ML19210B702
| ML19210B702 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 10/02/1979 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML19210B697 | List: |
| References | |
| TAC-08164, TAC-8164, NUDOCS 7911120113 | |
| Download: ML19210B702 (2) | |
Text
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO. 20 TO FACILITY OPERATING LICENSE NO. NPF-3 THE TOLEDO EDISON COMPANY AND THE CLEVELAND ELECTRIC ILLUMINATING COMPANY DAVIS-BESSE NUCLEAR POWER STATION, UNIT NO. 1 DOCKET NO. 50-346 Introduction By letter dated January 13, 1978, the Toledo Edison Company (TECO or the licensee) requested amendment to Facility Operating License No. NPF-3.
The amendment would modify the Technical Specifications for Davis-Besse Nuclear Power Station, Unit No.1 (DB-1), to incorporate surveillance requirements for throttle valves used in the low pressure injection system.
Discussion and Evaluation
.The High and Low Pressure Safety Injection system (HPSI and LPSI) designs of many Pressurized Water Reactors (PWR) utilize a comon low pressure and a comon high pressure header to feed the reveral cold (and in some cases hot) leg injection points. Maintenance of proper flow resistance and pres-sure drop in the piping system to each injaction point is necessary to:
(1) prevent total pump flow from exceeding runout conditions when the system is in its minimum resistance configuration; (2) provide a proper flow split between injection points in accordance with the assumptions us:d in the Emergency Core Cooling System - Loss of Coolant Accident (ECCS-LOCA) analyses; and (3) provide an acceptable level of total ECCS flow to all injection points equal to or above that assumed in the ECCS-LOCA analyses.
On many plants, there are motor operated valve (s) in the lines to each injection point that have stops which are set during preoperational flow testing of the plant to insure that these flow require'ments are satisfied.
On other plants, electrical or mechanical stops on the Safety Injection System's isolation valve (s) are used for this purpose.
DB-1 utilizes mechanical stops to satisfy these ECCS flow requirements.
While preoperational HPSI/LPSI flow testing is utilized tc assure that the valves used to throttle flow have been properly set, we have concladed that periodic surveillance requirements are needed to assure that these settings are maintained throughout the life of the plant.
Consequently, we requested all PWR licensees to propose changes to their Technical Specifications, as appropriate, to incorporate periodic surveillance require-ments for these valves.
Sample surveillance requirements, developed by the NRC staff, were provided to licensees for guidance in developing proposed '
l changes.
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The tample requirements include periodic verification of throttle valve pas. tion stop settings and verification of proper ECCS flow ratcs when-ever system modifications are made that could alter flow characteristics.
The. request for proposed Technical Specification changes was sent to TECO on Noveiber 9, 1977.
TECO responded to our request with respect to DB-1 by submittal dated January 13, 1978.
We discussed the submittal w th the licensee and i
they agreed to modifications which would specify the' parameter of operation curing the flow balance tests. This submittal, as modified, contained proposed changes to the Technical Specifications that are in agreement with our requirements.
Based on our review, we have concluded that TEC0's proposed increased surveillance requirements would provide sufficient additional assurance that proper valve settings for ECCS flow and flow di:tributions will be maintained throughout plant life; and thus, the proposed changes are acceptable.
Environmental Consideration'
.'We have determined that the amendment does not authorize a cnange in effluent types ar total amounts nor an increase ir 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 stand environmental impact, and pursuant to 10 CFR 951.5(d)(4) point of
, that an environmental imoact' statement or negative declaration and environmental impact appraisal need not be prepared in connection with the issuance of the amen 6nent.
Conclusion We have concluded, based on the considerations discussed above, that:
(1) because the amendment does not involve a significant increase in
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the probability or consequences of accidents previously considered and does not involve a significant decrease in a safety margin, the amendment does not involve a significant hazards consideration, (2) there is reasonable 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 w'ith the Commission's regulatiens and the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.
Date: October 2, 1979 i
p 1215 292