ML16341G253

Grants Relief Request from Requirement of ASME Section XI, Subsections IWP-3300 & IWP-3500(b) to Annually Measure Bearing Temp of All Pumps in Inservice Testing Programs

ML16341G253
Person / Time
Site:	Diablo Canyon
Issue date:	08/21/1991
From:	Rood H Office of Nuclear Reactor Regulation
To:	Shiffer J PACIFIC GAS & ELECTRIC CO.
References
GL-89-04, GL-89-4, NUDOCS 9109050076
Download: ML16341G253 (8)

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Docket Nos. 50-275 and 50-323 UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555 August 21, 1991 Mr. J.

D. Shiffer Senior Vice President Nuclear Power Generation Pacific Gas and Electric Company 77 Beale Street, Room 1451 San Francisco, Cali for nia 94106

SUBJECT:

RELIEF FROM THE REQUIREMENTS OF THE DIABLO CANYON INSERVICE TESTING (IST)

PROGRAM TO MEASURE PUMP BEARING TEMPERATURE Backcaround By letter dated May 17, 1991, Pacific Gas and Electric Company (PGSE) requested relief from the requirement of ASME Section XI, Subsections IWP-3300 and IWP-3500(b) to annually measure the bearing temperature of all pumps in the IST program.

The request was made pursuant to 10 CFR 50.55a(g) and NRC Generic Letter (GL) 89-04, "Guidance on Developing Acceptable Inservice Testing

( IST) Programs."

PGSE's Basis for Re uestin Relief In lieu of measuring pump bearing temperatures

annually, PGSE proposed to measure bearing vibration on a quarterly basis.

The vibration testing would be conducted in accordance with the requirements and acceptance criteria specified in ASME Operation and Maintenance Pump Standard ASME OM-6.

In support of the request for relief, PGSE stated that it has been demonstrated that pump bearing temperature rise occurs only a short time prior to bearing failure, making it improbab le that annual bearing temperature measurements would effectively identify bearing degradation.

Additionally, PGSE stated that many pumps in the Diablo Canyon IST Program are operated on recirculation flow for the purposes of the annual ASME Section XI test.

Running the,

. cps until stable bearing temperatures are achieved requires excessive pump running time on recirculation flow (approximately 1 to 1.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br />), which has been shown to contribute to pump degradation.

In summary, PGKE stated that measuring pump bearing vibration in accordance with ASME OM-6 will provide a better indication of pump degradation than the presently used combination of ASME Section XI bearing vibration and temperature measurements, and will minimize the potential for pump degradation resulting from operation on recirculation flow.

9109050076,910821 PDR ADOCK'5000275 POR

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Mr. J.

D. Shiffer Pacific Gas and Electric Company Diablo Canyon Evaluation The NRC staff has evaluated PGSE's request for relief and agrees that the temperature at the pump bearings will not increase significantly until immediately before a bearing failure.

Therefore, the likelihood of detecting an impending bearing failure with a single annual bearing temperature measurement is very small.

The staff finds that the quarterly pump vibration measurements provide more information about the degradation of the bearing than the annual bearing temperature measurement.

On this basis the staff finds PGSE's relief request to be acceptable.

Conclusion The NRC staff hereby grants the relief requested by PGSE from the requirement of ASME Section XI, Subsections IWP-3300 and IWP-3500(b) to annually measure the bearing temperature of all pumps in the IST program.

The staff concludes that relief may be granted as requested pursuant to 10 CFR 50.55a(a)(3)(i) because the alternate testing proposed by PGSE provides an acceptable level of quality and safety.

Sincerely, Harry Rood, Senior Project Manager Project Directorate V

Division of Reactor Projects III/IV/V Office of Nuclear Reactor Regulation CC:

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Mr. J.

D. Shiffer Pacific Gas and Electric Company Diablo Canyon CC:

Regional Administrator, Region V

U.S. Nuclear Regulatory Coraoission 1450 Maria Lane, Suite 210 Walnut Creek, California 94596 Mr. Peter H. Kaufman Deputy Attorney General State of California 110 West A Street, Suite 700 San Di ego, California 92101 NRC Resident Inspector Diablo Canyon Nuclear Power Plant c/o U.S. Nuclear Regulatory Commission P. 0.

Box 369 Avila Beach, California 93424 Richard F. Locke, Esq.

Pacific Gas 5 Electric Company Post Office Box 7442 San Francisco, California 94120 Mr. John Hickman Senior Health Physicist Environmental Radioactive Mgmt. Unit Environmental Management Branch State Department of Health Services 714 P Street, Room 616 Sacramento, California 95814 Michael M. Strumwasser, Esq.

Special Assistant Attorney General State of California Department of Justice 3580 Wilshire Boulevard, Room 800 Los Angeles, California 90010 Managing Editor The Count Tele ram Tribune 1321 Johnson Avenue P. 0.

Box 112 San Luis Obispo, California 93406 Chairman San Luis Obispo County Board of Supervisors Room 370 County Government Center San Luis Obispo, California 93408 Ms. Sandra A. Silver Mothers for Peace 660 Granite Creek Road Santa Cruz, California 95065 Dr.

R.

B. Ferguson, Energy Chair Sierra Club California 6715 Rocky Canyon

Creston, California 93432 Ms. Nancy Culver 192 Luneta Street San Luis Obispo, California 93401 Ms. Jacquelyn C. Wheeler 3303 Barranca Court San Luis Obispo, California 93401

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Mr. J.

D. Shiffer Pacific Gas and Electric Company August 21, 1991 Diablo Canyon Evaluation The NRC staff has evaluated PGIIE's request for relief and agrees that the temperature at the pump bearings will not increase significantly until immediately before a bearing failure.

Therefore, the likelihood of detecting an impending bearing failure with a single annual bearing temperature measurement is very small.

The staff finds that the quarterly pump vibration measurements provide more information about the degradation of the bearing than the annual bearing temperature measurement.

On this basis the staff finds PGImE's relief request to be acceptable.

Conclusion The NRC staff hereby grants the relief requested by PGIIE from the requirement of ASME Section XI, Subsections IWP-3300 and IWP-3500(b ) to annually measure the bearing temperature of all pumps in the IST program.

The staff concludes that relief may be granted as requested pursuant to 10 CFR 50.55a(a)(3)(i).

because the alternate testing proposed by PGImE provides an acceptable level of quality and safety.

Sincerely, CC:

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