05000354/LER-2004-004, Non-Conservative 4160 Volt Class 1E Bus Operating Limits

Non-Conservative 4160 Volt Class 1E Bus Operating Limits

ML041730442
Person / Time
Site:	Hope Creek
Issue date:	06/03/2004
From:	Hutton J Public Service Enterprise Group
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
LR-N04-0245 LER 04-004-00
Download: ML041730442 (6)

LER-2004-004, Non-Conservative 4160 Volt Class 1E Bus Operating Limits

Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(v), Loss of Safety Function
3542004004R00 - NRC Website

text

PSEG Nuclear LLC

_ _P.O.

Box 236, Hancocks Bridge, New Jersey 08038-0236 I

oI PSEG Nuclear LIC LR-N04-0245 JUN 0 3 2004 U. S. Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 LER 354/04-004-00 HOPE CREEK GENERATING STATION FACILITY OPERATING LICENSE NO. NPF-57 DOCKET NO. 50-354 This Licensee Event Report entitled "Non-Conservative 4160 Volt Class 1E Bus Operating Limits" is being submitted pursuant to the requirements of 1 OCFR50.73(a)(2)(v)(D).

Sincerely, ames utton Plant Manager - Hope Creek Attachment BJT C

Distribution LER File 3.7

'D'__1,

95-2168 REV. -

Abstract

On April 5, 2004, a review of electrical design calculations identified that Operations procedures contained non-conservative values for minimum voltage on the Class 1E 4160 volt buses. The design calculations demonstrate that if voltage on the Class 1 E 4160 volt buses are maintained above the minimum analyzed bus voltage level in the calculations, the 4160 volt buses would provide sufficient voltage to start and maintain the running loads without separating from the offsite power source. These calculations were performed to demonstrate compliance with I OCFR50 Appendix A General Design Criteria 17, 'Electric Power Systems," and Branch Technical Position PSB-1,

• Adequacy of Station Electric Distribution System Voltages.' Operating logs and procedures used to monitor the 4160 volt Class 1 E buses would have allowed the buses to operate below the minimum voltage analyzed in the calculations. In addition to the non-conservative minimum bus voltage in the operating logs, the review of the calculations also identified that the automatic load tap changer (LTC) was set to maintain voltage at a 'nominal 4200 volts minimum". At a setpoint of 4200 volts, the LTC was not capable of maintaining the minimum bus voltage assumed in the calculations when setpoint inaccuracies are taken into account.

The cause of this event is attributed to inadequate program detail that resulted in an inadequate program to program interface between design calculations and implementing procedures. An Operability Determination was generated to establish the required minimum bus voltage, including instrument inaccuracies, and to operate the load tap changers manually to maintain the buses above the new limit. Additionally, Operating procedures were revised to reflect the new voltage limits and administrative procedures will be revised to address the interface between design calculations and implementing procedures.

This event is being reported in accordance with 10CFR50.73(a)(2)(v)(D), any event that could have prevented the fulfillment of the safety function of structures or systems that are needed to mitigate the consequences of an accident.

, NM,-

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CORRECTIVE ACTIONS(cont'd):

5. Procedure NC.DE-AP.ZZ-0002, "Engineering Calculations and Analyses," will be revised to include a requirement that calculations contain an implementing procedure cross reference section.

6. Procedures NC.DM-AP.ZZ-0001, "Procedure Administrative Process," and NC.NA-WG.ZZ-0001, "Procedures Writers Guide," will be revised to instruct procedure writers to contact Engineering when values are being changed in procedures that are associated with setpoints or operating bands.

The actions specified above are being tracked in accordance with PSEG Nuclear's Corrective Action Program.

COMMITMENTS

The corrective actions cited in this LER are voluntary enhancements and do not constitute