ML20236J212

Safety Evaluation Accepting Util Turbine Sys Maint Program

ML20236J212
Person / Time
Site:	Limerick
Issue date:	11/03/1987
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML20236J195	List: ML20236J193 ML20236J212
References
NUDOCS 8711050192
Download: ML20236J212 (2)

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M Katg'ok UNITED STATES lY ~i' NUCLEAR REGULATORY COMMISSION

$ ' WASHINGTON, D. C. 20555 k.....

SAFETY EVALUATION BY'THE OFFICE OF NUCLEAR' REACTOR REGULATION' TURBINE SYSTFM MAINTENANCE PROGRAM PHILADELPHIA ELECTRIC COMPANY LIMERICK GENERATING-STATION,' UNIT 1 DOCKET NO. 50-352  ;

1.0 INTRODUCTION

By letter dated May 26,:1987,- Philadelphia Electric Company submitted a -

o maintenance program for the low pressure turbines to satisfy License.

' Condition'2.C.(9).of Facility Operating License NPF-39 at Limerick Unit

1. The license condition requires the licensee to submit a turbine

maintenance' program by October 26, 1987. o

'To assure reasonable safe. turbine operation the staff requires the licensee to follow the manufacturer's turbine maintenance program 1 -including turbine inspection-intervals based on a NRC approved method.

The. turbine' inspection, interval should be calculated such that the corresponding. turbine missile probability must be maintained to 1E-5 per year .for an unfavorably oriented turbine and IE-4 per year for a favorably oriented turbine. A favorable orientation is when the turbine

~s haft is located radially from the axis of the reactor building. The turbine shaft' at Limerick is located in a vertical plane that is parallel toLthe axis of. the reactor building and, therefore, unfavorably oriented.

Given the criterion for the missile generation probability, the licensee must calculate the turbine inspection interval taking into account turbine operating' conditions, material properties of discs, and other factors.

The licensee- reported that the missile generation probability of each low pressure turbine is less than IE-5 per-year when each turbine is inspected every six' years at. Limerick. These values were obtained from a Generic Electric (GE) analysis which was approved by the staff (Ref. NUREG-1048, Safety Evaluation Report related to the Operation of Hope Creek ,

Generating Station, Supplement No. 6. July, 1986.)

2.0 EVALUATION The licensee will follow GE's reconenended turbine maintenance program which includes volumetric examination of the low pressure disc, visual and surface examination of the low pressure buckets, and visual examination of accessible surfaces of rotors and discs. The program also includes inspection of valves that are associated with turbine operation such as main steam stop and control valves and combined intermediate valves.

The licensee has demonstrated use of an acceptable methodology to calculate the turbine missile probability versus inspection interval and a711050192 PDR. ADOCK h hPDR 52 P

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, has committed to use-:the manufacturer's recommendations for the turbine l maintenance program. .The staff concludes that the-turbine maintenance l~ program.at Limerick Urit ~1 is' acceptable and satisfies License -

Condition 2.C.(9);

Principal Contributor:' J. Tsao

!~ Datedi - November 3,1987 I

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