ML20055D622

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Provides Suppl to Re Loss of All Ac Power.Test Demonstrated That Ventilation Mod & Recalibration of High Temp Trip for Auxiliary Power Diesel Improved Performance of Gas Turbine Generator as Alternate Ac Source
ML20055D622
Person / Time
Site: Point Beach  NextEra Energy icon.png
Issue date: 06/29/1990
From: Fay C
WISCONSIN ELECTRIC POWER CO.
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
CON-NRC-90-062, CON-NRC-90-62 VPNPD-90-305, NUDOCS 9007090196
Download: ML20055D622 (2)


Text

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l' -s e Wisconsin Electnc PONER COMPANY 231 W MscNgan Po Etm 2046. Mdwoukee. WI 63201

( (414)221 2345

. VPNPD-90-305 NRC- 90-062

" June 29, 1990 L

!! Document Control Desk U.S. Nuclear Regulatory Commission Mail Station PI-137 Washington, DC 20555 Gentlemen DOCKET NOS.-50-266 AND 50-301 SUPPLEMENT TO 10 CFR 50.63 RESPONSE, TAC. NOS. 58586 AND 68587 LOSS OF ALL ALTERNATING CURRENT POWER l' POINT BEACH NUCLEAR PLANT, UNITS 1 AND 2 On September 26, 1989, Wisconsin Electric submitted a letter to the NRC that provided additional information about the status of

the gas turbine generator as an alternate AC (AAC) power source for Point Beach Nuclear Plant. In that letter it was stated that-  ;

. the gas turbine building ventilation was considered to be

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inadequate because the auxiliary power d .el, which supplies power to start-and run the gas turbine, would trip due to overheating during testing; A modification was designed and installed-tofimprove building ventilationJnear-the auxiliary; power diesel. Installation of a. .

vent-in the Gas Turbine. Building wall near the. auxiliary power i

diesel was completed,on: June 7,c 1990. On Junel8, another 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> station blackout duration-gas turbine test was performed. The-auxiliary power diesel tripped due .-to the cooling water high-temperature trip after the gas turbine was operated for about 5.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br />.- '

The instrumentation for the auxiliary power diesel was checked, cit was discovered that the high temperature trip was improperly tripping the engine at a temperature about 8'F lower than the setpoint. It was also discovered that the engine temperature gauge was reading approximately 5'F to 10 F high. Therefore, it appeared that the engine.was tripping at its high temperature setpoint when actually it was tripping at a lower temperature.

.The-high temperature trip was recalibrated and raised'an additional 5'F from the previous setpoint setting. The higher -

setpoint is' allowable per the technical manual for the auxiliary power diesel.

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' June 29, 1990 Page 2 3

On June 15, an 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> station blackout duration gas turbine test was successfully performed. The gas turbine was on-line for about 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> and 10 minutes. The 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> test demonstrated that the ventilation modification and recalibration of the high temperature trip for the auxiliary power diesel have improved the performance of the gas turbine generator as an AAC power source at Point Beach. The blackout start testing of the gas turbine will continue on a monthly basis to establish a database to determine its reliability in this mode. As stated in the September 20, 1989 letter, if achievability of 95% reliability cannot be demonstrated within two years of the receipt of the NRC SER on station blackout for Point Beach, the use of the gas turbine generator as an AAC power source will be reassessed at that time.

We would be pleased to answer any questions regarding the above information.

Very truly yours, b

f C. W. Fay Vice President Nuclear Power Copies to NRC Regional Administrator -~ Region III NRC Resident Inspector i

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