ML20212D352

Special Rept 2-SR-87-001:on 870123,preplanned Alternate Sampling Program Initiated to Monitor Plant Ventilation Sys After Radiation Monitor Inoperable for 72 H.Cause Under Investigation.Monitor RU-144 Returned to Svc on 870124

ML20212D352
Person / Time
Site:	Palo Verde
Issue date:	02/13/1987
From:	Haynes J ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR
To:	Martin J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
References
2-SR-87-001, 2-SR-87-1, ANPP-00148-JGH, ANPP-148-JGH, NUDOCS 8703040100
Download: ML20212D352 (2)

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Arizona Nuclear Power Project P O DON S2034

• PHOENIX, An120NA 85012 2034 ANPP-00148-JGil/TDS/MJC-96.03 February 13. 1987 Mr. John 11. Kirtin. Regionni Administrator Of fice of Inspection and Enforcement U.S. Nuclear Regulatory Commission Region V 1450 Maria Inno. Suite 210 Walnut Creek, CA 94596-5368 Sub, Ject : Palo Verde Nucienr Cencrating Station Unit 2 Docket No. S'IN 50-529 (Licenne NPF-51)

Specint Report 2-SR-87-001 ,

Files H7-020-404

Dear Mr. Kirtin:

Attached plenne find a Specini Report 2-SR-87-001 prepared and submitted pursuant l to Technical Specificationn 3.3.3.1 and 6.9.2. This report discussen n rndintion monitor that Nid Icen 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 quentions plonne contact Tom liradinh, Compilance Supervinor at (602) 932-5300, Ext. 6936.

Very trul yourn, h ~6t AL/w J. C. Ila nen Vice Frentdent l Nuctent Produc t ion

,K;ll/TDS/MJC/c td Atinchment cri 0. M. IhMichele (all w/n)

E. I:. Van brunt, Jr.

R. P. Zimmorman H. C. Sorenson I

1. A. Licit ra l A. C. Gehr INIU Recorda Center l

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O PAID VERDE NUCLEAR GENERATING STATION Radiation Monitor Inoperable for Greater Than 72 Ilours ,

License No. NPF-51 Docket No. SfN 50-529 Special Report No. 2-SR-87-001 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 ranse noble gas activity monitor (RU-144) was inoperabic 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 0307 MST on January 23, 1987. Pursuant to T.S. 3.3.3.9 ACTION 42 a the Preplanned Alternate Sampling Program wns initiated to monitor the plant ventilation system.

2 At approximately 0307 MST on January 20, 1987, Palo Verde Unit 2 was in Mode 5 (COLD SHUTDOWN) for a planned Surveillance Outage when RU-144 was taken out of service to allow the implementation of Plant Change Package (l'CP) 85-02-SQ-041-00. This ITP was being implemented to provide Class 1E back up power to RU-144 from the "B" train emergency diesel generator. Modifications to RU-144 were completed at cpproximately 1500 on January 22, 1987. To return RU-144 to service, 36ST-92ZO4 (Radiation Monitoring Quarterly Functional Test) was initiated. During the performance of the functional test, the skid mounted indication and control unit malfunctioned.

Troubleshooting conducted under an authorized work document revealed that the communications interface board had shorted to the mounting hardware and was causing the skid mounted indication and control unit to malfunction. Normal vibration of ,

the skid mounted pump and motor caused the steel washers to rub through the conformal l coating on the communications interface board. This coating is a protective covering l that is used to prevent corrosion of the components on the circuit board. When the

! cteel washers used to mount the circuit board made contact with an electrical trace, o short circuit resulted in the communications interface board. This short circuit I was the cause of the akid mounted indication and control unit malfunction. To prevent

! recurrence, the steel washers were rep 1ticed with nylon washers. A root cause of l failure request has been initiated and will address the potentint of similar cases

! in other monitors encompassing all three units. Troubleshooting also, revealed that several display board Light Emmiting Diodes (LED) had burned out. The display board was replaced.

To return RU-144 to nervice, 36ST-9SQ04 was successfully performed. The monitor was decinred operable nt 2225 on January 24, 1987. The monitoi was unavailabic for 4 days 19 hours2.199074e-4 days <br />0.00528 hours <br />3.141534e-5 weeks <br />7.2295e-6 months <br /> and 18 minutes.

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