ML20006F574
| ML20006F574 | |
| Person / Time | |
|---|---|
| Issue date: | 11/14/1989 |
| From: | Advisory Committee on Reactor Safeguards |
| To: | Advisory Committee on Reactor Safeguards |
| References | |
| ACRS-2670, GL-89-10, NUDOCS 9002280188 | |
| Download: ML20006F574 (6) | |
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Me CERTIFIED COPY DATE ISSUED: Novsabar'14,-1989
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SUMMARY
/ MINUTES OF THE ACRS SUBCOMMI1 TEE ON MECHANICAL COMPONENTS OCTOBER 3, 1989 EETHESDA, MARYLAND The ACRS Subcommittee on Mechanical Components met with the NRC Staff on October 3, 1909, at Bethesda, Maryland to 1) discuss C. Michelson's concern on Generic Letter 69-10, 2) be briefed on the recent MOV fail-ures to close against velocity flow, 3) hear status report on action plan on check valves, 4) review the implementation plan on MOV operabil-ity, 5) hear the implementation plan on MOV operability, S) hear an overview on Generic Letter 89-04 concerning in-service testing of pumps-eno valves, and 6) review the preliminary test results on MOV's being-performed-in FRG.
Notice of the meeting was published in the Federal Register on September 19, 1989.- The schedule of items covered in the meeting and a list of handouts are kept with the office copy. There were no written or oral q
g, statements received or presented from members of the public at the meeting.
E. G. Igne was Cognizant ACRS Staff Member for the meeting.
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Principal Attendees ACRS NRC Others co
).M C. Michelson, Chairman F. Cherny C. Callaway,_NUMARC cf C. Wy'ie, Member
- 0. Rothberg W. Pierce, Consultant j$ @
J. Carroll, Member R. Kissel E. Hale, Bechtel cc C. Siess, Member T. Scarbrough R. Fell, NUS g$.
I. Catton, Member R. Baer P. Wohld,'ACRS Consultant E. Brown D. Persinko
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DESIGNATED ORIGINAL O ze R
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Minutes / Mechanical Components Meeting 2
,::.t October 3, 1989 Highlights 1.
O. Rethberg, RES, discussed C. Michelsun's concern regarding design basis requirerents defined in Generic letter 89-10.
He stated that design basis is defined in the regulations, FSAR, Commission orders, and post licensing commitments. Deficiencies in the design basis scenarios are not within the scope of Generic Lette.r 89-10.
He further stated that there does not appear to be a clear regulatory guidance regarding ceficiencies in the design basis itself, absent any ever,t or plant physical ccndition which would mandate a 10 CFR 50.72 or 50.73 response.
Further, he stated that the generic letter was written to recommend'that i
licensees investigate the response of MOV's of the currently applicable oesig basis scenarios. The letter does not recommend any changes to those events and conditions, and therefore adjustment of MOVs would be in accordance with the parameters identified from the study of the existing design b6 sis events and conditions.
4 The subcommittee felt that this is not adequate in light of recent on-going MOV tests, and suggested that ACRS comments on this matter may be necessary.
2.
T. Scarbrough, NRR, discussed MOV failures to close against differ-ential pressure in nuclear power plants. Catawba and Millstone concerns in<this area have been raised by on-going research and plant operating experience.
For example, preliminary results of NRC research reveal that the thrust required to close a valve under full flow con-ditions may be much larger than anticipated. Among the possible
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Ninutes/ Mechanical Components Meeting 3
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contributors, individually or in conibination, to the MOV failures to close are valve'oesign, stem thrust analysis, and. switch settings.
One-particular area of' concern is that valve friction factors supplied by the tranufacturer h6ve been fcund to differ significantly from licens-ee-determined valves.
NRR recently sent a letter to NUMARC requesting that'EPRI perform research addressing design and qualification of MOVs.
The NRC staff alsci informed licensees attending the workshop =on Generic Letter 89-10 that application of test data from prototype must be justified even if the POV is assun.ec to be identical.
T. Scarbrough, next discussed the proposed action plan for MOVs.
NRC activities in this crea are on-going in NRR, RES and AEOD. Other activities are by EPRI, INPO, NUMARC and ASME.
These activities include plant visits, guidelines for implementation of Generic Letter.89-10, signature tracing technique improvements, MOV design improvements, IEEE' maintenance practices and codes on inspecting and qualification of i
MOV's..
.nese efforts should eventually lead to rules ano regulatory guidance for a more reliable MOV.
Beseo on the San Onofre event, the NRC staff issued a staff requirements B
memorandum on February 1986, requiring performance of generic analysis of check valve failures. NRR, RES and AEOD are actively involved in this activity. Generic Issue 105, Interfacing Systems LOCA at LWRs is the primary mechanism leading to resolution of this matter.
INPO, EPRI and ASME are also involved. The effort for the resolution on check 1
valve operability and qualification program is now quite similar to the M0V concern.
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_ Minutes /fiechanical Components i1ceting 4
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R.' Woods, 11RR, reported in some preliminary results of testing performed in the FRG. The first of a second series of blowdown tests on i
flexible wedge isolation valves in a high flow velocity, hot water environment was recently completed. This accident environment is j
typical of that which can be expected to occur should a RWCU pipe 1
develcp a guillotine break outside a BWR containment. The tests are intended to provide important-technical information on valve closure thrust requirements, motor operator diagnostic equipment measurements ar.d capabilities related to Generic issue 87, " Failure of the HPCI Steam Line Without Isolation." Preliminary results and observations from the first test indicated that the disc travel was within 0.5 inches of complete closure at operator trip. Therefore, the valve failed to 4
completely isolate cil fMw. The thrust plot indicates that the disc and guides r:ay base experienced damage during closure. These results are similar tc those obtained at Wylie Laboratory.
Tests perforred on a more flexible-valve (with increase disc gate gap) under similar test ccnditions were successful -- closed fully when operator tripped. This test was repeated three times -- all fully closing and isolating flow.
4.
T. Sullivan, NRR, presented a brief overview on Generic Letter 89-04, " Guidance on Developing Acceptable In-service Testing Programs."
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C. Michelson stated that this generic letter was not reviewed by the ACRS and asked the subcommittee if we should comment on it after the presentation was heard.
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,1 Minutes /l'echanical. Components Meeting 5' October 3, 1989 i
The purposes of the generic letter are to provide generic. guidance on significantin-servicetesting(IST) areas,provideguidanceondevelop-
' ing acceptable IST programs, and clarify approval' status of IST pro-grams.
He stated that no written technical guidance on IST programs existed and huge volumes of programs, revisions, and relief requests from tbc industry were innudating the branch.
Further, relief requests
.1 were unreviewed and implemented without prior NRC approval which is contrary tc Tech. Spec. 4.0.5.
Inspection effectiveness was also 2
hampered.
I IST problem areas exist in code interpretations, Technical Specifications interpretations, and approved alternatives to code requiremen ts.
Workshops on Generic Letter 89-04 were held in the regions in June 1989.
Minutes of the workshops were sent to CRGR for consideration on l
September 6, 1909.
The subcormittee requested a copy of the minutes and the. staff will provide us with a copy.
CRGR will be briefed on this J
matter on October 11, 1989.
Subcommittee Action After deliberations, the subcommittee decided not to comment on Generic Letter 89-04, and will comment on Generic Letter 89-10. A subcommittee report without NRC staff participation will be made to the full ACRS at the October 1989 meeting.
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- w' NOTE:
-A transcript of the meeting is available at the NRC Public-Pocument. Room, 'Gelman Bldg. 2120 "L" Street,- NW.', Washington, ut O.C.; Telephone (202)634-3383 or can be purchased from
' Heritage Reporting Corporation,1220 "L" Street, NW.,
Washington,.D.C. 20005, Telephone (202) 626-4888, e
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