ML20067D253
| ML20067D253 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 12/07/1982 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20067D249 | List: |
| References | |
| NUDOCS 8212130164 | |
| Download: ML20067D253 (3) | |
Text
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SAFETY EVALUATION AMENDMENT No. 11 TO NPF-10 SAN ONOFRE NUCLEAR GENERATING STATION, UNIT 2 DOCKET NO. S0-361 Introduction Py letter dated Friday, December 3,1982, Southern California Edison Company, i
on behalf of itself the other licensees (San Diego Gas and Electric Company, the City of Anahein and the City of P.tverside), requested a revision to Technical Specification 3/4.3.4, Turbine Overspeed Protection. The proposed revision would nodify the liniting condition for operation to allow steam flow in low pressure steam leads in which an inoperative reheat intercept valve is located (said steam flow not to exceed one hour duration per weekly surviellance period).
Our evaluation of the proposed revision is given below.
1 Evaltation During surveillance, it was determined that reheat intercept valves 2200 0 and 2200 T, to LP cylinders 2 and 3, respectively, were inoperative. The valves cannot be fully closed.
In accordance with Tr.chnical Specf fications, reheat stop valves 2200 R and 2200 S were closed, thereby isolating one steam lead, each, to LP cylinders 2 and 3.
There are two steam leads to eacn of three low pressure cylinders.
In order to conform to Technical Specifications, the hcensees must conduct surveillance on the valves in the unaffected low pressure stean leads; i.e., the valves must be cycled completely (open-close-open) on a weekly hasis.
If this were to be done under present conditions, it would result In tenaination of all stein flow to LP cylinders 2 and 3 for a short period of tine. The turbine manufacturer has stated that terminating steam flow to an LP cylinder could cause serious danage to the turbine rotor.
To avoid this condition, the licensees have requested that the Technical Specifications be revised to allow the affected low pressure steam leads to be reopened during the weekly valve surveillance for a period not to exceed one hour.
The functions of the reheat stop and intercept valves in the low pressure steam leads is to prevent a turbine overspeed with attendant missile generation potential following an electrical load rejection and/or a turbine trip.
The licensees have provided results of calculations by the turbine nanufacturer which show that turbine speed following a load rejection fraa current power levels (approximately 50% reactor power) can be safely controlled using the high pressure valves only.
Therefore, failure of one or more low pressure valves would not result in unacceptable turbine overspeed.
The staff concurs with the licensees regarding turbine overspeed potential following a load rejection from present power levels.
Based on this, the staff aqrees that a waiver of the Technical Specifications as detailed below would not represent an unacceptable risk to the public health and safety.
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Procedures for Weekly Surveillance of Reheat Stop and Intercept Valves:
1 1.
For LP Cylinder No. 3 Cycle valve No. UV 2200 S Open-Closed-Open.
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Cycle valves UV 2200 V and UV 2200 V in the normal sequen a.
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For LP Cylinder No. 2 ig Cycle volve UV 2200 R Open-Closed-Open.
Cycle valve UV 2200 N and UV 2200 P in the nnrnal sequence a.
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For LP Cylinder No. I Cycle valves in both stean leads in the normal sequence.
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No Valve surveillance should be done for one LP cylinder at a time.
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special sequence for LP cylinijers is required.
These procedures will be in effect only until completion of 50% power testino.
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In the event of an additional valve nalfunction, the Technical Specification
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requirenents nust be re-reviewed by the staff.
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The total time that valves UV 2200 R and UV 2200 S will remain open should 7.
not exceed one hour for each weekly sur%eillance.
Environaertal Consideration He have deternined that this anendment does not authorize a change in effluent types or total amount nor an increase in power level and will Having nade this not result in any significant environmental inpact.
determination, we have further concluded that this amendm and pursuant 10 CFR Section 51.5(d)(4), that an environmental impact statement or negative declaration and environnental impact appraisal need not be prepared in connection with the issuance of this amendnent.
Conclusion Based upon our evaluation of the proposed changes to the San Onofre, Technical Specifications, we have concluded that:
does not involve a significant increase in the probability or consequences of accidents previously considered, does not create the p
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. involve a significant decrease in a safety margin, this amendment does not involve a significant safety hazards consideration; (2) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed nanner, and (3) such activities will be con-ducted in compliance with the Comission's regulations and the issuance of this amendnent will not be ininical to the comon defense and security or to the health and safety of,public.
We, therefore, conclude that the proposed changes are acceptable.
Dated:
DEC 7 1982 t
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