ML20135B382

Exam of Motor-Operated Valve Failures W/Application to Increasing Surveillance Testing Period at Texas Utilities Co. Comanche Peak,Units 1 & 2

ML20135B382
Person / Time
Site:	Comanche Peak
Issue date:	02/24/1997
From:	OAK RIDGE NATIONAL LABORATORY
To:	NRC
Shared Package
ML20135B349	List: ML20135B346 ML20135B355 ML20135B382 ML20135B423 ML20135B433 ML20135F833
References
NUDOCS 9703030029
Download: ML20135B382 (9)

Text

. [OAKRDGENATIONALLABORATORY

, 86444aE0 SY LOCKMEED 14MmN ENERGY RESEMtCH CORPORATION PHONE:(423) 8744734 1

. .PORDE U.s. DEPMmIENrOF EfERGY FAlt (433) 8764ess

__ anaRurr aope.w,.

o .mnsman l

January 8,1997 l

Jerry E. Jackson U. S. Nuclear Regulatory C==i== ion MS T10 E10 W. sis.km, D.C. 20555

DearMr. Jackson:

As we discussed in the October 8,1996 meeting with NRC personnel, selected es====4e Peak Motor-f0pgEssed Valves (MOVs) listed in Enclosure 3 to TXX-%371 have been reviewed relative to failure history.

remnanche Peak has requested IST extensios from their current code requirementm an interval of 6 years. l In an effort to provide information neede:i to evaluate potential candidate risk based inservice test (RBIST)

MOVs at C=mache Peak for extended IST intervals, Oak Ridge National Laboratory (ORNL) has done a briefreview of the available NPRDS failure records and performance data for the MOVs in question. The results of this review are provided in the attached senmary report.

The summary report provides a review of motor-operated valve failures at Texas Utilities Company Comanche Peak Nuclear Generating Station, units 1 and 2. The time period ' covered is from 1990 (initial criticality for Unit 1) through 1995. Previous analysis of MOV failures has indicated that gate, globe, and butterfly valves comprise the largest fraction of the MOV population. Therefore, the data search was limited to these types ofvalves. The search resulted in the acquisition of 38 failure records. Only 3 of the 38 failures involved valves that were on the Comanche Peak extension request. Since the failure population relative to the extension request was so small, all failure records for this report were retained to provide at least a limited foundation for analysis. ,

The failures were categorized by functional area of the MOV assembly as valve (26%), actuator (61%), or electrical supply (13%). 'Ihe results appear consistent with other failure smdiet for this component type when compared to the rest of the industry in that degraded or improperly set limit and torque switches account for a large fraction of the failures.

! It has been concluded that the data vamind are insufficient to support the extension of the in-service test i interval to 6 years without the inclusion of other information such as frequency of operation, preventive maintenance practices and M!=, and operating environment' Since C=aneb Peak is a relatively young plant, it is possible that degradation due to service wear will not be seen until more time in service has ,

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- %inging eScience to Bife ATTACHMENT 3

%LBA3Mh9- XA . - - -

. . Jerry E. Jackson January 8,1997

. Page 2 We hope this information will be useful to you. Should you have other questions or require additional infonnstion we would be glad to provide further assistance.

Sincerely, a8.?L A. B. Poole ABP:jke Enclosure cc/ene: P. L. Campbell,NRC J. Colaccino, NRC D.F.Cox D. C. Fischer,tStC W. C. Gleaves, NRC

.' T. G. Scarbrough, NRC .

W. E. Vesely, SAIC J. P. Vora, NRC G. H. Weidenhamer,NRC R. H. Wessman, NRC

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