NRC Generic Letter 1989-10
KY Ili UNITED STATES
NUCLEAR REGULATORY COMMISSION
OFFICE OF NUCLEAR REACTOR REGULATION
WASHINGTON, D.C. 20555-0001- January 24, 1996 NRC GENERIC LETTER 89-10, SUPPLEMENT 7: CONSIDERATION OF VALVE
MISPOSITIONING IN PRESSURIZED-WATER
REACTORS
Addressees
All holders of operating licenses (except those licenses that have been amended to a possession only status) or construction permits for nuclear power reactors.
Purpose
The U.S. Nuclear Regulatory Commission (NRC) is issuing this generic letter supplement to notify addressees about a revised NRC position regarding consideration of valve mispositioning within the scope of Generic Letter (GL) 89-10 for pressurized-water reactors (PWRs). Although this generic letter supplement forwards a new staff position, no specific action or written response is required.
Background In GL 89-10 (June 28, 1989), Safety-Related Motor-Operated Valve Testing and Surveillance, the staff recommended, among other things, that any motor- operated valve (MOV) in a safety-related system that is not blocked from inadvertent operation from the control room, the motor control center, or the valve itself, be considered capable of being mispositioned (referred to as position-changeable MOVs) and be included in licensee MOV programs. When determining the maximum differential pressure or flow for position-changeable MOVs, the licensees were asked to consider "the fact that the MOV must be able to recover from mispositioning ..." Supplement 1 to GL 89-10 limited the prevention of inadvertent MOV operation within the context of the generic letter to the potential for MOV mispositioning from the control room.
The Boiling Water Reactor Owners Group (BWROG) submitted a backfit appeal on the recommendations for position-changeable valves. The staff, with the assistance of Brookhaven National Laboratory (BNL), reviewed and evaluated the issues concerning the mispositioning of valves from the control room and determined that the recommendations in GL 89-10 should be changed for BWRs.
The BNL study, which used probabilistic risk assessment (PRA) techniques and the NRC staff evaluation and conclusions were transmitted in a letter from the
GL 89-10, Supp. 7 January 24, 1996 NRC to the BWROG dated February 12, 1992. The conclusions were communicated to industry and the public at large via Supplement 4 to GL 89-10, also dated February 12, 1992. Supplement 4 indicated that the NRC would perform a similar review for PWRs and stated that GL 89-10 might be revised, if warranted, to clarify the NRC position regarding consideration of MOV
mispositioning within the scope of GL 89-10 for PWRs.
Description of Circumstances
By letter dated July 21, 1992, the Westinghouse Owners Group (WOG) asked the NRC staff to notify PWR licensees that the provisions of GL 89-10 for valve mispositioning are not applicable to PWRs, based on arguments similar to those made by the BWROG.
Discussion Under contract to the NRC staff, BNL performed a study similar to the one performed for BWRs of the safety significance of inadvertent operation of MOVs in safety-related piping systems of three PWRs. Consistent with Supplement 1 to GL 89-10, the scope of the study was limited to MOVs in safety-related systems that could be mispositioned from the control room. However, because the available PRA models do not include active mispositioning of MOVs or the physical phenomena that could inhibit repositioning, BNL's study of available plant models was limited in its ability to address this issue. Given this limited scope, BNL concluded that the risk insights from the mispositioning of unlocked MOVs were similar for both PWRs and BWRs. Although PWRs tend to have a higher core damage frequency (CDF) than BWRs, which would suggest that the net increase in CDF from mispositioning of MOVs would be higher for PWRs than for BWRs, PWRs typically have a lower conditional containment failure probability, which would tend to balance the overall risk to the public.
The NRC is removing the recommendation that MOV mispositioning be considered by PWR licensees in responding to GL 89-10, as was done for BWR licensees in Supplement 4, in light of the following:
- Corrective actions have been taken by licensees subsequent to the Davis-Besse event (i.e., detailed control room design reviews, independent valve position verification programs, and operator training improvements),
- Corrective actions are being applied to many of the most important valves under the other provisions of GL 89-10,
- Other operational events are absent (other than Davis-Besse) in which mispositioning MOVs from the control room actually set up conditions that prevented repositioning, and
Implementation of this relaxation by licensees is voluntary.
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GL 89-10, Supp. 7 January 24, 1996 Staff Position The staff no longer considers the inadvertent operation of MOVs from the control room to be within the scope of GL 89-10 for PWRs. However, the staff believes that consideration of valve mispositioning benefits safety.
Licensees that have already taken action or made commitments related to valve mispositioning may take advantage of this relaxed staff position provided the licensees document this change in their GL 89-10 programs.
Modifying the provisions in GL 89-10 for valve mispositioning does not affect the GL 89-10 recommendations for licensees to review safety analyses, emergency procedures, and other plant documentation to determine the design- basis' fluid conditions under which all MOVs in safety-related piping systems may be called upon to function. This position also does not supersede the NRC
generic recommendations or regulations on valve mispositioning that pertain to such other issues as interfacing-systems loss-of-coolant accidents (ISLOCAs)
or fire protection (10 CFR Part 50, Appendix R).
Backfit Discussion
This letter represents a relaxation of recommendations set forth in GL 89-10
and prior supplements. Implementation of this relaxation is voluntary and this generic letter supplement requests neither actions nor information from licensees. Therefore, this generic letter supplement is not considered a backfit and the staff has not performed a backfit analysis.
Federal Register Notification
The proposed generic letter supplement was published in the Federal Register for a 30-day public comment period on July 26, 1995. Four comments were received (from Nuclear Energy Institute, Florida Power Corporation, Centerior Energy, and Virginia Power). All four comments supported issuance of the generic letter supplement as written. Centerior Energy also suggested that the supplement clarify how licensees should administratively handle any commitments they might have made related to valve mispositioning. This comment was accepted and is incorporated in the staff position section of this supplement.
'Design-basis conditions are those conditions during both normal operation and abnormal events that are within the design basis of the plant.
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GL 89-10, Supp. 7 January 24, 1996 This generic letter requires no specific action or written response. If you have any questions about this matter, please contact the technical contact listed below or the appropriate Office of Nuclear Reactor Regulation (NRR)
project manager.
e
. trut Director Division of Reactor Program Management Office of Nuclear Reactor Regulation Technical contact: David C. Fischer, NRR
(301) 415-2728 Internet:dcf@nrc.gov Lead project manager: Allen G. Hansen, NRR
(301) 415-1390
Internet:agh@nrc.gov Attachment:
List of Recently Issued NRC Generic Letters
K) K)j Attachment GL 89-10, SUPP. 7 January 24, 1996 LIST OF RECENTLY ISSUED GENERIC LETTERS
Generic Date of Letter Subject Issuance Issued To
96-01 TESTING OF SAFETY-RELATED 01/10/96 ALL HOLDERS OF OLs OR
95-10 RELOCATION OF SELECTED 12/15/95 ALL HOLDERS OF OLs OR
TECHNICAL SPECIFICATIONS CPs FOR NPRs REQUIREMENTS RELATED TO
INSTRUMENTATION
95-09 MONITORING AND TRAINING OF 11/03/95 ALL U.S. NRC LICENSEES
SHIPPERS AND CARRIERS OF
RADIOACTIVE MATERIALS
95-08 10 CFR 50.54(p) PROCESS FOR 10/31/95 ALL HOLDERS OF OLs &
CHANGES TO SECURITY PLANS CPs FOR NPRs WITHOUT PRIOR NRC APPROVAL
88-20, INDIVIDUAL PLANT EXAMINATION 09/08/95 ALL HOLDERS OF OLs Supp. 5 OF EXTERNAL EVENTS FOR SEVERE (EXCEPT THOSE LICENSES
ACCIDENT VULNERABILITIES THAT HAVE BEEN AMENDED
TO POSSESSION-ONLY
95-07 PRESSURE LOCKING AND THERMAL 08/17/95 ALL HOLDERS OF OLs BINDING OF SAFETY-RELATED (EXCEPT THOSE LICENSES
POWER-OPERATED GATE VALVES THAT HAVE BEEN AMENDED
TO POSSESSION-ONLY
OL = OPERATING LICENSE
CP = CONSTRUCTION PERMIT
NPR = NUCLEAR POWER REACTORS
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NUCLEAR ENERGY INSTITUTE .1 _1 Thomas E. Tipton g {xA;,
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August 21, 1995 Chief, Rules Review and Directives Branch U.S. Nuclear Regulatory Commission Washington DC 20555 ATTENTION: Docketing and Service Branch SUBJECT: Proposed for Generic Letter, (GL), 89-10, Supplement 7, Valve Mispositioning in Pressurized-Water Reactors The purpose of this letter is to provide industry's comments on NRC's proposed published generic letter supplement relating to motor operate valve mispositioning in the FederalRegister (60 Fed. Reg. 38378), dated July 26, 1995.
7, The Nuclear Energy Institute (NEI) supports the NRC staff action in Supplement by Generic Letter 89-10 to remove the requirement to address mispositioning pressurized water reactors in responding to GL 89-10. Considering the longevity associated with this particular issue and to preclude further resources spent addressing mispositioning, we encourage an expedited effort in issuing this supplement in final form.
Sincerely, Thomas E. Tipton TET/RCC/ead
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Florida Power CORPORATION
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August 21, 1995 NL95-0077 U. S. Nuclear Regulatory Commission Attn: Chief, Rules Review and Directives Branch Washington, DC 20555 Subject: Comments on the Proposed Generic Communication Generic Letter 89-10,
Supplement 7, Valve Mispositioning in Pressurized-Water Reactors Reference: FR Doc. 95-18320, Filed 7-25-95 Dear Sir:
Supplement 7 to Generic Letter (GL) 89-10 proposes to remove the recommendation to address mispositioning of motor operated valves (MOV) within GL 89-10
responses. Florida Power Corporation strongly endorses this supplement.
Sincerely, LLW iz Kenneth R. Wilson, Manager Nuclear Licensing CRYSTAL RIVER ENERGY COMPLEX: 15760 W Power line St . Crystal River, Florida 34428-6708 a (904) 7956486 A Florida Progress Company jJS' -zxu'-o
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CENTERIOR
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sJohn P Sft.Sft Vic Pw nt-Iucea an
300 Madison Avenue mvPsBssetNur Toledo. OH 43652-01
419-249-2300
Docket Number 50-346 License Number NPF-3 Serial Number 2317 August 23, 1995 United States Nuclear Regulatory Commission Document Control Desk Washington, D. C. 20555 Attention: Chief, Rules Review and Directives Branch Generic Letter 89-10,
Subject: Comments on Proposed Generic Communication, Water Reactors Supplement 7, Valve Mispositioning in Pressurized
(60FR38378,-July 26, 1995)
Gentlemen:
Energy, is partial owner Toledo Edison (TE), a subsidiary of Centerior Nuclear Power of the Davis-Besse of and is responsible for operation for power operation Station (DBNPS). Toledo Edison has been authorized Part 50 licensee, TE has a of the DBNPS since April 1977. As a 10 CFR Regulatory Commission (NRC)
vested interest in any policies the Nuclear operation of a commercial may adopt which can affect the management and the subject Federal nuclear power plant. Toledo Edison has reviewed comments for consideration.
Register notice and submits the following position in the proposed Toledo Edison supports the revised NRC Staff relaxing the staff Generic Letter (GL) 89-10 supplement. However, of the test programs position at this time, i.e., near the conclusion licensees with a minor developed as a result of GL 89-10, does present administrative issue.
commitments or Many affected licensees presently have docketed explicitly statements made by the NRC in docketed correspondence considered in the was stating or implying that "valve mispositioning" program. These (MOV) test development of their Motor Operated Valve licensees may choose to take advantage of the relaxed staff position in GL supplement does not GL 89-10, Supplement 7. Although the proposed PDR ADOCK 05000346 P PDR
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Docket Number 50-346 License Number NPF-3 Serial Number 2317 Page 2 require any response, it is our interpretation that any licensee wishing to take advantage of the relaxation in the staff position would have to docket a letter to the NRC stating such in order to avoid any future misunderstandings pertaining to a licensee's commitments on this subject.
To avoid this situation, TE suggests that the GL supplement, if issued, provide a mechanism by which licensees can take advantage of the position promulgated in the GL supplement. One of the following options should be considered.
1. Provide a statement in the GL supplement allowing licensees to take advantage of the staff position without notifying the NRC, or
2. Provide a statement in the GL supplement stating that licensees who wish to take advantage of the staff position must provide a response to the GL supplement stating their intentions.
Should you have any questions or require additional information, please contact Mr. William T. O'Connor, Manager - Regulatory Affairs, at (419) 249-2366.
Very truly yours, NKP/eld cc: L. L. Gundrum, NRC Project Manager H. J. Miller, Regional Administrator, NRC Region III
S. Stasek, DB-1 NRC Senior Resident Inspector Utility Radiological Safety Board
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7lirL-Zwo! q- August 29, 1995 VIRGINIA POWER
Chief, Rules Review and Directives Branch U.S. Nuclear Regulatory Commission Serial No. GL 95-048 Washington, DC 20555 NL&P/MAE R1 Dear Sir:
PROPOSED GENERIC LETTER 89-10. SUPPLEMENT 7 VALVE MISPOSITIONING IN PRESSURIZED WATER REACTORS
In the July 26, 1995 Federal Register, the NRC announced that it is proposing to issue Generic Letter 89-10, Supplement 7. This proposed generic letter supplement removes the recommendation that MOV mispositioning be considered by pressurized water reactor licensees in responding to Generic Letter 89-10. This recommendation was removed for boiling-water reactor licensees in Supplement 4.
Virginia Power has reviewed the proposed generic letter supplement and supports the proposed action. Virginia Power encourages the NRC's efforts to solicit industry advice and recommendations in developing this proposed generic letter supplement. We also endorse the comments submitted by the Nuclear Energy Institute in their letter dated August 21, 1995.
If you have any questions, please contact us.
Very truly yours, M. L. Bowling, Manager Nuclear Licensing and Programs cc: Mr. Clive Calloway Nuclear Energy Institute
1776 1 Street, Suite 400
Washington, DC 20006-3708
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POLICY ISSUE
(Information)
SECY-96-004 January 3, 1996 FOR: The Commissioners FROM: James M. Taylor Executive Director for Operations SUBJECT: PROPOSED NRC GENERIC LETTER 89-10, SUPPLEMENT 7, "CONSIDERATION
OF VALVE MISPOSITIONING IN PRESSURIZED-WATER REACTORS"
PURPOSE
in the December 20,
To inform the Commission, in accordance with the guidance regarding SECY-91-
1991, memorandum from Samuel J. Chilk to James M. Taylor the staff's intent to issue
172, "Regulatory Impact Survey Report - Final," of letter supplement will the subject generic letter supplement. This generic (PWR) licensees remove the recommendation that pressurized-water reactor responding to Generic consider motor-operated valve (MOV) mispositioning in Testing and Valve Letter (GL) 89-10, "Safety-Related Motor-Operated supplement is attached.
Surveillance." A copy of the proposed generic letter DISCUSSION:
and construction permit In GL 89-10, the staff requested that licensees for testing, inspection, and holders develop a program that "should provide the necessary assurance maintenance of [safety-related] MOVs so as to provide conditions..." by that they will function when subjected to the design-basis December 28, 1989 June 28, 1994, or by three refueling outages following (in part):
(whichever was later). The recommended actions stated
CONTACT
- David C. Fischer NOTE: TO BE MADE PUBLICLY AVAILABLE IN 5
415-2728 WORKING DAYS FROM THE DATE OF THIS PAPER
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The Commissioners -2- is not blocked from inadvertent Any MOV in a safety-related system that the motor control center, or the operation from either the control room, of being mispositioned valve itself should be considered capable and should be included in the (referred to as position-changeable MOVs)
differential pressure or flow for program. When determining the maximum the MOV must be able to recover position-changeable MOVs, the fact that from mispositioning should be considered.
of inadvertent MOV operation Supplement 1 to GL 89-10 limited the prevention to the potential for MOV
within the context of the generic letter Supplement 4 to GL 89-10, which was mispositioning from the control room. for boiling-water reactor (BWR)
issued on February 12, 1992, withdrew in safety-related systems that are not licensees the recommendation that MOVs the control room be considered capable blocked from inadvertent operation from adequacy of the MOV and plant design.
of being mispositioned in assessing the withdraw this recommendation for PWR
Proposed Supplement 7 to GL 89-10 will licensees.
issue should be removed The staff's conclusion that the MOV mispositioning based on the following considerations.
from the scope of GL 89-10 for PWRs is importance of valve mispositioning may First, the staff now concludes that the of other actions to improve the have been overstated, especially in light reduce the likelihood of valve capability of valves to function and to issue is beyond the design- mispositioning. Second, the valve mispositioning it involves the assumption of basis requirements for the plants because will be consistent with the judgments multiple failures. Third, this action the recommendation for BWRs.
made in GL 89-10, Supplement 4, to remove Laboratory and the staff have Fourth, efforts to date by Brookhaven National the risks associated with valve shown that a quantitative assessment of beyond the state-of-the-art for mispositioning is very difficult and largely However, qualitative insight from the current probabilistic risk assessments. valve mispositioning is of limited review of several studies suggests that addressed by focusing on the physical safety significance and that it is best to failure when mispositioned.
phenomena that make some valves vulnerable technical basis for concluding that Since its studies do not provide a strong in "a substantial increase in the retaining the recommendation would resultand safety," (10 CFR 50.109(a)(3)) the overall protection of the public health is to inform PWR licensees that staff concludes that the appropriate action their MOV program unless they address MOV mispositioning need not be a part of it voluntarily.
on the proposed generic letter A notice of opportunity for public comment Register for a 30-day public comment supplement was published in the Federal were received (from Nuclear Energy period on July 26, 1995. Four commentsCenterior Energy, and Virginia Power).
Institute, Florida Power Corporation, the generic letter supplement as All four comments supported issuance of that the supplement clarify how written. Centerior Energy also suggested any commitments they might have made licensees should administratively handle comment was accepted and is related to valve mispositioning. This of the supplement (that is, incorporated in the staff position section
r The Commissioners -3-
"Licensees that have already taken action or made commitments related to valve mispositioning may take advantage of this relaxed staff position provided the licensees document this change in their Generic Letter 89-10 programs.").
Copies of the comments received are available in the NRC Public Document Room (PDR). A copy of the staff evaluation of these comments is available in the NRC central files and will be made available in the PDR after the generic letter supplement is issued.
The proposed generic letter supplement was reviewed by the Committee To Review Generic Requirements (CRGR) during its meeting number 257 on May 10, 1994, and again at meeting number 276 on July 14, 1995. The staff incorporated all comments provided by the CRGR in those meetings. As previously stated, the proposed generic letter supplement was subsequently issued for public comment on July 26, 1995. In light of the public comments on the proposed supplement and because the supplement had not changed substantively since the CRGR's earlier review, on December 18, 1995, the CRGR staff indicated that NRR could proceed with issuance of the generic letter supplement without further interactions with CRGR.
The Office of the General Counsel reviewed this generic letter supplement and has no legal objections to its issuance.
The staff intends to issue this generic letter supplement approximately 10
working days after the date of this information paper.
xecutive Director for Operations Attachment: Proposed Generic Letter 89-10, Supplement 7, "Consideration of Valve Mispositioning in Pressurized-Water Reactors"
DISTRIBUTION:
Commissioners OGC
OCAA
SECY