ML20235K560
| ML20235K560 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 09/30/1987 |
| From: | De Agazio A Office of Nuclear Reactor Regulation |
| To: | Shelton D TOLEDO EDISON CO. |
| References | |
| D-B-87-010, D-B-87-10, GL-83-28, TAC-53907, NUDOCS 8710050145 | |
| Download: ML20235K560 (5) | |
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1 September 30, 1987 Docket No. 50-346 DISTRIBUTION
-Serial No. D-B 87-010.
4DetetgUe/
TBarnhart(4)
Davis-Besse Nuclear.. Power Station, NRC & Local PDR WJones Unit No. 1
.PD31 Gray File EButcher
- Mr. Donald C. Shelton GHolahan 0GC-Beth Vice. President, Nuclear.
RIngram DHagan Toledo Edison Company Edison Plaza - Stop 712.
ADeAgazio EJordan 300 Madison Avenue
~
JPartlow ACRS(10)
Toledo, Ohio 43652; GPA/PA ARM ARN/LFMB
Dear Mr. Sh'elton:
SUBJECT:
GENERIC-LETTER 83-28, ITEM 4-2 (PARTS 3 AND 4 REQUEST FOR ADDITIONAL.INFORMATION (TAC 53907 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 operation. Parts 3 and 4 of Item 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.
Toledo Edison. Company submitted a response to Item 4.2 (Parts 3&4) by letter dated November 7, 1983 (Serial No. 1000). Our review of this response. finds it to be inadequate as indicated ~in~the enclosed Request For Additional Information. Please provide your response no later than November 30, 1987.
The information requested in this letter affects fewer than ten respondents;
.therefore, ONB clearance is not required under PL 96-511.
Sincerely, Ungin'al signed by
. Albert W. De Agazio, Project Manager Project Directorate 111-1 Division of Reactor Projects - III, IV, V & Special Projects
Enclosure:
As stated cc: w/ enclosure A. Toalston See next page l
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e Mr. Donald C.'Shelton Davis-Besse Nuclear Power Station Toledo _ Edison Company Unit No. 1 CC:
Donald H. Hauser, Esq.
The Cleveland Electric Radiological Health Program Illuminating Company Ohio Department of Health P.~ 0. Box 5000 1224 Kinnear Road
- Cleveland, Ohio 44101 Columbus, Ohio 43212 Mr. Robert W.' Schrauder Attorney General i
Manager, Nuclear Licensing Depe.rtment of Attorney Toledo Edison Company General Edison Plaza 30 East Broad Street 300 Madison Avenue Columbus, Ohio 43215 Toledo, Ohio 43652 Mr. James W. Harris, Director Gerald.Charnoff, Esq.
(Addressee Only)
Shaw,'Pittman, Potts Division of Power Generation and Trowbridge Ohio Department of' Industrial Relations 2300 N Street N.W.
2323 West-5th Avenue Washington, D.C. 20037 P. 0.. Box 825 Columbus, Ohio 43216 Regional Administrator, Region III U.S. Nuclear Regulatory Commission Ohio Environmental Protection Agency 799 Roosevelt Road 361 East Broad Street Glen Ellyn, Illinois Columbus, Ohio 43266-0558 President, Board of Mr. Robert B. Borsum County Commissioners of Babcock & Wilcox Ottawa County l
Nuclear Power Generation Division Port Clinton, Ohio 43452 Suite 200, 7910 Woodmont Avenue Bethesda, Maryland 20814 State of Ohio
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-Public Utilities Commission l
Resident Inspector 180 East Broad Street U.S. Nuclear Regulatory Commission Columbus, Ohio 43266-0573 5503 N. State Route 2 Oak Harbor, Ohio 43449 l'
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REQUEST FOR ADDITIONAL INFORMATION ITEM 4.2 (PARTS 3&4) 0F GENERIC LLITER 83-28 5
DAVIS BESSE NUCLEAR POWER STATION, UNIT 1 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 operation.
Parts 3 and 4 of item 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 November l
7, 1983.
In that response the licensee described the B&W Owners Group (B&WOG)
Reactor Trip Breaker (RTB) Reliability Monitoring Program. Although the staff supports the monitoring program and has generally accepted it for RTB parameter 5
trending, we find that it alone does not adequately address life qualification of the RTB or its components.
B&WOG has concluded that the design of the GE AK RTBs is such that the breaker and its tripping devices are not susceptible to a wear related failure as are the Westinghouse RTBs. No analysis has been presented to support the B&WOG conclusion, or to show why the GE RTBs are less susceptible to wear than the Westinghouse RTBs.
B&WOG has not conducted cyclic testing of the GE AK RTBs, nor has aging been addressed. Although Westinghouse presented the results of cyclic testing on the DS-416 RTB in WCAP-10835 " Report of the DS-416 Reactor Trip Breaker Under-voltage and Shunt Trio Attachments Life Cycle Tests," it neither addressed life qualification of the RTBs nor noneyclic life-limiting.or performance-de-grading phenomena (e.g., aging) for the trip attachments.
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 quelified life of the breaker (for the tripping function) exceeds the expected use projected to the next refueling.
Cycle testirA: by the various owners groups, although it does not consider the 1
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. 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 Monitoring Program.
In this approach, the actual qualified life is not specifically identi-fied, 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. Ongoing life testing will demonstrate that the qualified life, though not specifically known, is longer (in terms of cycles and time) than the integrated service that will be accumulated through the next refueling interval. The description of an ongoing qualification program should include the following:
(1) An estimate of the number of demands between refueling outages to which the RTB must respond, and the basis for the estimate.
(2) A 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. time) 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 not, and (c) present a general methodology for categorizing future failure modes that may not be included in (a).
(3) The action to be taken upon any failure.
The staff finds that the licensee has not comitted to a life testing program.
The licensee should qualify their breakers by (1) actual life testing of the breakers, including aging, on an acceptable sample size or (2) cyclic testing of the breakers, excluding aging, on an acceptable sample size plus an ongoing life testing program.
If the first alternative is selected, the licensee should i
fu l present the results of the ' life testing to the staff-for review.
If the second alternative.is selected, the licensee should present the results of the cyclic testing for staff. review and should describe their ongoing life testing program, including the three items identified above.
If the licensee can demonstrate that the GE AK RTBs are not subject to wear due to cyclic operation the ongoing life testing program would be acceptable without cyclic testing of a sample size.
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The licensee should also present for staff review a replacement program for the breaker and breaker components based on the results of their life qualification program. For ongoing qualification, the licensee should describe how the ongoing
-qualification results will be used to establish replacement cycles and times.
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