ML20246F648

Safety Evaluation Accepting Proposed Turbine Sys Maint Program

ML20246F648
Person / Time
Site:	Perry
Issue date:	08/23/1989
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML20246F642	List: ML20246F638 ML20246F648
References
NUDOCS 8908310097
Download: ML20246F648 (2)

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t,_ cv i I' hn CEQq%, UNITED STATES 3 ~j NUCLEAR REGULATORY COMMISSION l g ,p WASHINGTON, D. C. 20555 k.%...+[ l i

_ SAFETY EVALUATION BY THE OFFICE OF NUCLEAR ?EACTOR REGULATION j RELATED TO THE TURBINE SYSTEM MAINTENANCE' PROGRAM FOR THE PERRY NUCLEAR POWER PLANT, UNIT NO. 1 DOCKET NO. 50-440

1.0 INTRODUCTION

By letter cated March 20,'1989, the Cleveland Electric Illuminating Company (licensee) submitted a turbine system maintenance program in response to a license condition described in Supplement 3 to the Perry Safety Evaluation Report (SSER No. 3), NUREG-0887. In Section 3.5.1.3.3 of-SSER No. 3, the staff required the licensee to submit a turbine system maintenance program within 3 years of licensing based on the turbine manufacturer's calculations of turbine missile generation probability. Until the prograra is approved, the licensee is required tu conduct turbine system inspections based on the schedule specified in Section 3.5.1.3.1.5 of SSER No. 3. In USAR Ame9 ament 23, Appendix IB, the licensee committed to perform the turbine syster maintenance and provice the maintenance program as required which was acceptable to the staff for deleting the license condition as stated in SSER No. 8.

2.0 DISCUSSION The licensee's submittal provides the turbine missile generation prob-ability for each of the three low pressure turbines and a proposed inservice inspection and maintenance program for the low pressure turbine assembly. The licensee calculated the turbine missile generation probability using the General Electric methodology described in the report, " Probability of Missile Generation in General Electric Nuclear Turbines." The staff had previously approved the GE methodology and recommended its use in establishing maintenance and inspection schedules for all GE nuclear turbines.

The Perry turbine is unfavorably orientated with respect to the reactor building; that is, there are safety-related targets inside the low trajectory missile strike zone. Based on the unfavorable orientation,

-the staff requires that the turbine missile generation probability be less than IE-5 per year.

The licensee reported that based on a 6-year inspection schedule, the

, turbine missile generation probability for all three low pressure turbines was 6.2E-6 per year. The turbine missile generation probability for each of the low pressure (LP) turbines is as follows: LPA, 2.7E-6; LPB, 1.1E-6; and LPC,-2.4E-5.

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. - , n' The licensee'will perform visual, surface and volumetric inspections of.

l each LP turbine within a 6-year period of actual turbine operation at different refueling outages. This schedule will correspond with four refueling cycles each consisting of 18 months. Besides LP turbine inspections, the licensee will also inspect the high pressure turbine at about 10-year intervals. The program will include disassembly of the LP turbine and inspection of couplings, coupling bolts, turbine shaft, LP turbine buckets, LP turbine wheels, and high pressure turbine rotors. The examination will include the following:

a. A volumetric examination of LP turbine wheels and high pressure turbine rotors including keyways and bores,

b. Visual examination of accessible surfaces of wheels and rotors.

c. Visual and surface examination of LP turbine buckets.

d. 100% surface examination of couplings and coupling bolts.

Besides the turbine examinations, the licensee will also inspect the turbine-steam valves and overspeed trip mechanism, which are a part of the turbine overspeed protection system, as specified in the Perry Technical Specifications Section 4.3.8.2.

3.0 CONCLUSION

Based upon the discussion above, the staff concludes that the licensee's turbine missile generation probability and turbine system maintenance progran are acceptable and license commitment #4 of Appendix IB to the Updated Safety Analysis Report (USAR) has been satisfied. The licensee's proposal to revise the Perry USAR Section 10.2.3.6, " Inservice Inspection and Maintenance Program," is also acceptable and may be incorporated into the Perry USAR.

Principal Contributor: John Tsao

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