ML20034A068
| ML20034A068 | |
| Person / Time | |
|---|---|
| Site: | Wolf Creek  |
| Issue date: | 04/02/1990 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20034A061 | List: |
| References | |
| NUDOCS 9004190261 | |
| Download: ML20034A068 (3) | |
Text
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i SAFETY EVALUATION BY_THE OFTICE OF HUCLEAR REALTOR REGl'LAT10h l
RELATED TO AMENDMENT NO. 38 TO FACILITY OPERATING LICENSE NO. NPF-42 WOLF CREEK NUCLEAR OPERATING CORPORATION WOLF CREEK GENERATING STATION DOCKET NO. 50-482 INTRODUCTION The Pcif Creek Generating Station (WCGS) service water system consists of the Service Mater System and the Essential Service Water System. The Service Water Systcra it c tonsafety-relatcd syster. which provides a scurce of heat removal fer plant auxiliaries that recuire cooling during norrral plant operatiu. and nornel plar.t shutdcwns. This systen also supplies cooling water to the safety-related Essential Servicc Water System during normal plant operation. The Essentiti Service Water Syster provides a source of heet terrevel for safety-related ec,uipr.ent during ard fo11 ewing Design Lasis i
Accidu.ts.
l The WCGS service water syster includes four containtcr.t fan cooler units thtt cre uscd for both normal cperations and for accident cerditiens. The nonsefety-related Service Water Systera supplies cooling water to the fer cc>olors during torr..a1 operctions to ensure. that the centaintert air temperature will be maintained less than 100'F per Technical Specification 3.6.1.5.
In addition, thesLfoty-relatedEssenticiServiceWaterSystemsuppliesecolingwater(viaa differer.t set of pumps) to tht fan coolers during accident conditicnseto ensure that adequate ccrttint.ent heet remeval capt. city is available.
A ccrcern of the 1:RC staff has httn the long-terra degradatier cf beat renoval systems served by open-cycle service water systems.
In particular, Recorcended Action III of Cereric Letter 09-13 discussed establishment of a routioc inspection crd meintenance prcgran for open-cycle scryice water piping and components to ensure that corrosion, crosion, protective coating failure, silting and biofouling cannot degrade the performance of safety-related systems supplied by service water.
Due to both the 1:FC's concerns and previous ccrar.itments nade by the licensee rcgtrding the crosion potential of service water systen pipir.g. the licensee has schtduled major modifications of the service water systems for the Refuel IV (Spring 1990)cutage. The modifications are intended to increase and redistribute the total flow of the Service Water System. The redistribution of flow decreases ficw to some components and increases flew to other components initially on standby (i.e., stegnant conditiers) in order to rainimizc Microbiological 1y InducedCorrosion(MIC).
In addition, the mcdifications are intended to increast back pressure in the system to reduce the potential for previcus problers resulting from erosion.
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I Ey letter dated February 7,1990, the licensee proposed revising Technicel Specification 4.6.2.3.a.2 by reducing the minimum flow rate to each group of two containment fan coolers from 2200 gpm to 1850 ppn. The proposed change, which will result from the scheduled system modifications, will only affect ficw during normal operations. Flow rates durir.g accident conditions are not being changed.
EVALUATION Technical Specification 3/4.7.5 prohibits plant operation if the temperature of the ultimate heat sink (used by both the Service Water System and the Essential Service Water System) exceeds 90'F.
This limit is needed because the Essential Service Water System components were designed to 95'F. This asser.ption conservatively assumes that the ultinate heat sink is et the maximum 90*F whcn the eccident occurs end the subsequent heat loads increase the everall heat sink temperature to 95'F.
Flow reductions without loss of heat removal capebility are possible because the Service 6!ater System components were also designed assuming an inlet ternperature of 95'F.
Calculations by the licensee indicate that the current flow rate of 2200 gpm at 95'F can be reduced to 1850 gpm if the inlet water temperature is assumed to be the technical specification limit of 90*F as eppesed to the desien limit of 95'F. The licensee has also indicated that flow velocities associated with 1050 gpm are greater than 3 feet per second which minimizes sedimentation buildup of entrained particles and corrosion products in piping and components. This, in turn, will help to minimize concerns essociated with MIC.
The proposed changes by the licensee will not change the overell heat removal cepebility of the Service Water System during plant operations and shutdowns.
While the flow rates to the containment fan coolers are being reduced Technical Specificaticn S.6.1.5 renains unchanged and centinues to require that containment air temperatures remain below 120*F. The Essential Service Water System flow rates to the containment fan coolers do not change thus ensuring that accident heat removal capabilities remain unchanged.
In addition, the surveillarce requirement of Technical Specification 4.6.2.3 will continue to provide assurance that containment air cooler cooling water flow degradation will be-identified and corrected in a timely manner consistent with the flow indications obtained. Therefore, based on cur review cf the licensee's submittal, we find the proposed changes to be acceptable.
ENVIRONMENTAL CONSIDE, RATION The amendment involves a change in a requirement with respect to the installa-tion or use of a facility component located within the restricted area as defined in 10 CFR part PO e.nd changes in surveillerte requirements.
The staff has determined that the amendment involves no significant increase in the.
an.ounts, and oc significant change in the types, of any effluents-that may be released offsite, and that there is r.o significant increase in individual or cumulativc occupationel radiation exposures. The Commission has previously issued a proposed finding thet the amendment involves no significant hazards
o consideration and there has been no public comment on such finding. Accordingly, the amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR Section 51.22(c)(9).
Pursuantto10CFR51.22(b),noenvironmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendment.
CONCLUSION The staff has concluded, based on the considerations discussed above, that:
(1) there is reasonable assurance that the health and safety of the will not be endangered by operation in the proposed manner, and (2) public-such activities will be conducted in compliance with the Commission's regulations, and the issuance of the amendnent will net be inimical to the common defense and security or to the health and safety of the public.
Date:
April 2,1990 Principal Contributor:
D. V. Pickett, PDIV i
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