View source for NUREG-1715, Identical Letters - Request for Review of Reliability Study: NUREG-1715, Vol. X, Component Performance Study - Air-Operated Valves, 1987-1998 (Draft)

{{Adams
| number = ML003779504
| issue date = 12/14/2000
| title = Identical Letters - Request for Review of Reliability Study: NUREG-1715, Vol. X, Component Performance Study - Air-Operated Valves, 1987-1998 (Draft)
| author name = King T
| author affiliation = NRC/RES
| addressee name = Beedle R, Bischoff G, Drake A, Kelly J, Lang J, Lochbaum D, Marston T, Peifer M, Townsend D, Vine G
| addressee affiliation = ABB-CE Owners Group, Electric Power Research Institute (EPRI), Framatome Technologies, Inc, General Electric Co, Institute of Nuclear Power Operations (INPO), Nuclear Energy Institute (NEI), Union of Concerned Scientists, Westinghouse Electric Corp
| docket = 
| license number = 
| contact person = 
| document type = Letter type:NUREG
| page count = 14
}}

=Text=
{{#Wiki_filter:Mr. Mark A. Peifer Vice President and Director Industry and Government Relations Division Institute of Nuclear Power Operations 700 Galleria Parkway, NW Atlanta, GA 30339-5957

==Dear Mr. Peifer:==

==SUBJECT:==
REQUEST FOR REVIEW OF RELIABILITY STUDY: NUREG-1715, VOL. X, COMPONENT PERFORMANCE STUDY  AIR-OPERATED VALVES, 1987-1998 (DRAFT)
In accordance with our peer review process, we are offering you the opportunity to review and comment on the draft study NUREG-1715, Vol. X on the reliability of air-operated valves (AOVs) at U.S. commercial pressurized water reactors (PWRs) and boiling-water reactors (BWRs). This study documents an analysis of the performance of safety-related AOVs in the PWR and BWR risk-important (RI) systems.
This study is part of an on-going program of risk-based analysis of reactor operating experience. This effort was undertaken to systematically identify risk significant insights and provide feedback to the regulatory process. This study is also being used in the development of risk-based performance indicators that will be based to a large extent on plant-specific system and equipment performance.
This study provides an estimate of the air-operated valve unreliability based on Engineered Safety Features (ESF) actuations and surveillance test demands between 1987 and 1998. The report identifies dominant contributors to component unreliability and provides an evaluation of significant trends. In addition, this study includes a comparison with air-operated valve unreliability estimates published in probabilistic risk assessments (PRAs) and individual plant examinations (IPEs).
Significant findings from this study are as follows:
* Probability of failure on demand. The AOV probability of failure on demand estimates developed in this report for the PWR and BWR RI systems are consistent with the generic value range from NUREG/CR-4550 (which provided the input to the NUREG-1150 analyses), except the PWR RHR system mean value (5.2E-4) is significantly lower than the NUREG/CR-4550 mean value. The generic and calculated probability values are as follows:

2 LOWER                      UPPER BOUND       MEAN           BOUND NUREG/CR-4550                                    5.4E-3      2E-3           4.8E-3 PWR RI SYSTEMS auxiliary feedwater (AFW)                        4.6E-6      1.8E-3         6.9E-3 high pressure injection (HPI)                    4.8E-6      1.2E-3         4.7E-3 residual heat removal (RHR)                      6.1E-5      5.2E-4         1.3E-2 chemical and volume control system (CVCS)        3.5E-7      3.4E-3         1.5E-2 component cooling water (CCW)                    6.7E-5      5.8E-3         2.1E-2 BWR RI SYSTEMS reactor core isolation cooling (RCIC)            3.5E-4      3.0E-3         7.7E-3 high pressure coolant injection (HPCI)           4.3E-4      3.6E-3         9.5E-3 low pressure core spray (LPCS)                   2.9E-15     2.1E-3         1.2E-2
* Failure rate trends. Failure rates, as a function of component-years, were compared among the PWR plant age groups (3 groups of approximately equal size from older to newer plants by commercial operation date). For PWRs, the review of plant age groups did not show evidence of increasingly higher failure rates for any plant age group due to aging mechanisms. For BWRs, failure data was too sparse for trending failure rates.
* Common-cause failures. The number of complete AOV common-cause failures (CCF) identified in this report is consistent with the expected number based on the CCF database parameters for the combined PWR and BWR complete failure population used in this report.
The technical insights that support this goal include:
* Leading contributors to failure. The evaluation of PWR AOV subcomponent (e.g., valve body and pneumatic operator) failure patterns demonstrated that failures of pneumatic-operator subcomponents were the biggest contributors (greater than three-fourths) to AOV failures. BWR AOVs also showed that valve operators were the biggest contributor, although the number of failures (6) was sparse.
* Failure trends. For the PWR RI systems during the 1987-1995 period, there was no discernible failure trend. For BWR RI systems, no trending was determined due to sparsity of failure data.
* Failure causes. Failure of AOVs in PWR RI systems was mainly due to age/wear causes (47%).
* Probability of failure on demand. The AOV mean probabilities of failure on demand used in plant-specific IPE studies were compared with the results of this report. The PWR IPE mean values were generally consistent with the results of this report and the NUREG/CR-4550 generic values. No comparison was made with BWR IPE mean values as few BWR plants IPEs provided AOV failure probabilities on demand.

3 We are specifically interested in your comments regarding the technical adequacy of the modeling and data analysis and the appropriateness of the risk-important findings and conclusions. To meet our planned publication schedule, we would appreciate receiving your comments within 60 days of your receipt of this letter.
The Office of Nuclear Regulatory Research plans to update these and other related studies on a regular basis. These updates will continue our support of the NRC commitment to use operating experience in risk-informed regulatory activities.
A copy of this draft report and letter are being placed in the Public Document Room, NRC Headquarters, 11555 Rockville Pike, Rockville, MD, 20852. If you have any questions related to this report, please contact Mr. James R. Houghton of my staff at 301-415-6353 or e-mail at jrh2@nrc.gov.
Sincerely, Thomas L. King, Director Division of Risk Analysis and Applications Office of Nuclear Regulatory Research

==Attachment:==
As stated cc w/o att:
A. Thadani, RES M. Federline, RES S. Collins, NRR R. Zimmerman, NRR B. Sheron, NRR J. R. Johnson, NRR

4 IDENTICAL LETTERS DATED: /                                      /00

==SUBJECT:==
REQUEST FOR REVIEW OF RELIABILITY STUDY: NUREG-1715, VOL. X, COMPONENT PERFORMANCE STUDY  AIR-OPERATED VALVES, 1987-1998 (DRAFT)
DISTRIBUTION w/o attch:
OERAB RF                    DRAA RF                      File Center                     Public                   CPaperiello, DEDMRS IDENTICAL LETTERS Mr. Mark A. Peifer                                                          Mr. Ralph E. Beedle Vice President and Director                                                 Nuclear Energy Institute Industry and Government Relations Division                                  1776 I Street, N.W.
Institute of Nuclear Power Operations                                       Suite 400 700 Galleria Parkway, NW                                                    Washington, DC 20006-3708 Atlanta, GA 30339-5957 Dr. Theodore U. Marston                                                     Mr. James Lang Vice President and Chief Nuclear Officer                                    Director Electric Power Research Institute                                           Electric Power Research Institute 3412 Hillview Avenue                                                        1300 W. T. Harris Blvd.
Palo Alto, CA 94304                                                         Charlotte, NC 28262 Mr. Gary Vine                                                               Mr. David A. Lochbaum Sr. Washington Presentative                                                 Union of Concerned Scientists Electric Power Research Institute                                           1616 P Street, N.W.
2000 L Street, N.W.                                                         Suite 310 Suite 805                                                                   Washington, D.C. 20036-1495 Washington, DC 20036 Mr. J.J. Kelly, Manager                                                     Mr. Andrew P. Drake, Project Manager B&W Owners Group Services                                                   Westinghouse Owners Group Framatome Technologies, Inc.                                                Westinghouse Electric Corporation P.O. Box 10935                                                              Mail Stop ECE 5-16 Lynchburg, VA 24506-0935                                                    P.O. Box 355 Pittsburgh, PA 15230-0355 Mr. Dennis Townsend                                                         ABB Combustion Engineering Owners Group General Electric Nuclear Energy Owners Group                                c/o Gordon Bischoff, CEOG Project Manager GE Nuclear Energy                                                           M.S. 9615-1932 175 Curtner Avenue                                                          2000 Day Hill Road M/C 187                                                                     Windsor, CT 06095 San Jose, CA 95125 DOCUMENT NAME: S\DRAA.OERAB\JRH\EXTRA.LTR.WPD OAR in ADAMS? (Y or N) N                  ADAMS ACCESSION NO.: ML003779504                               TEMPLATE NO. RES-006 Publicly Available? (Y or N) Y                     DATE OF RELEASE TO PUBLIC                                         SENSITIVE?
To receive a copy of this document, indicate in the box: "C" = Copy without attachment/enclosure "E" = Copy with attachment/enclosure "N" = No copy OFFICE OERAB                               E        OERAB                       E OERAB                                    DRAA/D NAME JHoughton                                      SMays                              PBaranowsky                         TKing DATE                / /00                              / /00                              / /00                               / /00 OFFICIAL RECORD COPY (RES File Code) RES 2C-3

Mr. Ralph E. Beedle Nuclear Energy Institute 1776 I Street, NW Suite 400 Washington, DC 200006-3708

==Dear Mr. Beedle:==

==SUBJECT:==
REQUEST FOR REVIEW OF RELIABILITY STUDY: NUREG-1715, VOL. X, COMPONENT PERFORMANCE STUDY  AIR-OPERATED VALVES, 1987-1998 (DRAFT)
In accordance with our peer review process, we are offering you the opportunity to review and comment on the draft study NUREG-1715, Vol. X on the reliability of air-operated valves (AOVs) at U.S. commercial pressurized water reactors (PWRs) and boiling-water reactors (BWRs). This study documents an analysis of the performance of safety-related AOVs in the PWR and BWR risk-important (RI) systems.
This study is part of an on-going program of risk-based analysis of reactor operating experience. This effort was undertaken to systematically identify risk significant insights and provide feedback to the regulatory process. This study is also being used in the development of risk-based performance indicators that will be based to a large extent on plant-specific system and equipment performance.
This study provides an estimate of the air-operated valve unreliability based on Engineered Safety Features (ESF) actuations and surveillance test demands between 1987 and 1998. The report identifies dominant contributors to component unreliability and provides an evaluation of significant trends. In addition, this study includes a comparison with air-operated valve unreliability estimates published in probabilistic risk assessments (PRAs) and individual plant examinations (IPEs).
Significant findings from this study are as follows:
* Probability of failure on demand. The AOV probability of failure on demand estimates developed in this report for the PWR and BWR RI systems are consistent with the generic value range from NUREG/CR-4550 (which provided the input to the NUREG-1150 analyses), except the PWR RHR system mean value (5.2E-4) is significantly lower than the NUREG/CR-4550 mean value. The generic and calculated probability values are as follows:

Dr. Theodore U. Marston Vice President and Chief Nuclear Officer Electric Power Research Institute 3412 Hillview Avenue Palo Alto, CA 94304

==Dear Dr. Marston:==

==SUBJECT:==
REQUEST FOR REVIEW OF RELIABILITY STUDY: NUREG-1715, VOL. X, COMPONENT PERFORMANCE STUDY  AIR-OPERATED VALVES, 1987-1998 (DRAFT)
In accordance with our peer review process, we are offering you the opportunity to review and comment on the draft study NUREG-1715, Vol. X on the reliability of air-operated valves (AOVs)at U.S. commercial pressurized water reactors (PWRs) and boiling-water reactors (BWRs). This study documents an analysis of the performance of safety-related AOVs in the PWR and BWR risk-important (RI) systems.
This study is part of an on-going program of risk-based analysis of reactor operating experience. This effort was undertaken to systematically identify risk significant insights and provide feedback to the regulatory process. This study is also being used in the development of risk-based performance indicators that will be based to a large extent on plant-specific system and equipment performance.
This study provides an estimate of the air-operated valve unreliability based on Engineered Safety Features (ESF) actuations and surveillance test demands between 1987 and 1998. The report identifies dominant contributors to component unreliability and provides an evaluation of significant trends. In addition, this study includes a comparison with air-operated valve unreliability estimates published in probabilistic risk assessments (PRAs) and individual plant examinations (IPEs).
Significant findings from this study are as follows:
* Probability of failure on demand. The AOV probability of failure on demand estimates developed in this report for the PWR and BWR RI systems are consistent with the generic value range from NUREG/CR-4550 (which provided the input to the NUREG-1150 analyses), except the PWR RHR system mean value (5.2E-4) is significantly lower than the NUREG/CR-4550 mean value. The generic and calculated probability values are as follows:

Mr. James Lang Director Electric Power Research Institute 1300 W. T. Harris Blvd Charlotte, NC 28262

==Dear Mr. Lang:==

==SUBJECT:==
REQUEST FOR REVIEW OF RELIABILITY STUDY: NUREG-1715, VOL. X, COMPONENT PERFORMANCE STUDY  AIR-OPERATED VALVES, 1987-1998 (DRAFT)
In accordance with our peer review process, we are offering you the opportunity to review and comment on the draft study NUREG-1715, Vol. X on the reliability of air-operated valves (AOVs) at U.S. commercial pressurized water reactors (PWRs) and boiling-water reactors (BWRs). This study documents an analysis of the performance of safety-related AOVs in the PWR and BWR risk-important (RI) systems.
This study is part of an on-going program of risk-based analysis of reactor operating experience. This effort was undertaken to systematically identify risk significant insights and provide feedback to the regulatory process. This study is also being used in the development of risk-based performance indicators that will be based to a large extent on plant-specific system and equipment performance.
This study provides an estimate of the air-operated valve unreliability based on Engineered Safety Features (ESF) actuations and surveillance test demands between 1987 and 1998. The report identifies dominant contributors to component unreliability and provides an evaluation of significant trends. In addition, this study includes a comparison with air-operated valve unreliability estimates published in probabilistic risk assessments (PRAs) and individual plant examinations (IPEs).
Significant findings from this study are as follows:
* Probability of failure on demand. The AOV probability of failure on demand estimates developed in this report for the PWR and BWR RI systems are consistent with the generic value range from NUREG/CR-4550 (which provided the input to the NUREG-1150 analyses), except the PWR RHR system mean value (5.2E-4) is significantly lower than the NUREG/CR-4550 mean value. The generic and calculated probability values are as follows:

Mr. Gary Vine Sr. Washington Representative Electric Power Research Institute 2000 L St., NW, Suite 805 Washington, DC 20036

==Dear Mr. Vine:==

==SUBJECT:==
REQUEST FOR REVIEW OF RELIABILITY STUDY: NUREG-1715, VOL. X, COMPONENT PERFORMANCE STUDY  AIR-OPERATED VALVES, 1987-1998 (DRAFT)
In accordance with our peer review process, we are offering you the opportunity to review and comment on the draft study NUREG-1715, Vol. X on the reliability of air-operated valves (AOVs) at U.S. commercial pressurized water reactors (PWRs) and boiling-water reactors (BWRs). This study documents an analysis of the performance of safety-related AOVs in the PWR and BWR risk-important (RI) systems.
This study is part of an on-going program of risk-based analysis of reactor operating experience. This effort was undertaken to systematically identify risk significant insights and provide feedback to the regulatory process. This study is also being used in the development of risk-based performance indicators that will be based to a large extent on plant-specific system and equipment performance.
This study provides an estimate of the air-operated valve unreliability based on Engineered Safety Features (ESF) actuations and surveillance test demands between 1987 and 1998. The report identifies dominant contributors to component unreliability and provides an evaluation of significant trends. In addition, this study includes a comparison with air-operated valve unreliability estimates published in probabilistic risk assessments (PRAs) and individual plant examinations (IPEs).
Significant findings from this study are as follows:
* Probability of failure on demand. The AOV probability of failure on demand estimates developed in this report for the PWR and BWR RI systems are consistent with the generic value range from NUREG/CR-4550 (which provided the input to the NUREG-1150 analyses), except the PWR RHR system mean value (5.2E-4) is significantly lower than the NUREG/CR-4550 mean value. The generic and calculated probability values are as follows:

Mr. David A. Lochbaum Union of Concerned Scientists 1616 P Street, NW Suite 310 Washington, DC 20036-1495

==Dear Mr. Lochbaum:==

==SUBJECT:==
REQUEST FOR REVIEW OF RELIABILITY STUDY: NUREG-1715, VOL. X, COMPONENT PERFORMANCE STUDY  AIR-OPERATED VALVES, 1987-1998 (DRAFT)
In accordance with our peer review process, we are offering you the opportunity to review and comment on the draft study NUREG-1715, Vol. X on the reliability of air-operated valves (AOVs) at U.S. commercial pressurized water reactors (PWRs) and boiling-water reactors (BWRs). This study documents an analysis of the performance of safety-related AOVs in the PWR and BWR risk-important (RI) systems.
This study is part of an on-going program of risk-based analysis of reactor operating experience. This effort was undertaken to systematically identify risk significant insights and provide feedback to the regulatory process. This study is also being used in the development of risk-based performance indicators that will be based to a large extent on plant-specific system and equipment performance.
This study provides an estimate of the air-operated valve unreliability based on Engineered Safety Features (ESF) actuations and surveillance test demands between 1987 and 1998. The report identifies dominant contributors to component unreliability and provides an evaluation of significant trends. In addition, this study includes a comparison with air-operated valve unreliability estimates published in probabilistic risk assessments (PRAs) and individual plant examinations (IPEs).
Significant findings from this study are as follows:
* Probability of failure on demand. The AOV probability of failure on demand estimates developed in this report for the PWR and BWR RI systems are consistent with the generic value range from NUREG/CR-4550 (which provided the input to the NUREG-1150 analyses), except the PWR RHR system mean value (5.2E-4) is significantly lower than the NUREG/CR-4550 mean value. The generic and calculated probability values are as follows:

Mr. J. J. Kelly, Manager B&W Owners Group Services Framatome Technologies, Inc.
P.O. Box 10935 Lynchburg, VA 24506-0935

==Dear Mr. Kelly:==

==SUBJECT:==
REQUEST FOR REVIEW OF RELIABILITY STUDY: NUREG-1715, VOL. X, COMPONENT PERFORMANCE STUDY  AIR-OPERATED VALVES, 1987-1998 (DRAFT)
In accordance with our peer review process, we are offering you the opportunity to review and comment on the draft study NUREG-1715, Vol. X on the reliability of air-operated valves (AOVs) at U.S. commercial pressurized water reactors (PWRs) and boiling-water reactors (BWRs). This study documents an analysis of the performance of safety-related AOVs in the PWR and BWR risk-important (RI) systems.
This study is part of an on-going program of risk-based analysis of reactor operating experience. This effort was undertaken to systematically identify risk significant insights and provide feedback to the regulatory process. This study is also being used in the development of risk-based performance indicators that will be based to a large extent on plant-specific system and equipment performance.
This study provides an estimate of the air-operated valve unreliability based on Engineered Safety Features (ESF) actuations and surveillance test demands between 1987 and 1998. The report identifies dominant contributors to component unreliability and provides an evaluation of significant trends. In addition, this study includes a comparison with air-operated valve unreliability estimates published in probabilistic risk assessments (PRAs) and individual plant examinations (IPEs).
Significant findings from this study are as follows:
* Probability of failure on demand. The AOV probability of failure on demand estimates developed in this report for the PWR and BWR RI systems are consistent with the generic value range from NUREG/CR-4550 (which provided the input to the NUREG-1150 analyses), except the PWR RHR system mean value (5.2E-4) is significantly lower than the NUREG/CR-4550 mean value. The generic and calculated probability values are as follows:

Mr. Andrew P. Drake, Project Manager Westinghouse Owners Group Westinghouse Electric Corporation Mail Stop ECE 5-16 P.O. Box 355 Pittsburgh, PA 15230-0355

==Dear Mr. Drake:==

==SUBJECT:==
REQUEST FOR REVIEW OF RELIABILITY STUDY: NUREG-1715, VOL. X, COMPONENT PERFORMANCE STUDY  AIR-OPERATED VALVES, 1987-1998 (DRAFT)
In accordance with our peer review process, we are offering you the opportunity to review and comment on the draft study NUREG-1715, Vol. X on the reliability of air-operated valves (AOVs) at U.S. commercial pressurized water reactors (PWRs) and boiling-water reactors (BWRs). This study documents an analysis of the performance of safety-related AOVs in the PWR and BWR risk-important (RI) systems.
This study is part of an on-going program of risk-based analysis of reactor operating experience. This effort was undertaken to systematically identify risk significant insights and provide feedback to the regulatory process. This study is also being used in the development of risk-based performance indicators that will be based to a large extent on plant-specific system and equipment performance.
This study provides an estimate of the air-operated valve unreliability based on Engineered Safety Features (ESF) actuations and surveillance test demands between 1987 and 1998. The report identifies dominant contributors to component unreliability and provides an evaluation of significant trends. In addition, this study includes a comparison with air-operated valve unreliability estimates published in probabilistic risk assessments (PRAs) and individual plant examinations (IPEs).
Significant findings from this study are as follows:
* Probability of failure on demand. The AOV probability of failure on demand estimates developed in this report for the PWR and BWR RI systems are consistent with the generic value range from NUREG/CR-4550 (which provided the input to the NUREG-1150 analyses), except the PWR RHR system mean value (5.2E-4) is significantly lower than the NUREG/CR-4550 mean value. The generic and calculated probability values are as follows:

Mr. Dennis Townsend General Electric Nuclear Energy Owners Group GE Nuclear Energy 175 Curtner Avenue M/C 187 San Jose, CA 95125

==Dear Mr. Townsend:==

==SUBJECT:==
REQUEST FOR REVIEW OF RELIABILITY STUDY: NUREG-1715, VOL. X, COMPONENT PERFORMANCE STUDY  AIR-OPERATED VALVES, 1987-1998 (DRAFT)
In accordance with our peer review process, we are offering you the opportunity to review and comment on the draft study NUREG-1715, Vol. X on the reliability of air-operated valves (AOVs) at U.S. commercial pressurized water reactors (PWRs) and boiling-water reactors (BWRs). This study documents an analysis of the performance of safety-related AOVs in the PWR and BWR risk-important (RI) systems.
This study is part of an on-going program of risk-based analysis of reactor operating experience. This effort was undertaken to systematically identify risk significant insights and provide feedback to the regulatory process. This study is also being used in the development of risk-based performance indicators that will be based to a large extent on plant-specific system and equipment performance.
This study provides an estimate of the air-operated valve unreliability based on Engineered Safety Features (ESF) actuations and surveillance test demands between 1987 and 1998. The report identifies dominant contributors to component unreliability and provides an evaluation of significant trends. In addition, this study includes a comparison with air-operated valve unreliability estimates published in probabilistic risk assessments (PRAs) and individual plant examinations (IPEs).
Significant findings from this study are as follows:
* Probability of failure on demand. The AOV probability of failure on demand estimates developed in this report for the PWR and BWR RI systems are consistent with the generic value range from NUREG/CR-4550 (which provided the input to the NUREG-1150 analyses), except the PWR RHR system mean value (5.2E-4) is significantly lower than the NUREG/CR-4550 mean value. The generic and calculated probability values are as follows:

ABB Combustion Engineering Owners Group c/o Gordon Bischoff, CEOG Project Manager M.S. 9615-1932 2000 Day Hill Road Windsor, CT 06095

==Dear Mr. Bischoff:==

==SUBJECT:==
REQUEST FOR REVIEW OF RELIABILITY STUDY: NUREG-1715, VOL. X, COMPONENT PERFORMANCE STUDY  AIR-OPERATED VALVES, 1987-1998 (DRAFT)
In accordance with our peer review process, we are offering you the opportunity to review and comment on the draft study NUREG-1715, Vol. X on the reliability of air-operated valves (AOVs) at U.S. commercial pressurized water reactors (PWRs) and boiling-water reactors (BWRs). This study documents an analysis of the performance of safety-related AOVs in the PWR and BWR risk-important (RI) systems.
This study is part of an on-going program of risk-based analysis of reactor operating experience. This effort was undertaken to systematically identify risk significant insights and provide feedback to the regulatory process. This study is also being used in the development of risk-based performance indicators that will be based to a large extent on plant-specific system and equipment performance.
This study provides an estimate of the air-operated valve unreliability based on Engineered Safety Features (ESF) actuations and surveillance test demands between 1987 and 1998. The report identifies dominant contributors to component unreliability and provides an evaluation of significant trends. In addition, this study includes a comparison with air-operated valve unreliability estimates published in probabilistic risk assessments (PRAs) and individual plant examinations (IPEs).
Significant findings from this study are as follows:
* Probability of failure on demand. The AOV probability of failure on demand estimates developed in this report for the PWR and BWR RI systems are consistent with the generic value range from NUREG/CR-4550 (which provided the input to the NUREG-1150 analyses), except the PWR RHR system mean value (5.2E-4) is significantly lower than the NUREG/CR-4550 mean value. The generic and calculated probability values are as follows:

Date    12/12/00 ROUTING AND TRANSMITTAL SLIP TO: (Name, office symbol, room #, building, agency/post)                    Initials       Date
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Action                         File                    Note and Return Approval                       For Clearance           Per Conversation As Requested                   For Correction          Prepare Reply Circulate                      For Your Information    See Me Comment                        Investigate           X Concurrence/Signature Coordination                   Justify REMARKS REQUEST FOR REVIEW OF RELIABILITY STUDY: NUREG-1715, VOL. X, COMPONENT PERFORMANCE STUDY  AIR-OPERATED VALVES, 1987-1998 Room # - Bldg.
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