ML20072G096
| ML20072G096 | |
| Person / Time | |
|---|---|
| Site: | Wolf Creek  |
| Issue date: | 08/16/1994 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20072G094 | List: |
| References | |
| NUDOCS 9408240196 | |
| Download: ML20072G096 (3) | |
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WASHINGTON. D.C. 20555 @ 01 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 77 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 February 24, 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 TS 4.7.1.2.1.a to require that the turbine-driven and motor-driven auxiliary feedwater pumps be tested at least quarterly on a staggered basis instead of the previously required testing once per 31 days on a staggered basis.
The revised surveillance frequency is consistent with the guidance issued in Generic Letter 93-05, "Line-Item Technical Specification Improvements to Reduce Surveillance Requirements for Testing During Power Operation." The proposed changes also include the Bases to TS 3/4.7.7, Emergency Exhaust System -
Auxiliary Building, and TS 3/4.9.13, Emergency Exhaust System - Fuel Building, to eliminate the reference to the use of automatic control for the emergency exhaust system heaters.
2.0 BACKGROUND
The NRC has completed a comprehensive examination of surveillance requirements in 15 that require testing during power operation.
The evaluation is documented in NUREG-1366, " improvements to Technical Specification Surveillance Requirements," dated December 1992.
The staff found that while the majority of testing at power is important, safety can be improved, equipment degradation decreased, and an unnecessary burden on personnel resources eliminated by relaxing a small fraction of the TS testing intervals.
Based on the results of the evaluations documented in NUREG-1366, the NRC issued Generic letter 93-05. "Line-Item Technical Specifications improvements to Reduce Surveillance Requirements for Testing During Power Operation," dated September 27, 1993.
Section 9.1 of NUREG-1366, discusses the potential advantages of reduced surveillances for the auxiliary feedwater pumps.
As noted in the report, although performance of surveillances is an important mechanism in the identification of problems with the auxiliary feedwater pumps, the testing also contributes to the degradation of the pump and system unavailability.
The analyses used in the report found that a monthly surveillance test interval may be contributing to auxiliary feedwater (AFW) pump unavailability 9408240196 940816 yDR ADOCK 05000482 PDR
i o through failures and equipment degradation. The report recommended a change in the testing frequency to a quarterly interval. Another advantage of the quarterly testing is that it is consistent with the requirements of the ASME Code.
The licensee's request to eliminate the words "using automatic control" in the TS Bases for 3/4.7.7 and 3/4.9.13 is a result of problems encountered with the humidity control feature of the emergency exhaust system heaters.
The heaters were designed to operate, based on input from a relative humidity sensor, to maintain low humidity of the air entering the emergency filter absorber units.
A modification to the fuel building emergency exhaust system was implemented in which the relative humidity sensors were bypassed to allow continuous operation of the heaters whenever the emergency exhaust system fans are operating. A similar modification may be implemented for the auxiliary building emergency exhaust system.
3.0 EVALUATION The change proposed by the licensee regarding an increase in the auxiliary feedwater system surveillance test interval from monthly to quarterly is consistent with the recommendation in NUREG-1366.
In addition to the studies referenced in NUREG-1366, the licensee provided a surveillance history of the auxiliary feedwater pumps at Wolf Creek Generating Station. The operating experience at Wolf Creek was stated to involve no failures of the two (2) motor-driven pumps during 228 tests and five (5) failures of the turbine-driven pump during 132 surveillance tests.
The staff finds the operating history of the pumps to be compatible with the recommended surveillance interval in NUREG-1366.
Therefore, the staff finds the proposed change to the auxiliary feedwater pumps' surveillance test intervals to be acceptable.
The proposed changes to the Bases of TS 3/4.7.7 and 3/4/9.13 are associated with a completed modification to the fuel building emergency exhaust system and a potential modification to the auxiliary building emergency exhaust system.
The change deletes the words "using automatic control" to reflect the bypassing of the relative humidity sensors for heater control.
The heaters-are used to limit the humidity of air entering the exhaust filters.
The design changes involve having the heaters in operation whenever the emergency exhaust systems fans are operating. The modification increases the emergency exhaust system reliability by ensuring the operation of the heaters while the fans are operating, regardless of the humidity level or operability of the humidity sensor.
The revised Bases pages have been incorporated into the Wolf Creek Generating Station Technical Specifications.
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.
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5.0 ENVIRONMENTAL CONSIDERATION
l The amendment changes a surveillance requirement.
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 17610). 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 Contributor:
W. Reckley, NRR Date: August 16, 1994