ML17328A341
| ML17328A341 | |
| Person / Time | |
|---|---|
| Site: | Cook  |
| Issue date: | 06/28/1990 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML17328A340 | List: |
| References | |
| NUDOCS 9007260115 | |
| Download: ML17328A341 (2) | |
Text
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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT N0.140 TO FACILITY OPERATING LICENSE NO.
DPR 58 AND AMENDMENT N0.127 TO FACILITY OPERATING LICENSE NO.
DPR-74 INDIANA MICHIGAN POWER COMPANY DONALD C ~
COOK NUCLEAR PLANT UNIT NOS.
1 AND 2 DOCKET NOS.
50"315 AND 50"316
- 1. 0 INTRODUCTION By letter dated January 27,
C.
Cook Units 1 and 2 Technical Specifications (TS).
In the D.
C.
Cook design, the reactor coolant pump (RCP) breaker position provides an anticipatory reactor trip for low flow in one loop in a one out of four trip logic.
The proposed modification changes the one out of four above P-8 (permis'sive above 35K reactor power) to a two out of four logic for all power levels above the P-7 set point (permissive above lOX reactor power).
This logic change is to avoid spurious reactor trip on false signal from a single RCP breaker auxiliary contact.
On staff's request, IMPC provided additional information in a letter dated December 21, 1988, which included review of the change and evaluation of staff's concerns by Westinghouse.
- 2. 0 EVALUATION The Westinghouse standard design of the reactor protection system (RPS) includes anticipatory reactor trips for RCP power supply underfrequency, undervoltage, and the RCP circuit breaker open position.
These anticipatory reactor trips are provided for impending loss of reactor coolant flow and intended to enhance the overall reliability of the RPS.
The low flow reactor trip is the design protection provided by three redundant channels for each loop.
Above P-8, the loss of flow in any loop, as sensed by two out of three-channels, actuates a
The proposed deletion of reactor trip for one out of four RCP breaker open logic above P-8, only removes one of the three anticipatory trips in any loop.
The remaining two anticipatory trips (undervoltage and underfrequency) will adequately provide the required protection before the low flow trip is actuated in any one of the loops.
Additionally, no credit is taken for the reactor trips on a single RCP breaker position above P-8 in any accident analysis for D.
C.
Cook Units 1 and 2.
The proposed change will incorporate a two out of four RCP breaker open logic as an anticipatory reactor trip.
This modification is provided as a standard feature or as a retrofit option for all Westinghouse PWR units.
The change will remove this potential source of spurious trip due to a single failure and 9007260ii8 900628 PDR ADOCK 0S'0009";
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<<2 provide a reduction in undue challenges to the RPS.
The proposed modification affects only" the coincident logic of RPS and does not degrade either its performance or conformance to system functional requirements.
The staff agrees with the Westinghouse conclusion that the diversity and redundancy of RPS will be maintained for the single loop loss of flow event.
'i The proposed changes to the Technical Specifications correctly reflect the coincident logic change and the bases section of the proposed changes provides an acceptable basis for the new logic and functional requirements.
Based on the above evaluation, the staff concludes that the proposed modification of RCP breaker position trip logic in RPS is acceptable.
Additionally, the proposed changes to the Technical Specifications do not involve an unreviewed safety question and are also acceptable.
3.0 EHVIRONViEHTAL CONSIDERATION These amendments involve changes in a requirement with respect to the installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 and a change in a surveillance requirement.
We have 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 radiation exposure.
The Commission has previously issued a proposed finding that these amendments involve no significant hazards consideration and there has been no public comment on such finding.
Accordingly, these 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
We have concluded, based on the considerations discussed above, that (I) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed
- manner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendments wi 11 not be inimical to the common defense and security or to the health and safety of the public.
Date:
June-28, 1990 Principal Contributor:
I. Ahmed, NRR/SICB