ML20247M158
| ML20247M158 | |
| Person / Time | |
|---|---|
| Site: | McGuire, Mcguire  |
| Issue date: | 05/25/1989 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20247M156 | List: |
| References | |
| NUDOCS 8906020380 | |
| Download: ML20247M158 (3) | |
Text
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NUCLEAR REGULATORY COM' MISSION 7,,
j WASHtNGTON, D. C. 20555
......f SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 96 TO FACILITY OPERATING LICENSE NPF-9 AND AMENDMENT NO. 78 TO FACILITY OPERATING LICENSE NPF-17
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DUKE POWER COMPANY-DOCKET NOS. 50-369 AND 50-370 MCGUIRE NUCLEAR STATION, Ut!ITS 1 AND 2
1.0 INTRODUCTION
By letter dated March 16, 1987, as supplemented April 24, 1987, Duke Power
-Company (the licensee).proposci amendmer.ts to the operating licenses for McGuire Nuclear Station, Uniu, I and-2. The proposed amendment request would Jdelete the requirements in the Technical Specifications (TS) for resistance-
. testing of certain fuses whose function is to provide containment penetration conductor overcurrent protection, and would substitute a requirement that a fuse inspection and maintenance program be maintained to ensure that the fproper size and type of fuse is installed, that the fuses show no signs of deterioration, and that the fuse connections are tight and clean.- The list of
. containment penetration conductor overcurrent protective devices (circuit -
breakers and fuses) would be deleted from the TS and the associated testing technique for these circuit breakers would be relocated to the TS Bases.
2.0 EVALUATION
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a.-
Fuse Testing TS 4.8.4.la.3 requires that anong other things, all containment penetration conductor overcurrent protection devices be periodically demonstrated operable by selecting and functionally testing a representative sample (10%) of each type of fuse on a rotating basis. Prior to these amendments, the functional test was specified to consist of a non-destructive resistance measurement test which was intended to demonstrate that the fuse meets its manufacturer's design criteria. Fuses found inoperable during these functional tests were to be replaced prior to resuming operation and additional testing was to be performed.
The license amendnient application addresses the fact that resistance checking of fuses does not provide a meaningful assurance of the fault interrupting capability of the fuse, and that periodic removal of fuses for testing can compromise the integrity of the fuse holder and contact points. Resistance of 3
fuses varies significantly with temperature and would have to be much higher than normal to indicate degradation. The licensee's experience is that variance of resistance with manufacturer's lot and with temperature has resulted in some fuses not meeting requirements and being needlessly removed from service.
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In lieu of resistance testing, the change by these amendments requires a fuse I
inspection and maintenance program in conformance with IEEE Standard 242-1975. The Standard, Reconnended Practice for Protection and Coordination of Industrial and Commercial Power Systems, states:
" Maintenance of fuses is limited by nature of the device to an inspection to ensure that the proper size fuse is installed, that it shows no signs of deterioration, and that the enclosure is clean and the connections are tight. The size and type of fuses j
should comply with those specified by the engineering department." The
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f ailure mode for fuses is "open," so a fuse which degrades to the point of j
failure would still protect the equipment. The " fail-safe" mode ensures that i
a degraded fuse would not result in damage to the enclosure, conductor, penetration assembly, or load during a fault or overload condition.
The fuse inspection and maintenance program imposed by these amendments provides for identification of problems such as arcing in the enclosure, conductor insulation breakdown, bad connections, as well as providitig verification that the correct fuse is installed. This change, thus, provides appropriate fuse maintenance and is acceptable.
b.
Relocation of Tables and Circuit Breaker Testing Method TS Tables 3.8-la for Unit 1 and 3.8-1b for Unit 2 list the containment penetration conductor overcurrent protective devices (circuit breakers and fuses), their trip setpoints or continuous ratings, and the circuit breaker response times.
The license amendment application requested removal of this list from the TS.
The list of these devices would be maintained in a controlled (QA Condition 1) document entitled " Electrical Controls System Description - Electrical Penetration Circuits," which would be referenced in the associated TS Bases 3/4.8.4.
Maintaining the list in a cocument other than the TS would allow the licensee the flexibility to change the list as needed without first obtaining a TS change (i.e., without prior Commission approval subject to 10 CFR 50.59).
The licensee also proposed that the method of testing the lower voltage circuit breakers, as specified within TS 4.8.4.la.2, be relocated to the associated TS Bases. Specifically, TS Bases 3/4.8.4 would be supplemented to note that testing of these circuit breakers consists of injecting a current in excess of the breaker's nominal setpoint and measuring the response time. The measured response time is then compared to the manufacturer's data to ensure that it is less than or equal to a value specified by the manufacturer.
The NRC staff finds that the present McGuire TS is substantially similar to the existing STS for Westinghouse plants, and that the proposed relocation of Tables 3.8-la, and 3.8-1b, and the method of testing the circuit breakers would be inconsistent with the existing STS. The Westinghouse Owners Group has recently proposed a new STS in response to the TS Improvement Program. Under the TS Improvement Program, the NRC recognizes the overcurrent devices TS to be a suitable cardidate for relocation to other controlled documents. However, the proposed changes for McGuire contain differences from the proposed new STS.
Moreover, since review of the new STS is presently in
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. process, and absent any significant safety issue, we conclude that the existing McGuire TS should be retained until the new STS is established and the opportunity is available fer review of the McGuire TS document to the new, approved STS. Accordingly, this portion of the licensee's request is denied.
3.0 ENVIR0ffiENTAL C0t! SIDERATION These amendments involve changes to the installation or use of facility com-ponents located within the restricted area as defined in 10 CFR Part 20 and changes in surveillance requirements. The staff has determined that the amendments involve no significant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite and that there is no significant increase in individual or cumulative occupational exposure. The NRC staff has made a determination that the amendments involve no significant hazards consideration, and there has been no public comment on such finding. Accordingly, the amendments meet the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9). Pursuant to 10 CFR 51.22(b) no environmental impact statement or environmental assessment need be prepared in connection with the issuance of these amendments.
4.0 CONCLUSION
The Commission made a proposed determination that the amendments involve no significant hazards consideration which was published in the Federal Register
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(54 FR 9916) on March 8, 1989. The Commission consulted with the state of l
No public comments were received, and the state of North j
Carolina did not have any coments.
We have concluded, based on.the considerations discussed above, that: (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, and (2) such activities will be conducted in compliance with the Commission's regulations, and the issuance of these amendments will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor:
D. Hood, PD#11-3/DRP-I/II Dated: May 25, 1989 l
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