ML17319B639
| ML17319B639 | |
| Person / Time | |
|---|---|
| Site: | Cook  |
| Issue date: | 10/15/1982 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML17319B638 | List: |
| References | |
| NUDOCS 8211080278 | |
| Download: ML17319B639 (3) | |
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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION INDIANA AND MICHIGAN ELECTRIC COMPANY DONALD C.
COOK NUCLEAR PLANT UNIT NO.
1
'OCKET NO. 50-315 RELATED TO AMENDMENT NO.
64 TO FACILITY OPERATING LICENSE NO.
DPR-58 Back round By letter dated October 14, 1982, the Indiana and Michigan Electric Company (the licensee) requested a one time extension of the current 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> out-of-service time for one Safety Injection Pump to 10 days.
The Emergency Core Cooling System (ECCS) for the D.
C.
Cook Uni'ts include two centrifugal charging high head
- pumps, two Safety Injection Pumps, and two residual heat removal pumps.
One of the Safety Injection Pumps was found to have excessive vibrations (but within specifications) and was removed from service for adjustments.
The licensee had completed the repairs within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> limit required by the Technical Specifications; however.,
several additional minor adjustments were felt necessary to return the pump to peak performance.
These adjustments will require additional time.
Discussion The D.
C.
Cook Unit 1
ECCS includes low pressure pumps,'afety Injection (SI) pumps
(~1500 psig shut off head) and high head pumps (centrifugal charging pumps).
The plant's'SAR small break LOCA analysis included credit for both the SI pumps and the high head ECCS pumps.
For very small breaks (pressure remaining above 1400 psig) the SI pumps are not called upon.
For larger, small breaks(1200 to 600 psig) both the SI pumps and the high head pumps are used; with approximately 650 gpm from the SI pumps and 550 gpm from the high head pumps.
For large breaks the low head pumps and the accumulators provide the required ECCS flow.
In the event of a small LOCA, resulting in a pressure between 1200 and 600
- psig, and a single failure of the other train of ECCS, there would be only 550 gpm available rather than the 1200 gpm (i.e.,
650 gpm + 550 gpm) assumed in the FSAR analysis.
Evaluation The current operational Safety Injection Pump recently underwent extensive repairs by the licensee and the pump manufacturer.
That pump had been damaged when the recirculation line became blocked and the pump overheated.
The 82ii080278 821015 PDR ADOCK 05000315 P
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licensee now has extensive experience in the pump maintenance and repair and it is believed that the additional repairs being undertaken by the licensee on the pump out of service will benefit that pump's performance.
From a repair standpoint, we agree that the adjustments should be made.
We also agree that the one operating Safety Injection Pump should be reliable based on the extensive repair experience possessed by the licensee.
In discussions with the licensee, they have committed to providing the NRC with a lessons learned document on the repair of the pumps as soon as the document is available.
American Electric Power has provided information from Westinghouse sensitivity studies (performed with the Westinghouse ECCS Small Break, October 1975 Model).
which indicate that reduction in ECCS flow would result in less than a 550'F increase in Peak Clad Temperature (PCT) assuming operation at full power.
The FSAR small break LOCA analysis (performed with a previous ECCS small break model) indicates a
PCT of 1493'F.
The American Electric Power request and discussions with Westinghouse indicate that the calculated peak cladding temperature using the most recently approved Westinghouse ECCS small break model (October 1975) for a 4-loop Westinghouse plant similar to Cook is about 1200'F.
For the purposes of this evaluation and compatibility with the ECCS flow rate sensitivity studies mentioned above we find this reference acceptable.
The resulting net peak cladding temperature (about 1750'F, accounting for the 550'F increase in PCT due to reduced ECCS flow) is below that of the design basis case and thus small breaks continue not to be limiting. Additionally the request is for operation without the SI pump for an extension of 10 days.
~Suamar Based on the information provided by the licensee, we conclude that operation in the proposed manner would not result in exceeding the Commission's regu-lations (10 CFR 50.46) in the event of a LOCA with a single failure.
We, there-fore, find the proposed change acceptable and conclude that it'would not result in an undue risk to the health and safety of the public.
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Environmental Consideration We have determined that the amendment does not authorize a change in effluent types or total amounts nor an increase in power level and will not result in any significant environmental impact.
Having made this determination, we have further concluded that the amendment involves an action which is insignificant from the standpoint of environmental impact and, pursuant to 10 CFR 551.5(d)(4), that an environmental impact statement or negative declaration and environ-mental impact appraisal need not be prepared in connection with the issuance of this amendment.
Conclusion We have concluded, based on the considerations discussed above, that:
(1) because the amendment does not involve a significant increase in the probability or consequences of an accident previously evaluated, does not create the possibility of an accident of a type different from any evaluated previously, and does not involve a significant reduction in a margin of safety, the amendment does not involve a significant hazards consideration, (2) there is'easonable assurance that the health and safety of the public will not be endangered by operation in the proposed
- manner, and (3) such activities will be conducted in compliance with the Commission's regulations and the issuance'of this amendment will not be inimical to the common defense and security or to the health and safety of the public.
Date:
October 15, 1982 Principal Contributors:
F. Orr N. Laubin K. Wichman D. Wigginton