ML20051R546
| ML20051R546 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 04/30/1982 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20051R523 | List: |
| References | |
| NUDOCS 8205170478 | |
| Download: ML20051R546 (3) | |
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SAFETY EVALUATION SAN ONOFRE NUCLEAR GENERATING STATION, UNIT 2 00CKET NO. 50-361 Introduction By letter dated April 7,1982 the Southern California Edison Company, the licensee. requested a change to the San Onofre Nuclear Generating Station, Unit 2 Technical Specifications, Sections 4.8.4.1.a.1.b, and Table 3.8-1 (Containment Penetration Conductor Overcurrent Protection Devices) to clarify the testing and acceptance criteria for low and medium voltage circuit breakers and to delete the nominal trip setpoint and short circuit response tine values from the Technical Specifications. The change specifies testing of the low and medium voltage circuit breakers in accordance with the manufacturer's recommendations. Surveillance testing as previsouly required by the Technical Specifications may cause damage to the low and medfun voltage breakers.
Evaluation By letter dated April 7,1982 the ifcensee requested that the nominal trip setpoint and the short circuit response times be deleted from Technical Specification Table 3.8-1 and that testing of these circuit breakers be in accordance with the nanufacturer's recommendations without reference to the short circuit response time. The values for the nominal _ trip setpoint as previously listed repre:ent the short circuit trip setpoint. Testing of these circuit breakers will consist of injecting a current in excess of the breskers' normal setpoint and measuring the response time. The measured response time will be conpared to the nanufacturer's data to ensure that it is less than or equal to a value specified by the manufacturer. These data will be listed in the appropriate station procedures.
These circuit breakers are designed by the manufacturer to respond to an over-current condition with an inverse time delay trip; i.e., the larger the over-current, the sooner the trip occurs after the overcurrent starts. Lower voltage circuit breakers are normally " molded case" type breakers with a thermal-type trip element. While designed to protect circuits from short circuit conditions, these breakers are not designed to be repeatedly tested at short circuit condi-tions. They are, however, designed to be tested at some nominal value above the lowest trip setpoint but below the short circuit trip setpoint and will respond in accordance with the nanufacturer's response time curve. Therefore, if the breakers are tested at or above this nominal value and they respond in accordance with the nanufacturer's specifications, they properly are considered OPERABLE per the Technical Specifications. This amendment clariffes the required methods of testing the Containment Penetration Conductor Overcurrent Protection Devices but does not alter the intent of the Technical Specification nor does this clarification require any alteration of the physical station.
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e Environmental Consideration We have detemined that this 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 envirornental impact. Having made this detemination, we have further concluded that the amendment involves an action which is insignificant from the standpoint of environmental impact and, pursuant to 10 CFR Section 51.5(d)(4), that an environental inpact statenent or negative declaration and environnental impact appriasal need not be prepared in connec-tion with the issuance of this amendnent.
Conclusion Based upon our evaluation of the proposed change to the San Onofre Unit 2 Technical Specifications, we have concluded, that:
(1) because the anendment does not involve a significant increase in the probability or consequences of accidents previously considered, does not involve a significant decrease in a safety nargin, and does not increase the possibility of an accident of a type different than any previously evaluated, the amendment therefore 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 nanner, and (3) such activities will be conducted in compliance with the Comn11ssion'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. We, therefore, conclude that the proposed changes are acceptable.
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Environmental Consideration We have deternined that this amendnent does not authorize a change in effluent types or total amounts nor an increase in power level andyfil not result in any significant environmental impact. llaving made this determination, we have further concluded that the amendment involves an action which is insignificant # rom the standpoint of environmental f#act and, pursuant to 10 CFR Section 51.5(d)(4), that an environmental imfiact statement or negative declaration and environmental impact appriasal need not be prepared in connec-tion with the issuance of this amendment.
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Conclusion
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Based upon our evaluation of the propose'd change to the San Onofre Unit 2 Technical Specifications, we have concluded, that:
(1) because the amendnent does not involve a significant increase in the probability or consequences of accidents previously considered'and 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 with the Connission'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. We, therefore, conclude that'the proposed chances are acceptable.
Dated:
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