ML20137L014

Confirms That All Qualification Programs Re Seismic & Pump & Valve Operability Completed in Accordance W/Approved Stds. Installation Concern Re in-core Thermocouple Circuits Does Not Constitute Unreviewed Safety Question

ML20137L014
Person / Time
Site:	Wolf Creek, Callaway, 05000000
Issue date:	11/27/1985
From:	Petrick N STANDARDIZED NUCLEAR UNIT POWER PLANT SYSTEM
To:	Harold Denton Office of Nuclear Reactor Regulation
References
SLNRC-85-23, NUDOCS 8512030339
Download: ML20137L014 (3)

Text

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SNUPPS Stenderdized Nuclear Unit Power Plant System 5 Choke Cherry Road Nicholas A. Petrick Rodville, Maryland 20850 Executive Director

• • • • • • " November 27, 1985 SLNRC 85-23 FILE: 0278/8021 SUBJ: Seismic Qualification of Equipment and Operability Qualification of Pumps and Valves Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Docket Nos.: STN 50-482 and STN 50-483

References:

1. Safety Evaluation Report Related to the Operation of Callaway Plant, Unit No.1, NUREG-0830.

2. Safety Evaluation Report Related to the Operation of Wolf Creek Generating Station, Unit No.1, NUREG-0881.

3. SLNRC 84-0101, dated 6/29/84: Equipment Qualification Justifications for Interim Operation (JIO).

4. SLNRC 84-0102, dated 7/16/84: Justifications for Interim Operation--Seismic Qualification.

Dear Mr. Denton:

Supplement No. 4 to Reference 1 and Supplement Nos. 5 and 6 to Reference 2 require written confirmation that the qualification programs, for all equipment whose seismic and pump and valve operability qualification was based on a Justification for Interim Operation (JIO), have been completed in accordance with approved regulatory standards, and qualification files have been updated accordingly. As noted in References 3 and 4, the JI0's applicable to seismic and pump and valve operability qualification provide sufficient documentation to demonstrate qualification to approved regula-tory standards. The reliance on JI0's as a basis for qualification was l necessitated because the documents which describe seismic and pump and valve operability-related testing were the same documents being reviewed in detail by the Westinghouse User's Group for Equipment Qualification and by the SNUPPS Utilities to demonstrate compliance with the requirements of )

10 CFR 50.49. Since the qualification documents could not be approved )

until the environmental qualification review was completed, sufficient I details relative to seismic and pump and valve operability qualification were incorporated into the JI0's.

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0t 8512030339 851127 PDR ADOCK 05000482 P PDR ,

SLNRC 85- 23 Page Two This letter confirms that all qualification programs related to seismic and pump and valve operability, as identified in References 1 and 2, have been completed in accordance with approved regulatory standards, and that utility equipment qualification files have been updated with the approved documents for both Callaway Plant and Wolf Creek Generating Station.

During site verification of equipment installation at Callaway Plant, it was determined that the incore thermocouple circuits near the reactor vessel head had not been installed in a manner consistent with the seismically tested configuration. The tested configuration used metal straps to restrain the themocouple circuits; whereas, at Callaway Plant, organic cable ties were used. Therefo e, it may be postulated that a seismic event could render the incore themocouple sytem inoperable. Upon discovery of this situation, a safety evaluation was performed. The following information was considered in the evaluation:

1. The incore thermocouple system is a post-accident monitoring system and does not automatically initiate any plant safety functions.

2. The safety function of the thermocouple system is to detect inadequate core cooling (ICC) which would accompany a loss of reactor coolant.

Based on the background information for the Westinghouse Owner's Group Emergency Response Guidelines, for an ICC . situation to exist, the loss of coolant would have to be more severe than any design basis events previously analyzed in the Callaway Final Safety Analysis Report.

3. In section 18.2.13 of the Final Safety Analysis Report, the thermocouple system is identified as Class 1E which, by definition, requires seismic qualification. However, the system is not required to mitigate a seismic event nor is it required to achieve a safe shutdown condition following a seismic event.

4. Callaway Plant Emergency Operating Procedures require the use of incore thennocouple readings by plant operators to detect ICC and initiate appropraite mitigating actions. For this purpose, the thermocouple system must be operable from the time a loss of coolant event occurs until the onset of ICC which would, at most, be a few hours. It is highly unlikely that a seismic event would occue during this brief period of time.

Based on the evaluation, it was concluded that the installation concern did not constitute an unreviewed safety question. Also, because the thermocouple system is capable of performing its safety function following a loss of coolant accident, it was concluded that the system was operable as defined in the plant Technical Specifications. Therefore, it was determined that Callaway Plant could be safety operated until the first refueling outage when the incore thermocouple circuits could be modified to match the tested configuration. Steps have been initiated to procure the necessary material

SLNRC 85-23 Page Three

.and implement the design changes to the thermocouple system at the first refueling outage for Callaway Plant which is currently scheduled to commence in March 1986.

Ver tr ly yours,

. N, cholas A. Patrick' MHF/dck/2a8 cc: G. L. Koester KGE J. M. Evans KCPL D. F. Schnell UE B. Little USNRC/ CAL J. Cummins USNRC/WC G. C. Wright USNRC/RIII E. H. Johnson USNRC/RIV 9