ML20072F925
| ML20072F925 | |
| Person / Time | |
|---|---|
| Site: | Wolf Creek  |
| Issue date: | 08/16/1994 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20072F924 | List: |
| References | |
| NUDOCS 9408240126 | |
| Download: ML20072F925 (3) | |
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-...f SAFETY EVALVATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 78 TO FACILITY OPERATING LICENSE NO. NPF-42 WOLF CREEK NUCLEAR OPERATING CORPORATION WOLF CREEK GENERATING STATION DOCKET NO. 50-482
1.0 INTRODUCTION
By application dated April 19, 1994, Wolf Creek Nuclear Operating Corporation (the licensee) requested changes to the Technical Specifications (Appendix A to Facility Operating License No. NPF-42) for the Wolf Creek' Generating Station.
The proposed changes would revise Technical Specification Table 3.6-1, " Containment Isolation Valves," by deleting the reference to two (2) valves. The technical specification change reflects a planned modification which removes the essential service water (ESW) containment air cooler return line isolation valve bypass valves and associated piping.
2.0 BACKGROUND
The Wolf Creek ESW system provides cooling water flow to the containment air coolers in the event of a high energy line break.
The flow path to the coolers require containment penetrations for the ESW supply and return lines.
Each ESW containnicat penetration for these lines is provided with isolation valves on each side of the containment wall. The ESW system was originally designed with bypass lines (each with an isolation valve) around the ESW containment isolation valves EF-HV-49 and EF-HV-50 on the return lines from the containment air coolers, outside of containment, to accomodate variations in system load.
The original system design required the bypass valves to be open to pass 2000 gpm with the ESW containment isolation valves opening on a safety injection signal to increase the ESW flow to the containment coolers to 4000 gpm.
A license amendment request and supporting analyses were submitted in June 1991 to reduce the required ESW flow to the containment coolers.
This reduction in flow to the containment coolers allowed additional post-LOCA ESW flow to other safety related components. The revised requirements for ESW flow to the containment coolers was issued as License Amendment 50 on November 4, 1991.
The reduced post-LOCA ESW flow requirements to the containment coolers was such that the bypass lines around the ESW containment-isolation valves are no longer required. The normal and post-LOCA flows are equal at approximately 2000 gpm.
The planned modification involves the removal of the 10" bypass valves and the installation of backpressure orifices.
Control of the ESW flow to the containment coolers will be acheived by the combination of the backpressure orifices and throttling of the 14" ESW 9408240126 940816 PDR ADOCK 05000482 P
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containment isolation valves.
In addition, the modification includes the replacement of the existing carbon steel isolation valves with stainless steel valves to address erosion / corrosion concerns. The proposed amendment is required to support the modification because the bypass isolation valves are currently included in the 1S Table 3.6-1 list of containment isolation valves.
3.0 [VALVATION The design objective of the containment isolation system is to allow the normal or emergency passage of fluids through the containment boundary while preserving the ability of the boundary to prevent or limit the escape of firsion products during postulated accidents.
In the case of the ESW return linas from the containment coolers, the containment isolation function for ea;h ESW train is provided by an isolation valve inside containment, an isolation valve outside containment (EF-HV-49 or EF-HV-50), and a bypass isolation valve for the line arounJ the outside isolation valve.
The need for the combination of outside isolation valves and bypass valves to control ESW flow was negated by the reduction in required ESW flow to the containment coolers which was approved in License Amendment 50.
The licensee plans to utilize the isolation valve and a backpressure orifice to control ESW flow to the containment coolers and remove the bypass valve and associated piping.
The removal of the bypass valve necessitates a TS change because the bypass valves are listed in TS Table 3.6-1, " Containment Isolation Valves."
Following the planned modification to the ESW system removing the bypass isolation valves and associated piping, isolation capability will be maintained by the remaining two containment isolation valves per ESW train.
Leak testing of the containment penetrations and associated isolation valves will ensure that they adequately prevent or limit the release of radioactive material from containment in the event of an accident. A net safety improvement may be acheived by the removal of a potential leakage path through the bypass lines and bypass isolation valves.
The staff finds the proposed change acceptable.
4.0 STATE CONSULTATION
In accordance with the Commission's regulations, the Kansas State 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 effluents that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure.
The Commission has previously issued a proposed finding that the amendment involves no significant hazards consideration, and there has been no
public comment on such finding (59 FR 32239). 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 environmental 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 safety of the public will not be endangered by operation in the proposed manner, (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 Cont-ibutor:
W. D. Reckley Date: August 16, 1994