ML20077N069

Application for Amends to Licenses DPR-24 & DPR-27, Consisting of TS Change Request 146,revising Spec 15.A.6.A.2 Re Emergency Power Sys Periodic Tests

ML20077N069
Person / Time
Site:	Point Beach
Issue date:	08/09/1991
From:	Fay C WISCONSIN ELECTRIC POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20077N072	List: ML20077N069 ML20077N076
References
CON-NRC-91-078, CON-NRC-91-78 VPNPD-91-270, NUDOCS 9108140199
Download: ML20077N069 (4)

Text

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Wisconsin Electnc POWER COMPANY 231 W Meren to fr. ma uwco a smi W W 2M5 VPH PD 27 0 10 CFR 50.59 NRC 07 8 10 CFR 50.90 l 10 CFR 50.4 August 9, 1991 U. S. NUCLEAR REGULATORY COMMISSION Document Control Desk Mail Station P2-137 Washington, D. C. 20555 i

Gentlemen DOCKETS 50-266 AND 50-301 TECHNICAL SPECIFICATION CHANGE REOUEST 146 EMERGENCY POWER SYSTEM PERIODIC TESTS POINT BEACH NUCLEAR PLANT, UNITS 1 AND 2 In accordance with the requirementslof 10 CFR 50.59 (c), 50.90, and 50.4, Wisconsin Electric Power Company (licensee) hereby requests amendments to Facility Operating Licensts DPR-24'and DPR-27 for Point Beach Nuclear Plant, Units 1 and.2 respectively, to incorporate changes into the plant Technical Specifications.

l The proposed change will revise specification 15.4.6.A.2 to eliminate the requirement that, during testing, the emergency diesel generator start and assume-loads in less than the time periods listed in the Point Beach Nuclear Plant Final Safety

Analysis Report (FSAR) and replace it with the requirement that the loads be assumed in the timing sequence listed. A marked-up Technical Specification page with the changes included is attached.

Point. Beach Technical Specification 15.4.6.A.2 requires a test of the automatic start of each diesel generator, load shedding, and restoration-of particular vital equipment, initiated by an actual interruption of AC power to emergency safety feature (ESP) buses

! with a simulated safety injection signal. The acceptance l criterion defined in the specification requires that the diesel' l generator start and accept loads in less than the FSAR-specified' times. This criterion has existed since the issuance of the operating license for each unit. This acceptance criteria could allow a situation where sequencing on consecutive loads could overlap, resulting in a transient overload of the diesel l

generator.

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N'RC Document Control Desk l August 9, 1991 Page 2 The load sequence times listed in Section 8.2 of the FSAR are  ;

conservative with respect to the maximum times assumed in the accident analyses documented in Chapter 14 of the Point Beach FSAR. In general, the FSAR requires the assumed loads to sequence on at five-o cond intervals. The five-second interval was specified in the sriginal diesel generator specification.

In 1985, when incorporating an unrelated change to our Technical Specifications, the phrase "in less than the time period listed in" was inadvertently deleted from this specification. We discovered eqd corrected this error during the first half of 3990. This incident is documented in Inspection Report 50-266/90010(DRP) ; 50-301/90010(DRP) dated June 26, 1990.

Without this critorion for load start times to be less than that listed in the FSAR in the Specification, we interpreted Specification 15.4.6.A.2 to allow load sequencing in accordance with the FSAR times within appropriate tolerances. The tolerances which were impicmented in our test procedures during this period ensured that, under worst caso conditions, no load would sequence on within one second of the previous load starting. Test data during this period indicate that a one-second interval is sufficient for diesel generator voltage and frequency to recover prior-to the next load starting. Maximum t allowable start times remained within the FSAR accident analyses latest assumed start times for the appropriate loads.

Accordingly, we propose to modify Technical Specification 15.4.6.a.2 to read in part, " ...This test will be conducted during reactor shutdown for major fuel reloading of each reactor to assure that the diesel generator will start and assume required load in accordance with the timing sequence in FSAR Section 8.2." We will also modify FSAR Section 8.2 with our next update to specify that appropriate tolerances are placed on the load sequence times to prevent a transient overload of the diesel generator.

We have evaluated this change in accordance with the requirements of 10 CFR 50.91 (a) against the standards in 10 CFR 50.92 and have determined that the operation of Point Beach Nuclear Plant Units 1 and 2 does not result in a significant hazard.

Previously analyzed accidents considered in this determination include Loss of Coolant, Loss of Normal Feedwater, and Steam Line =

Break. Also considered was the " Containment Performance Evaluation" in_ Chapter 14 of the Point Beach FSAR. Our evaluation against each of the criteria in 10 CFR 50.92 and basis for our "no significant hazards" determination follows.

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NRC Document Control Desk August 9, 1991 Page 3 criter.lon 1 Operation of a facility in accordance with a proposed amendment does not prosent a significant hazard if it does not result in an incroano in the probability or consequences of an accident previously evaluated.

The prosent requiremont that loads sequence on the diosol generator in timos loss than thoso listed in the FSt.R could result in two or more major loads sequencing onto the diosol at the same tino or prior to nonorator voltago and frequency recovering following the eart of an earlier load. This presents the possibility of overloading the generator, resulting in generator trip and unavailability of systems and components necessary for accident mitigation, thoroby increasing the probability or consequences of an accident. Dy establishing appropriato tolerancos on the load sequence timos, assurance is ,

gained that sufficient timo is allottod betwoon equipment starts to allow generator voltago and frequoney to return to nominal I system voltago and frequency. This docreases the possibility of a transient diosol overload. Maximum start times including the tolerancos will remain within tho tf.mos assumed in the FSAR analyson. Test frequencios or conditions for the diosol gonorators will not chengo. Overall, since the probability of a diosol generator overload docroanos while maintaining assurance that the diosol generator will start and loads energize within the maximum times proscribed by accident analysos, the probability or consequences of accidents previously analyzed will decrease.

Criterion 2 Operation of a facility in accordanco with a proposed amendment does not prosent a significant hazard if it cannot create the possibility of an accident different from any previously evaluated.

This change does not result from any physical change to the facility or its operation. The operability of equipment that is necessary for safe shutdown or accident provention and mitigation is not affected. Testing intervals for the diopol generator will not chango; so adequato assurance of diesel generator and system operability is maintained. Load sequence timco will remain within conservativo accident analyses assumptions, and added assurance is provided that an generator overload will not occur.

Thorofore, a not' or different kind of accident cannot result, i

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NRC Document Control Desk August 9, 1991 Page 4 Critorion 3 operation of a facility in accordance with a proposed amendment will not present a significant hazard if it does not result in a significant reduction in a margin of safoty.

The surveillance interval for testing the diosol generator and its capability to assumo loads required for accident mitigation are not changed. Continued assurance of generator and system operability under scenarico of an accident coupled with a loss of off-site AC power is maintained. This acceptanco critorion for load sequence timos providos added assuranco that a gonorator overload condition will not occur while maintaining load sequence times within accident analysos assumptions. This may provido an added margin of safety under conditions where a diosol generator is required to assume accident loads. Thorofore, a margin of safety cannot be reduced and may be increased.

If you have any questions about this proposed amendment or 10 CFR 50.91 ovaluation, please contact us. Wo bolieve that the proposed amendments will enhanco the safe operation of the Point Beach units and request they be processed accordingly.

'Very truly yours EN;fv

/

C. W. Fay /

Vice President Nuclear-Power

. Attachment copios to NRC Regional Administrator, Region III NRC Resident Inspector Subscribed and sworn to hofore me this 4th day of /h4,..J 1991.

A o A NAfr. ct .<

Notary Public, State of Wisconsin My Commission expires C-22 -if.