ML20245A155
| ML20245A155 | |
| Person / Time | |
|---|---|
| Issue date: | 02/09/1987 |
| From: | Harold Denton Office of Nuclear Reactor Regulation |
| To: | Sniezek J NRC OFFICE OF THE EXECUTIVE DIRECTOR FOR OPERATIONS (EDO) |
| Shared Package | |
| ML20245A157 | List: |
| References | |
| REF-GTECI-105, REF-GTECI-NI, TASK-105, TASK-OR NUDOCS 8702180553 | |
| Download: ML20245A155 (6) | |
Text
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MEMORANDUM FOR: James H. Sniezek, Deputy Executive Director for Regional Operations and Generic Requirements
'FROM:
Harold R. Denton, Director Office of Nuclear Reactor Regulation
SUBJECT:
ADDITIONAL INFORMATION REGARDING NRR PROPOSED 10 CFR 50.54f LETTER TO ALL LICENSEES ON PRESSURE ISOLATION VALVES By my memorandum to you dated August 29, 1986 it was proposed to issue a generic letter to all licensees in order to verify compliance with the current licensing basis for each plant regarding maintenance of the leak-tight integrity of pressure isolation valves (PIVs) at the reactor coolant pressure boundary (RCPB). On October 17, 1986, members of the CRGR staff contacted members of the NRR staff and indicated that the General Design Criteria (GDC) as listed in 10 CFR 50, Appendix A may not describe the licensing basis for all licensed plants since some plant licenses predate the GDC, and further, the NRC staff might be making a new interpretation of the GDC. The CRGR staff f
indicated that, at least prior to 1980, neither the NRC staff nor the licensees at the time of the licensing review, interpreted the GDC to require periodic testing to verify individual PIV closure integrity.
The NRC staff's review process has always bm characterized as an audit.
It has never been the staff's position that verification of the position and integrity of valves which are part of the RCPB is not required.. The GDC are quite clear on this issue and the staff has actively been advocating the testing of all PIVs since 1980.
It is therefore not clear that the staff is now making a new interpretation of an existing requirement. However, as requested, NRR has modified the text of the proposed generic letter and provided additional information as outlined in Paragraph II.A. (a), (b) and (c) of the 4
CRGR Charter, Revision 3, dated September 1986.
The requested additional information is as follows:
(a) Problem statement including a description of the need for information in terms of the potential safety benefit:
The purpose of the proposed generic letter is to seek information concerning the methods by which all operating reactor licensees are periodically verifying the integrity of the RCPB by appropriate CONTACT:
- 0. Rothberg, DSR0/EIB 49-28204 i
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.i James H. Sniezek FEB 09 1987 tests or verifications of the leak-tight integrity of all PIVs. A number of precursor events involving PIVs as well as other valves have indicated to the staff that the RCPB may not be protected in all operating circumstances. The protection of the leak-tight integrity of the RCPB is of primary concern in order to avoid overpressurizing an attached low pressure system and possibly causing a LOCA. It is essential that NRC obtain information from licensees in order to confirm our perception that, at least at some plants, closure of these valves is not being periodically monitored to assure that two leak-tight redundant barriers are in place during plant operation. Along with the results of the studies conducted incident to the resolution of Generic Issue # 105, Intersystem-LOCA, the responses are expected to assist NRC with the formally required justification for closure verification of these valves at all licensed plants. Based on the 1"ensee replies, it may be determined that an immediate safety
-neern exists and that short term action is necessary prior to the resolution of Generic _ Issue i
- 105. Any short term actions proposed will be submitted fo CRGR review.
(b) Licensee actions required and the cost to develop a response to the information request:
- 1. List all PIVs in the plant (Range is from 10 to 35, approximately)
- 2. Describe the test pr-formed to verify closure and the test interval for each PIV Costs per reactor are estimated as follows (assuming $40 per man hour):
- a. If all valves are being) tested it is estimated that it will cost about$1600(1 man-week to prepare a letter stating the test method and frequency.
- b. If only Event V valves are being tested or no valves are being tested:
Resources to identify PIVs and existing test procedure, approximately,$3209 l
(c) Anticipated schedule for NRC use of the information:
Issue Generic Letter - 2/87 Receive Replies
- 5/87 Finalize Results along with GI # 105 - 7/87 1.
Provide Proposal to CRGR - 10/87 4
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' James H. Sniez:k-EB 0 9 g In a'ddition, the text of the proposed gene'ric letter has been modified to reflect the preliminary comments of the CRGR staff and is enclosed.
'Drlginal Signed Byi Richard H. Vollmel, Harold R. Denton, Director Office of Nuclear Reactor Regulation
Enclosure:
As stated
- Please see previous concurrence.
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ENCLOSURE TEXT OF PROPOSED GENERIC LETTER TO ALL OPERATING REACTOR LICENSEES Pursuant to 10 CFR 50.54f f), NRC is seeking to verify ycur ccmplianc;. With
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verific;;ica the methods, if any, by which each operating reactor licensee is assuring the Tsak-tight integrity of all pressure isolation valves as independent barriers against abnormal leakage, rapidly propagating failure, and gross rupture of the reactor coolant pressure boundary.
Pressure isolation valves (PIVs) are defined for each interface as any two valves in series within the reactor coolant pressure boundary which separate the high pressure reactor coolant system (RCS) from an attached low pressure system. These valves are normally closed during power operation. The reactor coolant pressure boundary (RCPB) is defined in 10 CFR 50.2 and generally includes all PIVs.
Periodic tests or verifications of the leak tight integrity of all pressure isolation valves are necessary in order to assure the integrity of the RCPB in accordance with 10 CFR 50, Appendices A and B.
General Design Criterion (GDC) 14 of 10 CFR 50, Appendix A requires that "The reactor coolant pressure boundary shall be designed, fabricated, erected, and tested to the highest quality standards practical..." GDC 32 states that " Components which are part of the reactor coolant pressure boundary shall be designed to permit (1) periodic inspection and testing of important areas and features to assess their structural and leak tight integrity..." Further, as outlined in Appendix B to 10 CFR 50, each licensee's quality assurance program must include planned and systematic actions which will provide adequate confidence that these components will perform satisfactorily in service.
All plants licensed since 1979 should have all PIVs listed in the Technical Specifications along with testing intervals, acceptance criteria and limiting conditions for operation. Certain older plants were required to periodically leak test, on an individual basis, only those PIVs which were listed in an Order dated April 20, 1981 (Event V Order). That order was sent to 32 operating PWR's and 2 operating BWR's. Other older plants have had no j
requirements imposed to individually leak test any of their PIVs.
A number of events have occurred in LWRs involving leakage past pressure isolation valves, failures of the valves, inadvertent actuation of the valves, i
or mispositioning of the valves. NRC is therefore seeking assurances that the RCPB is being protected, in accordance with the GDC and Appendix B requirements of 10 CFR 50, as outlined above.
Accordingly, you are requested to submit a list of all pressure isolation valves in your plant. For each valve, describe the test performed to assure
.the integrity of the valve as an independent barrier at the RCPB along with l
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the acceptance criteria for leakage, limiting conditions for operation, and frequency of test performance. For th;;; valve; fcr c'.ich verific; tion of-pre;;;re integrity.nd 10;h tightne;; i; not perfor cd p;riodically ;nd on en-ir.dividuci b;;i;, prcvid; j;;tificatica why you believe y;;r practice
- ti;fic; the requirement; cf the regulation;. This information is required to be submitted within 90 days of this letter.
If current plant Technical Specifications require leak rate testing of all of the PlVs in the plant, your reply to that effect will be sufficient.
Sincerely, Harold R. Denton, Director Office of Nuclear Reactor Regulation i
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Dist'ribution H. Denton R.-Vollmer
'J. Lyons J. Clifford D. Crutchfield G. Lainas f:-
T.-Speis G. Holahan-H. Thompson F. Miraglia.
R. Bernero W. Russell B. Sheron T. Novak
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F. Schroeder W. Houston D.'Zieman
- 0. Rothberg F. Cherny R. Bosnak J. Page R. Kirkwood W. Minners R. Woods W. Millstead Central File DSR0 Chron EIB Reading
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