ML20238D000
| ML20238D000 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 09/04/1987 |
| From: | Tam P Office of Nuclear Reactor Regulation |
| To: | Carey J DUQUESNE LIGHT CO. |
| References | |
| GL-83-28, TAC-62955, NUDOCS 8709100491 | |
| Download: ML20238D000 (5) | |
Text
l Docket No. 50-412 September 4, l1987-Y Mr. J. J. 'Carey, Senior Vice President Huclear Group Duquesne Light Company Post Office Box 4 Shippingport, PA 15077
Dear Mr. Carey:
SUBJECT:
BEAVER VALLEY UNIT 2 - SALEM ATWS ITEMS 4.2.3 AND'4.2.4, BREAKER PREVENTATIVE MAINTENANCE (TAC 62955)
By lou er dated March 30, 1984, you responded to the subject items. requested by Gene,ic Letter 83-28. Our review of your. response is ongoing. To complete our review, we would need the information as described in the enclosure.
Please provide your response within 45 days of receipt of this letter.
The reporting and/or recordkeeping requirements contained in this letter-affect fewer than ten respondents; therefore, OMB clearance is not required under P.L.96-511.
Sincerely,.
/S/
Peter S. Tam, Project Manager Pro. ject Directorate I-4 Division of Reactor Projects I/II
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Enclosure:
As stated cc w/ enclosure:
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Mr. J. 0. Carey Duquesne Light Company Beaver Valley. ? Power Station CC:
Gerald Charnoff, Esq.
Mr. Kenneth Grada Manager Jay E. Silberg, Esq.
Safety and Licensing, Shaw, Pittman, Potts & Trowbridge Duquesne Light Company 2300 N Street, N.W.
P. O. Box 4 Washington, DC 20037 Shippingport, Pennsylvania 15077 Mr. C. W. Ewing Quality Assurance Pennsylvania.0ffice of Consumer Manager Advocate Quality Assurance Department ATTN: Michael Bardee Duquesne Light Company 14?E Strawberry Square P. O. Box 186 Harrisburg, Pennsylvania 171?0 Shippingport, Pennsylvania 15077 John D. Burrows, P.E.
Director, Pennsylvania Emergency Director of Utilities Management Agency State of Ohio Room B-151 Public Utilities Commission Transportation & Safety Building 180 East Broad Street Harrisburg, Pennsylvania 17120 Columbus, Ohio '43P66-0573 Mr. T. J. Lex Bureau of Radiation Protection Westinghouse Electric Corporation PA Department of Environmental l
Power Systems Resources P. O. Box 355 ATTN:
R. Janati Pittsburgh, Pennsylvania 15230 P.O. Box 2063 i
Harrisburg, Pennsylvania 17120 i
Mr. P. RaySircar Stone & Webster Engineering Corporation RVPS-2 Records Management Supervisor P. O. Box 2325 Ouquesne Light Company
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Boston, Massachusetts 02107 Post Office Box 4 i
Shippingport, Pennsylvania 15077 U. S. NRC John A. Lee, Esq.
P. O. 181 Duquesne Light Company Shippingport Pennsylvania 15077 1 0xford Centre 301 Grant Street l
Regional Administrator, Region I Pittsburgh, Pennsylvania 15279 j
l U.S. Nuclear Regulatory Commission l
631 Park Avenue King of Prussia, Pennsylvania 19406 l
l l
REQUEST FOR ADDITIONAL INFORMATION ITEM 4.2 (PARTS 354) 0F GEhERIC LETTER 83-28 BEAVER VALLEY POWER STATION, UNIT 2 Item 4.2 of Generic Letter 83-28 requires licensees or applicants to _ describe their preventive maintenance and surveillance program for ensuring reliable reactor trip breaker (RTB) operation.
Parts 3 and 4 of lten 4.2 pertains to life testing of an acceptable sample size of the breakers, and periodic replacement of the breakers or components consistent with demonstrated life cycles.
The licensee submitted a response to Item 4.2 '(Parts 3&4) by letter dated March 30.
1984 In that response the licensee stated that they' wore participating with -
the Westinghouse Owners Group on this issue and would evaluate the recommenda-tions issued following completion of the analyses. The licensee took exception to replacement of RTB components based strictly on life cycles. They stated that items 4.2.3 and 4.2.4 appear to be an extension of the environmental qualification rule, that Paragraph 50.49 (c) states in part that electrical equipment important I
to safety and located in a mild environment is not included under 10 CFR 50.49, and that since the RTBs are safety-related and located in a mild environment they should not be required to be qualified per 10 CFR 50.49 (e).
The staff believes that the licensee's reference only to 50.49 is misplaced, since General Design Criteria 1 of 10 CFR 50, App. A and 10 CFR 50.55a(h) also pertain to the reactor protection systein. The purpose of the life testing is to identify a qualified life for the RTB or any of its replaceable components.
By definition, qualified life is the period of time for which satisfactory performance can be demonstrated for a specific set of service conditions.
Although Westinghouse has presented the results of cyclic testing on the DB-416 RTB in WCAP-10835 " Report of the 05-416 Reactor Trip Breaker Undervoltage and Shunt Trip Attachments Life Cycle Tests," it addresses only cyclic testing on RTB trip attachments.
It neither addresses life qualification of the RTBs nor noneyclic life-limiting or performance-degrading phenomena (e.g., aging) for l
the trip attachments. Therefore, WCAP-10835 does not constitute an acceptable I
retponse to the concern of the genetic letter.
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. If it can be demonstrated that the qualified life of the RTB exceeds the life of the plant, then the specific qualified life need not be identified.
In a-practical sense, the intent of the life testing requirement of the generic letter would be satisfied by demonstrating that the qualified life of the breaker (for the tripping function) exceeds the expected use projected to the next refueling.
Cycle testing by the various owners groups, although it does not consider the effects of aging, may provide evidence to support continued use of the RTBs for one additional refueling cycle, provided that the individual breaker has not shown a sign of degradation based on the licensee's Parametric Trend Mcnitoring
- Program, In this approach, the actual qualified life is not specifically identi-1 fled, but is only demonstrated to be adequate.
Ongoing life testing is an acceptable alternative to formal life testing for the purpose of establishing a specific qualified life for RTBs. -0ngoing life testing j
will demonstrate that the qualified life, though not specifically known, is longer I
(in terms of cycics and time) than the integtated service that will b: accumulated through the next refueling interval. The description of an ongoing qualification i
program should include the following:
(1) estimate of the r. umber of demands between refueling outages to which the RTB must respond, and the basis for the Ostimate.
(2) definition of relevant, end-of-life related failures (Note that random failures occurring during the constant hazard rate portion of the " bathtub curve" (plot of failure rate vs. tiee) are not relevant to a life test).
The licensee should (a) identify the possible failure modes, (b) categorize each failure, mode as an end-of-life type or net, and (c) present a general methodology for categorizing future failure modes that may not be included in(a).
(3) the action to be taken upcn any failure.
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1 The staff finds that the licensee has not committed to a life testing program.
l The licensee should oualify the'ir breakers by (1) actual life testing of the breakers, including aging, on an acceptable sample size or (2) establishing an
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ongoing life testing program.
If the first alternative is selected, the licensee j
should present the results of the life testing to the staff for review.
If the second alternative is selected, the licensee should describe their ongoing life testing program, including the three items listed above.
J The licensee should also present for staff review a replacement program for the l
breaker and breaker components b6 sed on the results of their life qualification program. For ongoing cyclification, the licensee should describe hcw the ongoing l
qualification. resuits will be used to establish replacement cycles and times.
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