ML17261A588
| ML17261A588 | |
| Person / Time | |
|---|---|
| Site: | Ginna  |
| Issue date: | 08/24/1987 |
| From: | Stahle C Office of Nuclear Reactor Regulation |
| To: | Kober R ROCHESTER GAS & ELECTRIC CORP. |
| References | |
| GL-83-28, TAC-53912, NUDOCS 8708270277 | |
| Download: ML17261A588 (3) | |
Text
d',r Docket No.:
50-244 August 24, 198?
Mr. Roger M. Kober, Vice President Electric and Steam Production Rochester Gas 8 Electric Corporation 89 East Avenue Rochester, New York 14649
Dear Mr. Kober:
SUB)ECT:
REQUEST FOR INFORMATION ON GENERIC LETTER 83-28, ITEM 4.2 (PARTS 3 5 4)
FOR GINNA (TAC NO. 53912)
Enclosed is a request for additional information on Item 4.2 of Generic Letter 83.28 that is related to preventive maintenance and surveillance programs for ensuring reliable reactor trip breaker operation.
Parts 3 and 4 pertains to life testing of an acceptable sample size of the breakers and periodic replacement of the breakers or components consistent with demonstrated life cycl es.
Please respond to this ~equest in 30 days from the receipt of this letter.
Sincerely,
Enclosure:
As stated cc:
See next page Carl Stahle, Project Manager Project Directorate I-3 Division of Reactor Projects I/II DISTRIBUTION:,Docket File, NRC PDR, Local
/87
- NR+uV$4 0 k 0 W
- 08/%
87 ses I
W 0
- 08/Ai'87
~
~
~
~
OFFICIAL RECORD COPY 87082702M 8 00244 P0824 i
@DR gQOCK pDR P
RE VEST FOR ADDITIONAL INFORMATION ITEM R
L R 83-28 R 8 R
G NN NU I
AR P
MER PL NT, U
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 384) by letter dated November 4, 1983.
In that response the licensee referred to the life testing program of the reactor trip breakers (RTBs) being conducted by Westinghouse for the Westinghouse Owners Group.
The licensee stated that the results of the program would be used to substantiate periodic testing requirements and replacement in-tervals for the RTB components.
,Mestinghouse has presented the results of cyclic testing on the D8-50 RTB in MCAP-10852 "Report of the DB-50 Reactor Trip Breaker Shunt and Undervoltage Trip Attachments Life Cycle Tests."
MCAP-10852 addresses only cyclic testing on RTB trip attachments.
It neither addresses life qualification of the RTBs nor non-cyclic life-limiting or performance-degrading phenomena (e.g., aging) for the trip attachments.
Therefore, WCAP-10852 does not constitute an acceptable re-sponse to the concern of the generic letter.
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 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 committed to a life testing program.
The licensee should qualify their breakers by (a) actual life testing of the
- breakers, including aging, on an acceptable sample size or (b) establishing an ongoing life testing program.
If the first alternative is selected, the licensee 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 identified above.
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.