ML20205G526

Special Rept 2-SR-87-002:on 870222,high-range Noble Gas Activity Monitor RU-144 Inoperable for Greater than 72 H. Caused by Maint Due to Chattering Contacts in Low Voltage Power Supply.Low Voltage Power Supply Replaced

ML20205G526
Person / Time
Site:	Palo Verde
Issue date:	03/16/1987
From:	Haynes J ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR
To:	Martin J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
References
192-00164-JGH-T, 192-164-JGH-T, 2-SR-87-002, 2-SR-87-2, NUDOCS 8703310476
Download: ML20205G526 (2)

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- i Arizona Nuclear Power ProjectliAR 20 !.!! D 26 I P.o. box 52034 e PHOENIX, ARIZONA 85072-2034 l 192-00164-JG5/TRS/F3N March 16, 1987 Mr. John B. Martin, Regional Administrator Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission Region V 1450 Maria lane, Suite 210 Walnut Creek, CA 94596-5368

Subject:

Palo-Verde Nuclear Generating Station Unit 2 Docket No. STN 50-529 (License NPF-51)

Special Report 2-SR-87-002 File: 87-020-404

Dear Mr. Martin:

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Attached please find a Special Report 2-SR-87-002 prepared and submitted pursuant to Technical Specifications 3.3.3.1 and 6.9.2. This report discusses a radiation monitoring unit inoperable for greater than 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.

If you have any questions, please contact Tom Bradish, Compliance Supervisor at (602) 932-5300, Ext. 6936.

Very truly yours,

1. ft y J. G. Ilaynes Vice President Nuclear Production JGil/TRB/FSP/cid Attachment cc: 0. M. DeMichele (all w/a)

E. E. Van Brunt, Jr.

R. I' Zimmerman R. C. Sorenson E. A. Licitra A. C. Gehr INIV Records Center t

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O PALO VERDE NUCLEAR GENERATING STATION Radiation Monitor Inoperable for Greater Than 72 Hours License No. NPF-51 Docket No. STN 50-529 Special Report No. 2-SR-87-002 This Special Report is being submitted pursuant to Technical Specification (T.S.)

3.3.3.9 ACTION 42 b and T.S. 6.9.2 to report an event in which a hi range noble gas activity monitor (RU-144) was inoperable for greater than 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. The 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> limit for operability was exceeded at approximately 0245 MST on February 22, 1987.

Pursuant to T.S. 3.3.3.9 ACTION 42 a the Preplanned Alternate Sampling Program was initiated te monitor the plant ventilation system.

At approximately 0245 MST on February 19, 1987, Palo Verde Unit 2 was in Fbde 5 (COLD SHUTDOWN) for a planned Surveillance Outage when RU-144 was taken out of service for maintenance due to chattering contacts in the low voltage power supply.

Troubleshooting conducted under an authorized work document revealed that the low voltage power supply was not performing its intended function. As immediate corrective action, the low voltage power supply was replaced. A root cause of failure request has been initiated and will address the potential of similar cases in other monitors encompassing all three units.

To return RU-144 to service, Quarterly Functional Test (36ST-9SQ04) was successfully performed. The monitor was declared operable at 1330 on February 24, 1987. The monitor was unavailable for 4 days, 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> and 45 minutes.