.
development and administrative responsibilities to AE00.
Since its formation in 1979, AE00 has provided, as one of its primary missions, a strong, independent capability-for the analysis and evaluation of operational data. AE00 serves as the NRC focal point for independent assessment of operational events through the review, analysis, and_ evaluation of both reactor and nonreactor operational safety experience. This effort is conducted independent of licensing and other staff activities and independent of regulatory positions and prior commitments and agreements. The role of AEOD was strengthened and expanded in 1987 in accordance with the Commission's emphasis on operational safety performance. The Diagnostic Evaluation Program (DEP) and the Performance Indicator (PI) Program were moved from the then existing Office of Inspection and Enforcement to AE00 at this time, along with the Technical Training Center (TTC), the Incident Response Program, and the NRC's Operations Center.
s The Commissioners 3 Discussio_q: Operational Exoerience Assessment One of the primary functions of AE00 is the identification of safety issues that require new or additional NRC staff actions.
Operational data is analyzed to identify and provide:
quantitative bases for potential new safety issues; evaluate the effectiveness of current regulations, regulatory actions', and- ,
initiatives taken by licensees to resolve safety issues; and to help guide and focus AE00 studies, evaluations and reviews.
To accomplish its operational data assessment mission,.AE00 collects, reviews, analyzes, and disseminates operational data; publishes and evaluates plant performance indicators; identifies and analyzes significant operating events for insights-and-improved understanding; assesses significant trends.and patterns in the operational data; evaluates the applicability of events and their causes to other licensed facilities; and assesses the-adequacy of corrective actions taken to-address safety concerns identified from the operational data.
AE00 conducts studies and publishes reports of specific operational experience and precursor events and recommends- _
agency actions to reduce the likelihood and potential of- such events to lead to more serious events. All the reports issued by AEOD to date are listed in the current AE00 Annual Report.
AE00 findings and recommendations are addressed by the appropriate program office and this usually results in' generic -
correspondence,-resolution of generic issues and ' initiatives, taken by industry. Since 1979, AE00 has. issued 32 case studies with over 120 recommendations. Of these 120 recommendations, approximately 15 are being worked and remain open.
As a result of AE00 studies, the NRC has issued-approximately' 140 information notices and 10 bulletins. The AE00 reports were considered in forming the regulatory basis for-four. generic-letters,-and nine generic issues. They also contribute _d new-safety information to 11 ongoing' generic. issues and five unresolved safety' issues._ Utilities have taken actions to improve safety as a result of_both the above NRC generic correspondeice and AEOD studies that were not followed by generic corrispondence.
Human Factors Since 1983,-AEOD has conducted independentLstudies.of the
- effect of human performance on operating events. As part of-this independent mission to. study ~ operating. experience, AE0D-began a. program in 1990 to conduct studies of:the effect of human performance during selected power reactor events.. The.
studies.are intended to present information on factors that both helped or hindered operator performance. The focus'is
[
on control room operator performance.
.-.g
The Commissioners 4 Performance Indicators In addition to the quarterly-publication of- Pls, AE00 independently analyzes the PIs to identify licensees whose performance trends may warrant in depth analyses. These analyses include events reported to the_NRC pursuant to 10 CFR 50.73 to determine the underlying causes of licensee performance. The results of these analyses are compared - ,
with incident investigation team and augmented inspection team results, abnormal occurrence reports,. accident-sequence precursor events, and sal.P scores. -These comparisons are conducted to obtain an overall understanding of licensee strengths and weaknesses. AE00 uses these plant assessments-in preparation for the NRC semiannual -Senior Management Meetings (SMM).
Accident Se_quence Precursor Program AE0D analyzes selected operating events using the Accident Secuence Precursor (ASP) Program to gain insight into events-anc improve understanding of them from a risk perspective.
This quantitative analysis of operating experience-is diverse from other NRC efforts and provides an independent assessment of the importance of operating events. ASP-results are also used as a complementary measure of industry performance as well as a means of identifying technical issues warranting further work. AE0D's~ independent perspective and input into the process for. recommending plants to be-discussed at the SMMs are derived principally from AE00's plant assessments based on the PI Programi discussed earlir:r, and the ASP results.
Trends and Patterns AE00 routinely. analyzes the trends and patterns associated with reactor operational data. For example ~, in 1987 AE0DL performed a study of startup exper_ience for 22 new pla: ts-l- (less than two years old) to' determine performance -
differences with mature plants and the r_eason for the-differences. -In -1990- AE0D studied the progress in .the nuclear industry's reactor trip reduction program. More recently, AE00 has been developing and . implementing approaches to assess the effectiveness of genericcissues resolution through trends and patterns studies of emergency diesel. generator performance, service water:-system failures, and shutdown / low-power events. Trending the effectiveness of NRC and industry corrective actions is increasingly'_
important.
,~
The Commissioners 5 Reportino of Abnormal Occurrences t AE00 prepares the quarterly " Report'to Congress on Abnormal Occurrences" (NUREG-0090 series) and the associated Federal Rooister notices. After staff coordination of each quarterly abnormal occurrence (A0)_ report.- it-is sent to the EDO and then to the Commission for review and approval. An A0 may be an individual incident, a recurring event, a generic concern, or a series of incidents that the .
Commission determines is significant from the standpoint of_ -
public health or safety.
The quarterly A0 reports issued in 1991 included 14 events-from NRC licensees and 6 events from Agreement State licensees. None of these A0s occurred at.a nuclear power pl ant.
Annual Reports (NUREG 1272)
AEOD issues an annual report which includes the investigations conducted and principal findings and issues identified by AE0D_over the past year. Part'l of this report covers power reactors and presents-an overview of operating experience of the nuclear power _ industry, including comments about trends of some key performance measures. Part 2 covers nonreactors and presents a review of the events and concerns associated with-the use of licensed material in nonreactor applications.
Enclosure 1 provides a more detailed discussion of the'-
independent role and effectiveness of AE00 in the NRC's -
collection, assessment, and feedback of operational' data.
Incident Investications The IIP is agency-wide and investigates safety significant operational incidents at NRC-licensed facilities. -The most significant incidents are investigated by IITs reporting to-the EDO. Less significant-incidents are-investigated by-AITs reporting to the appropriate regional administrator. AE00 implements the IIP, with the assistance of other NRC. offices.
AITs are implemented by the regional' offices.-
AE00, after consultations with the appropriate regional .
administrator and office director (s), makes rec'ommendations to:
the EDO regarding the need for:an IIT, the proposed charter for the IIT and proposed members of the team.
The Director, AE00, independently reviews the draft IIT' report and forwards it to the EDO for approval. AE0D then drafts and forwards proposed generic and plant-specific IIT followup
I The Commissioners 6 actions to the EDO for approval and assignment, following consultation with the llT leader and responsible NRC offices and region. AE00 reports on the status of each action in the AE0D.
annual report.
Since 1985, seven llis have been conducted and they have been t highly effective in leading to a large number of significant -
technical lessons involving plant-specific and generic NRC actions. In addition, IITs have significantly contributed to the identification of potential weaknesses in NRC programs and regulatory oversight. In addition, a total of more than 90.AITs have been conducted by the regions. ,
AE0D has recently developed a new incident investigation option that has been proposed to the Commission. This option'provides for an investigation that would be authorized and chartered by the Commission for the investigation of incidents of extraordinary safety significance. Personnel conducting the investigation also would report directly to the Commission.
Enclosure 2 contains additional detailed information regarding the independent role and effectiveness of AE00 in the implementation of the llP.
Diaanostic Evaluations The DEP is agency-wide and prov_ ides an independent assessment of overall licensee safety performance and a determination of root cause(s) of any performance problems. The DEP augments information provided by other monitori.3 and inspection programs. The administration and management lof'the program.are independent of the licensing, inspection, and enforcemen.t processes.
AE00~ implements the DEP with the support of other NRC. offices.
and maintains the core capability for the conduct .of Diagnostic Evaluations (des). AE0D,.in coordination with the regions and headquarters offices, makes recommendations to the-ED0 regarding' a the need for a DE and, when the ED0 approves a DE, prepares a proposed DE plan.
The Director, AE0D approves the DE report,-forwards'it to the
.EDO for approval and-issuance, and, in consultation with the~DE-team (DET) and the. appropriate offices, drafts proposed.NRC generic and plant-specific followup' actions- for ' submittal' to? the EDO. -The status of each generic action, issued by the EDO, is reported in the AE00 Annual Report.
To date,10 des and-1 special evaluation have been conducted.
They have been highly effective in assessing licensee-performance and regulatory issues and providing feedback to: the
.The Commissioners 7 nuclear industry and the NRC for corrective actions. These actions have involved both plant-specific arid generic technical issues and safety programs.
Enclosure 3 contains additional information regarding the DEP,- V its accomplishments and independent activities.
Summarv: In summary, the AE0D programs, taken.as a whole, constitute the essential independent review and assessment of the safety performance at reactor and nonreactor facilities. AE00's independent reviews complement the operational data assessments conducted by the NRC regional offices and the Offices of Nuclear Reactor Regulation (NRR) and Nuclear Material Safety and Safeguards (NMSS). In this way AE0D provides both a quality assurance and an oversight function that reduces the likelihood that an important safety lesson will remain unlearned. AE00 has been highly effective in its independent role.
Coordination: The Office of the General Counsel has reviewed this paper and has no legal objection.
e f.<
..esM. Taylor f
iecutive Director for Operations
Enclosures:
- 1. Operational Experiencc Tssessment
- 2. Incident Investigation Program
- 3. Diagnostic Evaluation Program DISTRIB11 TION:
Cormnissioners OGC.
OCAA OIG OPP REGIONAL OFFICES EDO SECY-
fNCt0SURE 1 OPERATIONAL EXPERIENCE ASSESSMENT Backaround Since it was established in 1979, the Office for Analysis and Evaluation of
' Operational Data (AE00) has provided, as one of its primary missions, a strong, independent capability for the analysis and evaluation of operational data. AE0D provides a focal point within the NRC for independent assessments of operational events and experience through its collection, review, analysis, --
and evaluation of operational data for reactor and nonreactor facilities licensed by the NRC. AE0D's assessments are conducted independent of '
licensing and routine inspection activities and independent of regulatory positions, prior commitments, and technical agreements. AE00's independent-reviews complement the operational data assessments conducted by the NRC regional offices and the Offices of Nuclear Reactor Regulation (NRR) and .
Nuclear Material Safety and Safeguards (NMSS). In.this way-AEOD provides both a quality assurance and an oversight function through a process of checks and-balances that reduce the likelihood that an important safety lesson' will-remain unlearned. The findings, suggestions, and recommendations that flow from AEOD's reviews are usually addressed through the issuance of generic feedback correspondence, resolution of generic issues, and initiatives taken by industry. In 1985, the Accident Sequence Precursor (ASP) Program was transferred from the Office of Research to AE0D and the Commission. approved establishment of the Incident Investigation Program (IIP) and assigned overall program development and. administrative responsibilities to AE0D. In 1987, the role of AE00 was strengthened again when both the Diagnostic-Evaluation (DE) and the Performance Indicator (PI) Programs were moved from the former Office of Inspection and Enforcement to AE0D.
.To accomplish its operational data assessment mission, AE0D collects, reviews, analyzes, and disseminates operational data; publishes and evaluates plant performance indicators; identifies and analyzes significant operating events for insights and improved understanding; assesses significant trends and patterns in the operational data; evaluates the applicability of events and their causes to other licensed facilities; and: assesses the adequacy-of.
corrective actions taken to address safety concerns identified from the operational data. The AEOD Procedures Manual delineates how these functions are accomplished.
AE00 Studies One of the primary functions of' AE00 is the identification of safety issues-that require new or additional NRC staff actions. Operational data is analyzed to identify and provide a quantitative. basis for potential new safety-issues; to evaluate the effectiveness of current regulations, regulatory actions, and initiatives taken by licensees to resolve safety issues; and to
help guide and focus AE00 studies, evaluations, and reviews._ AE00 conducts-studies and publishes reports of specific operational experience and precursor events and recommends agency actions to reduce the likelihood and potential of such events to lead to more serious events.
In its analysis and evaluation of operational experience, AEOD reviews a broad range of operational data and reports submitted by licensees. Examples of these reports include those submitted in accordance with both 10 CFR 50.72, "Immediate Notification Requirements for Operating Nuclear Power Reactors,"
and 10 CFR 50.73, " Licensee Event Report System," the NRC's sequence coding-and search system (SCSS); and the data base of component failures in the nuclear plant reliability data system (NPRDS). NPRDS-is a system managed by; the Institute of Nuclear Power Operations (INPO). Other operational data reviewed by AE0D include: industry reports submitted in accordance with 10 CFR Part 21, " Reporting of Defects and Noncompliance"; NRC . regional and headquarters inspection reports; NRC preliminary notifications (PNs) of events or unusual occurrences; IIT and DET reports; and data on foreign reactor events. AE00 also conducts visits to licensee or vendor facilities to collect additional information and operational data. These data sources are used in various AE00 studies, such as case studies, special studies, engineering evaluations, and technical reviews and te conduct AE00 trends and patterns analyses and assess their safety implications.
AE00 independently selects the topics for its studies. Topics that have the- ,
potential to involve significant safety and risk issues.and generic implications are emphasized. Potential AE00 study topics are identified in -
several ways. Licensee events reported under 10 CFR 50.72 are discussed '
within AE00 and with other offices to identify potential areas of concern.
Routine screening of licensee event reports (LERs) and inspection reports and review of foreign reactor event reports submitted under the international ,
reporting system (IRS) may also give rise to potential study topics. A search of the operating experience data bases is frequently conducted to identify ,
other similar occurrences. Evidence of. potential generic applicability of an issue is usually found before committing significant resources required for more detailed study. Selection of a study topic is often influenced by:the-knowledge of the risks associated with system failures developed by existing probabiitstic risk assessments (PRAs) and ASP anolysis. Potential studies-for ,
important events are cresented to management for discussion.
AE0D " case studies" involve comprehensive and in depth analyses of significant safety issues. Case studies document .the technical basis _for AE00 recommendations for regulatory or industry actions. Before an AE00 case study report-is issued, it undergoes a rigorous peer review process to ensure _the technical accuracy and adequacy of its content. However, the recommendations contained in AE00 case' study reports are not subject to peer review and comment. To date, AE00 has issued 32 case study reports. Some of the reports issued for-these studies also have been published as Nt' REG documents.
The responsible office is required to respond to each applicable recommendation in the case study report. To date AE00 case studics have included about 120 recommendatiog . The-status of each recommendation is 2 .
e independently tracked and documented in A'E00's Annual Report. As of December 31, 1991, 15 AE0D recommendations were still unresolved. AE00's tracking' system ensures that each formal AE0D recommendation is tracked until a resolution is achieved.
The majority of the active issues identified in AE00 case studies have been p' assigned a high priority and many are included in the NRC's Generic Safety Issues program. In addition to implementing the formal recommendations. that are tracked and -listed in the AE00 Annual Report, NRC program offices.
routinely implement additional actions that are based on suggestions that are included in AE0D engineering evaluations or other AE00 reports.- AE00 does not formally track the actions taken in connection with AE0D suggestions.
AE0D "special studies" provide an accelerated documentation of AE00 operational experience assessments. Special studies contain suggestions or recommendations for regulatory actions that are to be completed expeditiously.
The need for peer review is determined on a case-by-case basis. To date AE00-has issued 37 special study reports.
AE0D " engineering evaluations" provide assessments of significant operating events and, if appropriate, contain suggestions for remedial action. To date AE0D has issued over 230 engineering evaluation reports. Many engineering evaluation reports contain AE00 suggestions for NRC followup action or feed back correspondence such as NRC information notices.
AE00 " technical reviews" are studies that are ultimately vie.'ed by AE00 as involving an issue having limited safety significance. These reports typically conclude that the planned or- scheduled-corrective actions of the licensee or the industry are adequate. To date AE00 has issued about 175 technical review reports.
As a result of AE0D reports, 10 NRC bulletins and.approximately:140 NRC information notices have been issued. -These-reports were considered in forming the regulatory basis for four NRC generic letters and nine NRC generic issues. They also contributed new safety-information for 11 ongoing generic-issues and 5 unresolved safety issues.
Examples of AE00 Studies As a result of AE00 studies,- utilities have taken actions-to improve safety.
Some examples follow.
(1) LaSalle Power Oscillation Event (Special- Study S803)
On March 9,1988, LaSalle Unit 2 experienced unexpected high amplitude reactor power oscillations. The operators failed to scram the reactor quickly. A review of incident: reporting system (IRS) reports indicated that similar events had occurred at foreign plants. In addition to the issues of operator action and training, such as demonstrating that guidance.and training for operators regarding oscillations was weak, AE00 raised several other issues, such as uncertainties about boiling-water 3
reactor (BWR) thermal' limits, anticipated-transient without-scram (ATWS) mitigation, prior resolution of Generic Issues B-19 (Thermal-Hydraulit Stability) and B-59 (N Loop Operation _in BWRs and PWRs), and compliance with General Design Criterion 12 (Suppression of Reactor Power Oscillations). AEOD recommended that a bulletin be issued to allow continued safe -
operation while NRC and industry investigated the issues and refined associated analytical methods so that operating conditions likely to cause instabilities would be avoided and that operators would be trained to better cope with-such situations. Industry has responded by submitting NED0-31960,-
"BWR Owners' Group Long-Term Stability Solutions Licensing =
Methodology," and its supplement. Additionally, a report entitled "ATWS Rule issues Relative to BWR Thermal-Hydraulic Stability" was issued. The BWR 0wners Group is continuing to evaluate mitigative actions. These actions include both emergency procedure guidelines changes and automatic protective actions (i.e., reactor scram or selective control rod insertion).
(2) Air Systems Problems at U.S. Liaht Water Reactors. NUREG-127L 191. 2 (Case Study C701) ,
AE00's continued review of operating experience focused on air-systems problems. In March 1987 AE00 issued a case study that was published in December 1987 as NUREG-1275, Vol. 2. The study q highlighted failures of safety-related systems that resulted from degraded or malfunctioning instrument air systems. ' As-a -
result of this study, NRC issued Generic letter 88-14. Most-nuclear power plants found instrument air system problems that could have affected safe plant operation. Acccrdingly, most-licensees have taken appropriate corrective actions. The Electric-Power Research Institute (EPRI)-initiated air system workshops and asked AE00 to make presentations. Recently, - the nuclear industry formed an air-operated valve user's group and asked AEOD to participate. Review of recent operating; experience-has shown that actions taken by the industry have been effective in reducing the-risk from air system problems, i.e., the failure rate of pneumatic valves has decreased.
(3) Operatina Experience Feedback Renort - Solenoid Operated Valve Etpblems at U.S. tioht Water Reactors. NUREG-1275. Vol. 6 (Case Study C90-01)
In 1988 NRC management noted that solenoid-operated valve (SOV)-
failures were occurring often in the industry, thus reducing the
~
level of safety. AE00 was requested to perform a study on S0Vs to determine if there was a generic problem. The case study was published in February 1991 as NUREG-1275, Vol. 6. The study indicated that many events involving common-mode.SOV failures or the potential for common-mode failures affected safety systems.
As a result of this study, NRC issued Generic Letter 91-15 in 4
September 1991. -The EPRI Nuclear Maintenance Assistance Center (NMAC) prepared an S0Y maintenance guide, to which AE00 contributed in an advisory capacity, and organized-several; workshops-at which AE00 also participated.- Many manufacturers of S0Vs have modified their design and/or manufacturing process to eliminate problems identified in the study. The November 9, 1991, turbine overspeed event at Salem _may have been prevented '
if-the licensee had taken corrective actions on earlier S0V-failures at Salem or implemented some' of the recommendations listed in the report.
(4) Service Water System Failures and Dearadations in Licht Water-Reactors. NUREG-1275. Vol. 3 (Case Study C801)
Following continued reported operational problems at several utilities and because the issuance of generic communications.(by NRC and industry groups) did not appear _to have had an effect in -
reducing the frequency of service water systems problems, AE00:
initiated an in-depth study of service water systems failures and degradations. The review and evaluation focused on the identification of causes of service water system failures and degradations, the adequacy of corrective actions implemented and planned, and the safety significance of the operating events.
In the case study, it was noted that service water system failures and degradation have significant safety implication, and that there was-a high frequency of these failures and degradations. The study con:luded that corrective action was warranted to reduce both the frecuency and consequences of service water system failures anc degradations.- The case- study.
was issued as NUREG-1275, Vol. 3, in November _-1988.
Subsequently, a generic letter (Gk 89-13) was_ issued.in 1989.
-(5) Operatina Experience Feedback Report - Proaress in Scram Reduction. NUREG-1275. Vol. 5 AE0D performed a detailed study of:the progress made by the nuclear power industry in a reactor trip reduction program.' The results of this study were discussed in two AE00 reports:
NUREG-1275, Vol . 5, published--in March 1989, analyzed unplanned -
reactor trip data for the period between January 1, 1984, through December 31, 1987, and NUREG-1275, Vol. 5, Addendum,-
issued in August 1989, analyzed the unplanned reactor trip data.
between January 1, 1988, and March 31, 1989. Tho study found that the number of unplanned reactor trips- per year had declined continuously since 1985. This decreasing trend was observed one year after initial efforts to systematically track the trend in U.S. light-water reactor (LWR) unplanned trips' were. begun. .0ne of the principal contributions to the improved trend was a-reduction in__the number of trips initiated by problems in the main feedwater system. This area had received a great deal _of 5
attention under the reactor trip reduction programs conducted by the nuclear steam supply system (NSSS) vendors.
(6) Operational Experiences at Newly licensed Nuclear Power Planth NUREG-1275. Vol, 1 In 1987, AE0D performed a study of the first two years of operation of commercial nuclear power reactors, ' Operational Experience at Newly Licensed Plants," NUREG-1275, Vol.1. The study focused on the startup ex)erience of 22 plants for which operating licenses were issued 3etween 1983 and 1986 and analyzed data drawn from operational reports and site visits' to 11 of these plants. The analyses showed that, without early corrective action, the root causes of events that occurred-during startup would likely persist and cause :similar problems during early commercial operation. The study = concluded that it was possible to achieve significant -improvements in learning -
curves and early plant performance and made suggestions concerning plant management, personnel training, plant equipment, and some NRC practices.
Human Performance Studies Since 1983, AE00 has conducted independent assessments of human performance at licensed facilities. In 1983 AE00 conducted a special study of loss of safety system function events resulting from human errors involving operation of an incorrect unit or train. The results of the study were published in January 1984 in Special Study Report AE0D/S401, " Human Error in Events Involving.-Wror.g Unit or Wrong Train." Several actions were taken at that time, including the issuance of Information Notice (IN) 84-51, " Independent Verification," and IN 84-85, " Inadequate Defeat of-Safety Function Caused by Error involving Wrong Unit, Wrong Train, or Wrong System." AE0D continued to study these '
types of events and issued report (AE0D/S401) supplements on August 8,1984, February 13, 1986, and~ September 19, 1986. In addition, AE0D worked with NRR in a joint study to perform onsite investigations of events _that involve actions on the wrong unit, train, or component at 10 multi-unit reactor sites.
The results of the joint study were published April '1986 in NUREG-1192,'"An Investigation of the Contributors to Wrong ~ Unit _or Wrong Train Events."
In 1985 AE00 conducted.a study of events that resulted in a total . loss of safety system function. Although the study identified 133 losses of safety system function, the major focus of the analysis was on-the 87 events (65 percent of the total) that were the-result of human factors contributions, such.as personnel errors. The results of the study were: published-December 30, 1985s in AE0D Case Study C504, " Loss of Safety: System Function Events."
In-1990 AE00 initiated a program to study the effect of human performance during selected oower reactor events. The studies conducted within the program are -intended to identify factors that helped or. hindered operator performance. Emphasis is on improved _ understanding of operator performance rather than verifying-compliance with NRC regulations. A report has been-6 l-y
t 4
issued for each site visited or event studied. To date, AE0D has conducted 16 human performance studies,-representing a wide variety of events at pressurized-water reactors (PWRs) and BWRs. The studied events have-occurred during both power operation and shutdown conditions.- The factors addressed have included control-room staffing and organization, the " dual _ role" shift technical advisor, use of shift resources during an emergency, operator control of engineered safety features, simulator training, crew teamwork during high stress situations, task awareness, knowledge-based operator performance, use of procedures, and licensee followup events. Study findings have provided many examples of good industry practices that could be applied-to improve human performance. One example was Fort Calhoun's control room organization and the division of duties and responsibilities of the control-room staff.
Performance Indicators Since May 1986, AE00 has participated in an interoffice task group to_ develop an NRC program using quantitative. indications of nuclear power plant safety performance. Initial development resporibility was assigned to the former Office of Inspection and Enforcement. The Performance Indicator (PI) Program became operational in 1986. In 1987, as-part of the NRC's reorganization, responsibility for management of the P1 Program was transferred to AE00.
The Pl Program includes seven indicators that have been validated as a set to have some correlation with iftensee performances measured by the systematic-assessment of licensee perfcrmance (SALP). The seven indicators are automatic scrams while critical, significant events, equipment-forced outages per 1000-critical hours, collective radiation exposures, sefety-system fail?res, safety-system actuation, and forced-outage rate. An eighth indicator displays information related to the cause of events reported at nuclear power plants.
In addition to the quarterly publication of-PIs, AE0D independently analyzes the Pls to identify licenses whose performance trends may warrant in-depth analyses. These analyses include events reported to the NRC pursuant; to 10 CFR 50.73 to determine the underlying causes of licensee performance. The results of these analyses are compared with incident investigation team and-augmented -inspection team results, abnormal _ occurrence reports,. accident sequence precursor events, and SALP scores. These__ comparisons-are conducted to obtain an overall understanding of licensee strengths.and weaknesses. AEOD~
uses these plant assessments in preparation for the NRC semiannual Senior Management Meetings (SMM). AE0D's independent perspective and input into the process for recommending plants to be discussed at the SMMs is derived principally from AE00's plant assessments based on _the PI Program results.
Accident'Seauence Precursor Proaram
~
The ASP Program was established at the Nuclear Operations Analysis Center at Oak Ridge. National Laboratory under the direction of the Office of Nuclear Regulatory Research (RES) in the summer of 1979. The first major report of the Program was published in June 1982 and received extensive review. The ASP:
Program was transferred to AE00 in 1985.
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AEOD analyzes selected operating events using the ASP process to gain insight into events and improve-understanding of them from a risk perspective. The ASP process quantitatively evaluates operational experience as a complement to performance indicators, with a systematic methodology that integrates actual initiating everts, plant conditions, and the reliability of standby safety eqdipment into an overall quantitative assessment, which is expressed as the conditional core damage probability.
All LERs and sulected other events are screened for significance in the ASP-process. While supplementing other agency event screening activities, this process is separate and independent from those activities. This process ensures that LER evaluations are consistently and comprehensively performed, i The 1991 ASP analyses revealed events that might not otherwise have been _
recognized as important events. Without the ASP analyses, the agency might have continued to be unaware of the importance of such events and adequate regulatory action might not have been taken.
One example of an event, that was " revealed" by the ASP Program, occurred at 3 Shearon Harris on April 3, 1991. In this event, two alternate miniflow relief valves and associated piping in the high-pressure injection system were found _.
to have failed. If the high-pressure injection system had been called upon to mitigate a small break loss of coolant accident, the system function would have been seriously degraded and may have failed. j AE0D Annual Report (NUREG-1272)
To provide feedback on operational experience, AE00 issues a two-part annual report (NUREG-1272) to describe its activities performed during-the previous year. Part I covers reactor facilities and represents an overview of .i operating experience of the nuclear power industry from the AE0D perspective,- ,
including comments about trends of some key performance measures. The report j also incudes the principal findings and issues identified in AE00 studies over ,
the past year and summarizes information from such sources as LERs, diagnostic !
evaluations, and reports to the NRC's Operations Center. . Part 2 covers nonreactor facilities and presents a review of the events and concerns associated with the use of licensed material in nonreactor applications, such as personnel overexposures and medical misadministrations. The reports discuss the Incident Investigation Program and summarizes both the IIT.and.AIT reports issued during that calendar year. The status of NRC staff actions for events investigated by IITs is also included in the reports.
O_ther AE0D Activities .
AE00 is also involved in the following: j (1) Identification of operational data needed to. support safety analyses, and development of agency-wide reporting of operational data and the methods and systems to retrieve these data.
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. 1 (2) Development of a coordinated system for feedback of operational ;
safety information to NRC offices, licensees, and other organizations, as appropriate, and preparation of the quarterly
' Abnormal Occurrence Report to Congress." r (3) Tracking the recommendations and staff actions contained in the AE00 studies and Ili reports. Generic staff actions from the i DET reports also.are tracked. The appropriate NRC program office or regional office (as assigned) acts on these recommendations and actions and is responsible for resolving them.
(4) Acting as a focal point for coordination of generic operational :
safety information and data systems with industry, foreign-governments, and other agencies involved with the collection, analysis, and feedback of operational data. ,
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ENCLOSVRE 2 INCIDENT INVESTIGATIONS Backaround_
In 1985 Congress required the NRC to conduct a study, to be submitted to Congress, on the need for and feasibility of an independent organization +
responsible for conducting investigations of safety significant events and incidents at facilities licensed by the NRC. On June 10, 1985, in response to a study conducted for the NRC by the Brookhaven National Laboratory (BNL),
the staff recommended (SECY 85 208) changes to the NRC's program for the investigation of significant operational events through establishment of an NRCincidentInvestigationProgram(llP).
In October 1985 the Commission approved establishment of the ilP and assigned .
overall program development and administrative responsibilities to AEOD.
Commission approval of the llP represented the culmination of several years of-study and discussion within the NPC staff and the Commission on the -
appropriate objectives, reporting level, and organizational responsibilities for an NRC IIP. AEOD was assigned lead responsibility for development and administration of the IIP with support from the regions and headnuarters offices. 1 Incident investiaation Proaram t
The llP is described in NRC Management Directive (MD) 8.3.."NRC incident Investigation Program." The purpose of the IIP is to ensure-that serious operational events at facilities licensed by the NRC aro investigated in a timely, objective, systematic, and technically sound manner; the arobabic cause(s) are determined; and the factual information related to tie events is documented. The llP also ensures that the facts, conditions, circumstances, and probable causes related to the event are promptly disseminated and that appropriate followup actions are identified. The llP thereby increases the effectiveness of the NRC's regulatory programs as well as licensee operations.
Iho llP also improves the NRC s regulatory oversight of. licensee activities through the discovery of facts- that could show whether the regulatory process before the event contributed directly to the cause or the course of the event.
Events within_the scope of the llP may involve responses by either an Executive Director for Operations (ED0)-established incident investigation team (IIT) or the regional level augmented inspection team (AIT).
AE00 administers the llP, with the assistance of other NRC offices, to meet program objectives. AE0D maintains the " Incident Investigation Manual" (NUREG-1303) and Management Directive, MD 8.3, "NRC Incident Investigation Program," which contains procedures governing the conduct of IITs. AE00 provides periodic training on the llP and IIT methods to ensure that NRC staff on the EDO approved IIT rosters are qualified to serve on llTs. AE00 also 10
maintains the rosters and identifies and provides staff to be members and/or leaders of Ilis and Alis. . The regional offices implemein the AIT portion of the llP. ,
AE0D's independent role in the implementation of the llP begins with its '
, routine screening, review and assessment of operational events reported to the NRC. Upon notification of a significant operational event, the Directors of i NRR or NHSS, AE0D and the Regional Administrator jointly discus and assess the a safety significance of the event to determine whether an lli or an All is -
required. Regional Administrators, in coordination with NRR or NHSS, .
determine those operational events warranting investigation by an Ali. -As soon as it becomes clear that at least an AIT is warranted, preferably before an All is actually established, the Directors of NRR or NMSS, and AE00 to consider whether an 111 response is appropriate. If.an 111 is agreed upon, the initiating office makes that recommendation to the EDO. Differences among offices concerning whether an AIT or llT is the proper response are submitted to the C00 for resolution. Normally a consensus is achieved among the involved offices regarding the appropriate-responso (e.g., AIT.or llT).
However, a consensus is not required and the director of the responsible .
program of fice, the involved regional administrator, or the Director of AE00 may individually recommend to the EDO that an 111 be established. in this ,
way, AE00 provides an oversight function in assessing the appropriate _ agency response to significant events at NRC licensed facilities.
If the LDO decides to establish an IIT, AE00 will initiate activities in support the ED0's decision. These include preparing a proposed IIT. charter and identifying ?otential lli members. This is accomplished in coordination .
and support of 11e regional and headquarters offices. . AE00 also arranges for :
administrative support for the llT. Additionally, AE00 informs the Institute- .
of Nuclear Power Operations (INPO) that an !!T has been established and requests an industry participant. As required, AEOD will arrange for contractor services to support the !!T in cases where needed expertise is not available within the staff or industry. AE00 screens each candidate to ensure-that they have no significant recent involvement in the licensing, inspection, enforcement, or eperational activities of the facility. AE0D's primary objectives are to ensure that the mission of the !!T is clearly and ,
objectively defined and its members are technically qualified and free of any potential regulatory or technical bias. .
AEOD also contacts and informs the Inspector General (IG) that an IIT has'been established to allow an IG representative to observe and participate in:lli activities at the site, should they choose.to do so. In this.way the IG representative is available to immediately followup on any evidence or information.under the purview of IG: investigatory responsibilities. _
Once an llT has been established, AE00 provides support to the Ili leader on .
procedural matters regarding the-conduct _of the investigation.- AE00's role is to provide advice and counsel _ as may be needed to achieve a timely, thorough,- '
systematic, and independent investigation. AE00's objective is to ensure that sufficient factual information and evidence are collected,. analyzed, and-documented to determine the probable causes, conditions, and-circumstances l
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,ertatning to the event. This generally involves direct communications
/>eiwun tfie Director, AE00, and the IIT leader; providing the team with AEOD ,
support staff having expert knowledge in llT administrations and providing an AE0D technical ttaff member who is knowledgeable-in incident investigation methods and practices.
After the llT onsite investigation is completed and preparation of the llT report has begun, AE00 provides oversight as needed, to the IIT leader regarding completeness of the report. The Director, AEOD independently reviews the report to ensure that all required elements, as described in the llP Manual, have been addressed. The AE0D Director's review also ensures that the factual information that was collected or resulted from analysis, and is needed to support the findings and conclusions, is documented in the report. '
When the report is complete, the Director, AE00, forwards it to the EDO for ap)roval. The report is submitted to the EDO without prior review by any ional office. The Director, AE00, also assists oiler NRC headquarters the !!T leader in preparingor reg {he Commission briefing on the results of the investigation. .
After the Commission has been briefed on the results of the investigation and the report is made public, AE00 supports the EDO in the development of NRC followup actions to address the !!T's findings and conclusions. AEOD independently drafts proposed industry generic and plant-specific followu) actions to address the findings and conclusions. AE00 coordinates with tie
!!T leader to ensure a clear and comprehensive understanding of the team's.
findings and conclusions and coordinates with the responsible headquarter office (s) and the affected regional office to ensure that the draf t followup staff actions are assigned to the appropriate office (s). Following these reviews the proposed NRC actions are forwarded to the EDO who makes the final assignments. For AIT's at power reactors, AE00 independently reviews each AIT report to identify potential lessons for feedback in NRC generic-communications and for possible inclusion in ongoing or potentially new AE00 studies.
After the followup actions are assigned, AE00 monitors the status of each staff action until final resolution. In this way AE00 ensures that the- '.
regional or headquarters office plans for resolving each item is taken to completion. The status of each open staff action item, including those assigned to AE00, are documented in the AE0D Annual Report. If requested by the EDO, AE0D will independently assess the adequacy of the actions taken by the assigned region or program office to address the IIT finding and/or assigned followup action.
Since the llP was established in 1985, seven llTs have been established by the EDO and su) ported by AE00. These are listed in Table 1 below. As shown in Table 1, tiere have been a total of five events at power reactor facilities and two at non-power reactor facilities in four of the NRC's five regions.
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Table 1. Completed incident Investigations DJLt Operational Event Description .i 1785 " Loss of Main and Auxiliary feedwater Event at the Davis-Besso PIar.t on June 9, 1985" (NUREG-1154) ;
1985 " Partial Loss of In Plant Electrical Power and Feedwater Hammer, November 21, 1985" (NUREG-1190) 1
, 1985 " Loss of Integrated Control System Power and Overcooling :
Transient at Rancho Seco on December 26, 1985" (NUREG-1195) .l 1990 " Inadvertent Shipment of a Radiographic Source from Korea to' Amersham Corporation, Burlington, MA." (NUREG-1405) i 1990 " Loss of Vital AC Power and the Residual Heat Removal System ;
during Mid Loop 0perations at Vogtle Unit 1 on March 20, 1990" (NUREG-1410) 1991 " Potential Criticality Accident at the General Electric Nuclear +
Fuel and Component Manufacturing facility, May 29, 1991" (NUREG-t 1450) 1991 " Transformer failure and Common-Mode Loss of Instrument Power at Nine Mile Point Unit 2 on August 13, 1991" (NUREG-1455) . i Additionally, as shown in Table 2 through November 1992, there have been 90 AITs established since 1986.
Table 2. Augmented Inspection Teams i Number and Type of Facility Year Egg JMli Q1hgt Total / Year 1986 3 5 2 10-1987 8 6 1 15.
1988 3 6 1 10 1989- 12 7 0 19 1990 6 3 0 9 1991 11 4 0 15 ,
1992*' l. 1 2 .11 Totals *' 48 36 6 90'
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4 fiumerous IIRC staff actions have been assigned as a result of completed Ills.
These have involved plant-specific technical issues,11RC program weaknesses, and potentially generic issues. These actions have also involved issues regarding potential weaknesses in flRC's rules and regulations, regulatory guidance, staf f review standards, or program in;plementation.
Generic technical lessons identified by llis have included auxillary feedwater system and motor operated valve reliability check valve reliability. plant transients caused by liabcock & Wilcox (ll&W)-integrated control system failures, shutdown risk management, and criticality safety controls.
Regulatory process lessons identified f rem events invesilgated by llis include the need for more timely, systematic, ! ov eviews of operating plant performance, which eventually resulted m ;' lL Sent of the f4RC's semiannual review of plant perfo,mance, % w" a e rigorous design- _
analysis, diagnostic testing and configt a W6 for safety related motor operated valves; the need for improvd .
coma.unnation between plant and the f1RC response organizations; the need fo,* in reased regulatory attention to plant operation during shutdown and low power conditions; and the need for improved event reporting and improved likC materials licensing and inspection processes.
Regulatory oversight lessons identified from events investigated by 1115 have resulted in new, revised or proposed flRC regulations (e.g.,10 CfR Part 55, requiring site specific simulators), changas to regulator) guides (e.g.,
regulatory guide 3.67, " Standard format and Content for Emergency Plans for fuel Cycle and Materials facilities"), Standard Review Plans, (e.g., " Safety Operability Specifications for Radiation and fluclear Safety Instruments and Controls"), in addition, fiVREG 1324, " Proposed Method for Regulating Major Materials Licensees," was issued in february 1992, in response to regulatory weaknesses identified by the til at the General Electric fuels facility in Wilmington, North Carolina, in June 1991. The 14UREG made recommendations for improvements in six areas ~(1) licensing activities, (2) inspection activities, (3) regulations, (4) organization of the liMSS and NRC staff, (5) training for -
the llRC staff, and (6) the National Program Review.
Overall, Ills have been highly effective in leading to a large number of significant technical lessons involving plant-specific and generic NRC actions. In addition, lils have significantly contributed to the identification of potential weaknesses in tiRC programs and regulatory oversight.
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ENCLOSVRE] l 1
DIAGNOSTIC EVALVATIONS Backaround in August 1986, former Chairman Zech proposed the formation of a new type of NRC evaluation and assessment capability that could be used to independently assess the performance of a plant if other indicators, e.g., systematic assessment of licensee performance (SALP) and performance indicator (PI) analysis indicated that such a assessment would be appropriate. In September 1986 the staff proposed a new Diagnostic Evaluation Program (DEP) in the Office of Inspection and Enforcement (IE) in response to Chairman Zech's i
proposal. On November 24, 1986, the Chairman approved the staff's proposal to develop the new evaluation capability as a new NRC program.
Commission approval of the DEP represented the culmination of several months of study and discussion within the NRC staff and the Commission on the approariate objectives, reporting level, and organizational responsibilities for tie program. AE0D was assigned lead responsibility in May 1987 for development, direction, and administration of the DEP to meet program objectives, with assistance from the regional and headquarters program offices.
Diannostic Evaluation Pronram The DEP is structured to provide an independent assessment of licensee performance and a determination of root cause(s) of safety performance problems. The DEP also augments information_ provided by the SALP Program, the Performance Indicator (P1) Program, and the various_ inspections performed by the NRC headquarters and regional offices. The assessment is independent in the sense that the administration and management of the program are independent of the licensing, inspection, and enforcement processes and team members have no significant recent involvement with the licensee such as licensing, inspection, enforcement or operational activities.
The DEP is presently governed by NRC Hanagement Directive (MD) 8.7, "NRC Diagnostic Evaluation Program " and by diagnostic evaluation team (DET)
Guidelines. AE0D establishes and maintains the core capability for DETs in the Diagnostic Evaluation and incident Investigation Branch (DEllB) and also develops and maintains procedures governing the DETs in the-DET Guidelines.
AE0D's role in the implementation _of the DEP begins with'its Operational Experience Assessment Program discussed in Enclosure 1. . AE00 assists the-
! Office of Nuclear Reactor Regulation (NRR) and the regions in monitoring I licensee performance and recommends to the EDO, in coordination with the l
Director, NRR, and the appropriate regional administrator, reactor facilities o that may warrant a Diagnostic Evaluation (DE). The EDO selects those facilities that are to receive a DE on the basis of recommendations from the-NRC senior managers, including the Director, AE0D. In this way AE0D provides 15 L
I an independent perspective in the agency's assessment of performance issues at NRC-licensed facilities.
AE00 establishes and maintains rosters of potential DET managers and team members, compiled with the concurrence of headquarters office directors and regional administrators, and provides appropriate training. When the EDO makes the decision to establish a DE, ALOD initiates a number of activities.
These activities include recommending personnel to be assigned as the DET manager and as team members, and proposing a site specific evaluation plan.
These activities are coordinated with the appropriate headquarters office (s) and regional administrator. The DET will include a core of team members and functional area leaders from DEllB, supplemented with experienced regional inspectors, experienced NRC technical staff members, and contractors, as appropriate. To maintain inde3endence, AE00 screens each potential DET manager and member to ensure t1at they have had no significant recent involvement in licensing, inspection, enforcement or operational activities at the selected facility. AE00 also arranges for administrative support for the DET and provides training for the DET during the planning and preparations phase.
The scope of a DE is broad and performance based. des may include any aspect of the licensee's safety performance and independently develop findings, conclusions, and root causes.. This enhances the credibility, utility and impact of the team's findings and conclusions. This is particularly important in the event that DET findings and conclusions differ from other NRC data or conclusions. The EDO originally approves the areas to be evaluated at the selected facility, however, the DET manager has the latitude to revise the scope and areas of emphasis of the ongoing evaluation on the basis of initial findings.
After the DET onsite evaluation is completed and preparation of the DET report has begun, AEOD provides oversight as needed, to the DE1 manager regarding completeness of the report. The Director, AEOD, independently reviews the report to ensure that all required elements, as described in the DEP Management Directive 8.7 and the DET Guidelines, have been addressed. When the DET report is complete, the Director, AE00, formally approves the report and forwards it to the EDO. The Director, AE00, also provides oversight and assistance to the DET manager in preparing the EDO briefing on the results of the DE.
The DET manager, in coordination with AEOD and the other program offices, draf ts proposed generic and plant specific staff followup staff actions to address the findings and conclusions documented in the DET report. The Director, AE00, reviews the staff actions to ensure all appropriate actions are proposed. The Director forwards the proposed NRC staff actions to the ED0 who makes the final assignments.
After the EDO followup staff actions are assigned, AE00 monitors the status of each generic action until final resolution. In this way, ALOD ensures that the regional or headquarters office plans for-resolving each generic item is 16 I
l taken to completion. The status of each open generic action item, including those assigned to AEOD, are documented in the AE00 Annual Report.
Since the DEP was established in 1986, 10 des and 1 s)ecial evaluation have been established by the EDO and supported by AE00. T1ese are summarized in Table below, j i
[.ompletei Diaanostic Evaluations ;
ElpjA V11111,y Renort Date i Dresden CECO Nov 1987 McGuire Duke Mar 1988 Turkey Point
- FP&L Juq 1988 fermi Deco Nov 1988 Perry CE! May 1989 Brunswick CP&L Jul 1989 Arkansas AP&L Dec 1989 Palo Verde APS Mar 1990 '
Zion Ceco Se) 1990 Oyster Creek GPUN fe) 1991 ,
fitzPatrick PASNY Dec 1991 :
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- Special evaluation.
Numerous NRC actions have been assigned as a result of completed DEls, t involving alant-specific technical issues, NRC programs, and potential generic
- issues. T,1ese actions also involve issues regarding potential weaknesses in NRC's rules and regulations, regulatory guidance, staff review standards, or NRC program implementation.-
des have identified root causes of problems with licensee performance not ,
normally detected by the day to day inspection program and SALP process.
Management issues such as strained resources, organizational instability, communications )roblems, and inadequate corporate oversight have been discovered by 11e DETs through the broad scope of the evaluation effort. In some instances, these fundamental problems were not highlighted by the inspection and licensing efforts, nor were they identified by the licensee.
Thus the diagnostic evaluation served to improve the licensee's understanding of its observed problems and facilitate its development of potentia 1>
solutions.
des also have identified root causes of problems that the licensee had not identified as part of its proposed improvement program. By evaluating the root.causes identified during DE, licensees have been more effective in ;
identifying missing or weak areas _in their proposed improvement programs.
Therefore, they have been able to make substantial improvements by developing more effective corrective action programs.
The DEP has also matured.in its: ability to assess the involvement and effectiveness of licensee management in ensuring safe plant operations. ,
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Comprehensive plans and methods for management and organizational evaluations have been developed and improved on the basis of the experience and insights gained from the earlier evaluations. This experience has allowed the NRC to better gage observed management effectiveness and practices in ensuring safe plant operations.
des also have identified programmatic problems with several of the facilities evaluated. The most prevalent programmatic weaknesses in the safety-related equipment area appear to involve motor operated valves and check valve programs. For many )lants, weaknesses in design basis information or understanding contri)uted to performance problems. The root cause analysis programs at most plants were also found to be weak. Many of the plants had significant backlogs of known problems that were awaiting engineering evaluation or corrective maintenance. The strain on resources that these backlogs imposed, coupled with a frequently insuf ficient design basis documentation, ineffective engineering support, and the absence of effective teamwork among station support 6partments, were often the major impediments to performance improvement.
des have identified isolated instances in which NRC staff implementation of regulatory programs needed additional attention. These issues included instances where the licensee's proposed ASME Section XI inservice test programs were not reviewed in a timely manner; additional duties assigned to a resident inspector resulted in his/her working an inordinate amount of overtime; assessments of licensee performance (SALP) were not consistent with actual performance; the licensee's response and regional followup to a confirmatory order should have been more rigorous; and safety related system deficiencies had been overlooked during initial licensing reviews. rrompt corrective actions were initiated by the regions and NRR when these issues were identified.
Frequently, des have identified safety issues of a plant-specific and generic nature requiring further followup by the NRC staff. These issues included inservice testing program deficiencies for check valves, inadequate minimum flow in centrifugal pumps, plant equipment degradation inside containment as a result of steam leaks within technical specification limits, and service water system degradation.
des have changed the NRC's perspective of plant performance problems. For example, four plants have been placed on the Problem Plant List either as result of the DE or as a result of a DE followup. Conversely, the DE at one plant found the plant safety performance to be better than previously thought.
Overall, des have been highly effective in assessing licensee performance and regulatory issues and providing feedback to the nuclear Ndustry and the regulatory process for corrective actions. These actic have involved both plant specific and generic technical issues and safety programs.
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