ML20210H398
| ML20210H398 | |
| Person / Time | |
|---|---|
| Site: | Summer  |
| Issue date: | 08/08/1997 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20210H396 | List: |
| References | |
| NUDOCS 9708130467 | |
| Download: ML20210H398 (3) | |
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a UNITED STATES 0
NUCLEAR REGULATORY COMMISSION WASHINGTON D.C. 30eeH001
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO.11r, TO FACILITY OPERATING LICENSE NO. NPF-12 l
SOUTH CAROLINA ELECTRIC & GAS COMPANY SOUTH CAROLINA PUBLIC SERVICE AUTHORITY VIRGIL C. SUMMER NUCLEAR STATION. UNIT NO. 1 l
DOCKET NO. 50 395
1.0 INTRODUCTION
in its application dated March 26. 1997. South Carolina Electric & Gas Company (the licensee) proposed that Technical Specification (TS for the two charging /high head safety injection (HHSI) pump cross con)nect valves and the charging pump mini-flow header isolation valve in the emergency core cooling system (ECCS) be revised at Virgil C. Summer Nuclear Station (Summer).
The proposed amendment will add these valves to the list of valves shown on TS Surveillance Requirement (SR) 4.5.2.a.
This amendment re application of the single failure criterion for manually quest is to satisfy controlled electrically operated valves recommended in Branch Technical Position (BTP)
ICSB 18,
2.0 BACKGROUND
The purpose of this amendment request is to satisfy the requirements of a single failure criterion of an electrical system component, which can cause undesirable mechanical motion of the valve or other fluid system component.
Since such a single failure in the ECCS can result in loss of a safety function. Branch Technical Position (BTP) ICSB 18. "Ap)11 cation of the Single Failure Criterion to Manually-Controlled Electrically 4perated Valves."
allows. in lieu of design changes, to disconnect electrical power to the valves, but these valves are to be identified and their required valve
-positions are to be listed in the plant TS.
To satisfy the recommendations of BTP ICSB 18. these valves should be operable from the main control room, and should have redundant position indication in the main control room; the indication system itself shall meet the single failure criterion.
3.0 EVALUATION The licensee proposes to add the following valves 8133A. 8133B. and 8106 as Valve Nos.10.11. and 12. to the valves already listed in TS SR 4.5.2.a for the ECCS, along with its required valve position and its function as follows:
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Valve Number-Valve Function Valve Position
- 10. 8133A Charging /HHSI Cross Connect Open 11, 8133B Charging /HHSI Cross Connect Open
- 12. 8106 Charging Mini Flow Header Isolation Open Since these-valves belong to a subsystem of the ECCS. they are required to be o>erable during a loss of coolant accident. Although the initiation of the E:CS does not require any realignment of these valves from their normal position.-the operator may need.to realign Valves 8133A and 8133B, depending i
on which charging pumps are operating,ld leg recirculation is required.
later in the transient when the switchover from safety injection to co During the injection or recirculation phase of the ECCS. a single failure in the control circuitry could cause a spurious actuation of the valves that may result in loss of a safety function.
The specific concern at Summer is the following: while charging pump C is aligned to train B (i.e.. Valve Nos. 8133A and 81338 are open and connected in series), a " hot short" in the control circuitry of either of these valves could cause a valve to mechanically change its position, and this could
-disable all HHS1 flow through the train B flow path.
To meet the recommendations of BTP-ICSB 18 the licensee will modify Valve Nos. 8133A and l
8133B during the tenth refueling outage (scheduled for October 1997)-to install a power lockout feature that can be controlled from the main control board and a redundant position indication on the main control board that is powered from the opposite train.
Since these modifications would elimiriate a single failure vulnerability that-could result in. spurious actuation of the valves, the staff finds that the proposed modification of Valve Nos. 8133A and 8133B to install a power lockout feature for these valves and redundant position indication is consistent with BTP ICSB 18.
By adding these valves to TS SR 4.5.2.a. their required valve positions would be verified with power to the valve operator removed once every 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.
As part of the resolution of NRC Bulletin 86-03, the licensee completed the modification for Valve No. 8106 in 1988.
Currently the licensee verifies that power-is removed from the valve once every 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and the valve position is logged once every 31 days as part of the valve lineup.
Since-Valve No. 8106 already meets the recommendations of BTP ICSB 18, it is only necessary to add Valve No. 8016 to TS SR-4,5.2,a.
The staff concludes that-the proposed addition of Valve Nos. 8133A. 8133B, and 8106 to the list of valves-in TS SR 4.5.2.a. which requires these valves be verified "open" with the power to the valve operators removed once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. is acceptable.
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4.0 STATE CONSULTATION
In accordance with the Comission's regulations, the State of. South Carolina official was notified of the proposed issuance of the amendment. The State official had no comments.
5.0 ENVIRONMENTAL CONSIDERATION
The amendment changes a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20.
The NRC staff has determined that the amendment involves no significant increase in the amounts, and no significant change in the types, of any effluent that may be released offsite. and that there is no significant increase in individual or cumulative occupational radiation ex)osure.
The Commission has previously issued a proposed finding that tie amendment involves no significant hazards consideration, and there has been no public comment on such finding (62 FR 27801). Accordingly. the amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9). Pursuant to 10 CFR 51.22(b) no envirunmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendment.
6.0 CONCLUSION
The Commission has concluded based on the considerations discussed above, that:
(1) there is reasonable assurance that the health and safet of the public will not be endangered by operation in the proposed manner.y(2) such activities will be conducted in compliance with the Commission's regulations.
and (3) the issuance of the amendment will not be inimical to the common-defense and security or to the health and safety of the public.
Principal Contributors:
Peter Kang Amritpal Gill Date:
August 8.1997 i
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