ML20237H518
| ML20237H518 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 08/20/1987 |
| From: | Mcneill S Office of Nuclear Reactor Regulation |
| To: | Tiernan J BALTIMORE GAS & ELECTRIC CO. |
| References | |
| GL-83-28, NUDOCS 8708250051 | |
| Download: ML20237H518 (4) | |
Text
7 August 20 1987 0
Docket Nos. 50-317 DISTRIBUTION and 50-318
% Docket Filea E. Jordan NRCPDR J. Partlow Local PDR ACRS(10) i PDI-1 Rdg.
C. Vogan S. Varga S. McNeil Mr. J. A. Tiernan B. Boger L. Tripp Vice President-Nuclear Energy OGC Baltimore Gas and Electric Company
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P. 0. Box 1475 i
Baltimore, Maryland 21203
Dear Mr. Tiernan:
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION CONCERNING BG&E RESPONSES TO GENERIC LETTER 83-28 1
The staff has completed its review of your submittal dated February 29, 1984, with respect to your responses to Items 4.2.3 and 4.2.4 of Generic Letter 83-28, " Required Actions Based on Generic Implications of Salem ATWS Events".
The staff has determined that additional information is necessary to facilitate the completion of our review cuncerning the BG&E responses to these items. Our request for additional information is enclosed.
Please respond to this request for additional information within 60 days of your receipt of this letter.
If you are unable to respond within this period, please notify us of your intended schedule within 30 days of receipt of this letter.
This request affects fewer than ten respondents, therefore OMB clearance is not required under PL 96-511.
Please call me if I can be of any assistance is resolving these items.
I Sincerely, I
i Scott Alexander McNeil, Project Manager Project Directorate I-1 Division of feactor Projects, I/II
Enclosure:
1 As stated I
cc:
See next page l
l PDI-1 PDI-1 CVogan SMcNei d M b
8/\\ /87 8/.20/87 8708250051 870820 PDR ADDCK 05000317 P
PDR j
Mr. J. A. Tiernan v
Baltimore Gas & Electric Company Calvert Cliffs Nuclear Power Plant i
cc:
Mr. John M. Gott, President Regional Administrator, Region I Calvert County Board of U.S. Nuclear Regulatory Comission Commissioners Office of Executive Director Prince Frederick, Maryland 20768 for Operations 631 Park Avenue D. A. Brune, Esq.
King of Prussia, Pennsylvania 19406 General Counsel Baltimore Gas and Electric Company P. 0. Box 1475 Baltimore, Maryland 21203 Jay E. Silberg, Esq.
Shaw, Pittman, Potts and Trowbridge 1800 M Street, NW Washington, DC 20036
~j Mr. M. E. Bowman, General Supervisor Technical Services Engineering Calvert Cliffs Nuclear Power Plant i
MD Rts 2 & 4, P. O. Box 1535 Lusby, Maryland 20657-0073 Resident Inspector c/o U.S. Nuclear Regulatory Commission P. O. Box 437 j
Lusby, Maryland 20657-0073 j
Bechtel Power Corporation ATTN: Mr. D. E. Stewart f
Calvert Cliffs Project Engineer 15740 Shady Grove Road Gaithersburg, Maryland 20760 Combustion Engineering, Inc.
ATTN: Mr. W. R. Horlacher, III Project Manager P. O. Box 500 1000 Prospect Hill Road Windsor, Connecticut 06095-0500 1
Department of Natural Resources Energy Administration, Power Plant s
Siting Program ATTN: Mr. T. Magette Tawes State Office Building Annapolis, Maryland 21204 i
o e
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b T
REQUEST FOR ADDITIONAL INFORMATION l
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l CONCERNING ITEMS 4.2.3 AND 4.2.4 0F GENERIC LETTER 83-28 l
i BALTIM0RE GAS & ELECTRIC COMPANY CALVERT CLIFFS NUCLEAR POWER PLANT, UNITS 1 AND 2 j
DOCKET N05. 50-317 AND 50-318 I
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Item 4.2 of Generic Letter 83-28 requires licensees or applicants to describe t
their preventive maintenance and surveillance program for ensuring reliable j
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 l
of the breakers or components consistent with demonstrated life cycles. The
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licensee submitted a response to Item 4.2 (Parts 3&4) by letter dated February l
I 29, 1984.
In that response the licensee stated that as an alternative to con-ducting a life cycle testing program, they are participating in a joint Babcock and Wilcox (B&W) and CE Owner's Group program for evaluating the performance of GE AK-2 trip breakers. Although the staff supports the joint B&W and CE program, and has generally approved it for trending of reactor trip breaker (RTB) para-meters, we find it alone is insufficient for life qualification of the RTBs.
l The B&W Owner's Group (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 i
support the B&WOG conclusion, or to show why the GE RTBs are less susceptible to i
wear than the Westinghouse RTBs.
B&WOG has not conducted cyclic testing of the GE AK RTBs, nor has aging been g
addressed. _Although Westinghouse presented the results of cyclic testing on the 05-416 RTB in WCAP-10835 " Report of the DS-416 Reactor Trip Breaker Under-voltage and Shunt Trip Attachments Life Cycle Tests," it neither addressed l
life qualification of the RTBs nor noncyclic life-limiting or performance-de-grading phenomena (i.e., 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 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 br 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 identified, but is only demonstrated to be adequate.
Ongoing life testing is an acceptable alternative to formal life testing fo?
the purpose of establishing a specific qualified life for RTBs. Ongoing live testing will demonstrate that the qualified life, though not specifically known,
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3 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:
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(I) An estimate of the number of demands between refueling outages l
to which the RTB must respond, and the basis for the esstimate.
(2) A definition of relevant, end-of-life related failures (Note that random failures occurrin l
of the " bathtub curve" [g during the constant hazard rate portion plot of failure rate vs. time] are not relevant to a life test). The licensee should (a) identify the l
possible failure modes, (b) categorize each failure mode as an end-of-life type or not, and (c) present a general methodology (for cate-gorizing future failure modes that may not be included in a).
j (3) The action to be taken upon any failure.
l The staff finds that the licensee has not committed to a life testing program.
I 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 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.
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 t,
For ongoing qualification, the licensee should describe how the ongoing program.
qualification results will be used to establish replacement cycles and times.
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