ML20045H504

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Provides Addl Info to Support NRC Review of ASME Section XI Relief Request 2014 (Rev 3) Re Testing of Testable Check Valves
ML20045H504
Person / Time
Site: Clinton Constellation icon.png
Issue date: 07/13/1993
From: Phares R
ILLINOIS POWER CO.
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
U-602153, NUDOCS 9307200300
Download: ML20045H504 (2)


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Ilknois Power Company Chnton Power Station P.O Box 678 Chnton, IL 01727 Tel 217 935-8881 iLLIN9IS tuous3 POWER L30-93< 0713)LP 8E.100C July 13, 1993 Docket No. 50-461 Document Control Desk Nuclear Regulatory Commission Washington, D.C. 20555

Subject:

Clinton Power Station (CPS)

Additional Information to Support NRC Review of ASME Section XI Relief Req.. cst 2014 (Revision 3) Regarding Testing of Testable Check Valves

Dear Sir:

The purpose of this letter is to provide additional information to assist in the NRC StafTs review of ASME Section XI Relief Request 2014 (Revision 3) concerning testing of testable check valves at CPS. The additional information is provided as requested by the NRC during a telephone conference conducted with Illinois Power (IP) on March 25,1993 to discuss the relief request. During the telephone conference, the NRC specifically asked for additional information on why IP intends to remove the actuators on testable check valves 1E12-F041 A/B/C,1E21-F006, and 1E22-F005.

The benefits of removing the actuators from the testable check valves are 1) potentially improved check valve leak rates, 2) reduced maintenance, and 3) reduced radiation exposure for maintenance personnel. Discussions with other utilities that have performed this modification indeed indicate a better local leak rate testing (LLRT) success rate can be achieved by remov'mg the actuators. We believe this is because the actuator shall and limit switch shaft, with its packing arrangement, may inhibit dise closure using LLRT test pressures.

A review of the CPS maintenance history data base shows that 79% (137 of173) of all maintenance requests generated for these five testable check valves addressed the valve actuators or associated components (solenoids, air supply, etc.). The removal / reinstallation of an actuator when performing maintenance on any of these valves is estimated to take 37 hours4.282407e-4 days <br />0.0103 hours <br />6.117725e-5 weeks <br />1.40785e-5 months <br /> of outage duration for each valve. The estimated radiation exposure for this work is 0.6 rem for each removal / reinstallation.

Failure of a testable check valve to' fully close during testing using the actuator can be evidenced via the associated position indication in the main control room. It is therefore

. possible to obtain a not-fully-closed indication when testing the testable check valve using the actuator. Not obtaining a fully-closed indication upon stroking the valve closed (via the actuator) prompts the initiation of a meintenance request even though the valve would likely be completely capable of performing its intended check function. (To date, each of f; 0-9307200300 930713 PDR ADDCK 05000461 5y .

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the five testable check valves has had at least one maintenance request generated for this type of problem during previous refueling outages.) _ Implementation of the current revision-

< (Revision 2) of ReliefRequest 2014, which requires each applicable testable check valve to be stroke-tested via the associated actuator during cold shutdown, could thus result in the  :

need to perform additional maintenance during the cold shutdown, possibly extending the.  ;

outage. '

In conclusion, IP feels the valves will operate more reliably without the actuatois' ,

and that the benefits in removing the actuators outweigh what is gained by testing it.e '

valves with the actuators during cold shutdown. As previously discussed, the additio tal  :

information provided by this letter should facilitate expeditious review and approval of the '!

revised relief request as proposed for these valves.

Sincerely yours,

/]u /Lt< y 3

  1. /

&Y Richard. F.! Phares ,

Director, Licensing BJP/TBE/ alm cc: NRC Clinton Licensing Project Manager NRC Resident Office Regional Administrator, Region III, USNRC ,

Illinois Department of Nuclear Safety  ;

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