ML20210G550

Supplemental Special Rept 1-SR-85-018:on 850925,condenser Evacuation Sys high-range Monitor (RU-142) Inoperable for More than 72 H.Caused by low-range Monitor Being Declared Inoperable Due to Loss of Stored Data

ML20210G550
Person / Time
Site:	Palo Verde
Issue date:	03/17/1986
From:	Van Brunt E ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR
To:	Martin J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
References
1-SR-85-018, 1-SR-85-18, ANPP-35563-EEVB, NUDOCS 8604020524
Download: ML20210G550 (2)

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3 Arizona Nuclear Power Project P.o box $2034 e PHOENIX. ARIZONA 85072-2034

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March 17,1986 ANPP-35563-EEVB/RAB/98.05 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 (PVNGS)

Unit 1 Supplement to Special Report - Exceeding Action Statement for Operability of the High Range Noble Gas Activity Monitor File: 86-056-026; G.1.01.10

Dear Mr. Martin:

Attached please find Supplement to Special Report (1-SR-85-018) prepared and submitted pursuant to Specification Table 3.3-13 (Radioactive Gaseous Effluent Monitoring Instru-mentation) and Specification 6.9.2 of PVNGS Technical Specifications. The original report discussed exceeding the 72-hour ACTION statement for operability of the High Range Noble Gas Activity Monitor (RU-142).

If you have any questions, please contact me.

Very truly ou s, Cn\ nQ E. E. Van Brunt, Jr.

Executive Vice President Project Director EEVB/RAB/rw Attachments cc: R. P. Zimmerman (all w/a)

A. L. Hon E. A. Licitra A. C. Gehr INP0 Records Center l

8604020524 B60317 7 PDR ADOCK 05000528 g(

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PALO VERDE NUCLEAR GENERATING STATION UNIT 1 Special Report 1-SR-85-018 Docket No. STN 50-528 License No. NPF-41 This-is a supplement to Special Report 1-SR-85-018.

This Special Report is required by Palo Verde Unit 1 Technical Specification Table 3.3-13, ACTION 42-b.

On September 25, 1985, Palo Verde Unit 1 was in Mode 1 at 60 percent reactor power when the Condenser Evacuation System High Range Monitor (RU-142) was inoperable for more than 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. The. monitor was declared inoperable due to the Condenser Evacua-cion Low Range Monitor (RU-141) being declared inoperable due to random loss of stored date.

' The des-ignaof the system is such that, if the low range monitor is inoperable, the high range monitor ~is also inoperable.

RU-142 remained inoperable for greater than 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> due to troubleshooting-on RU-141.

Actions taken for RU-141 in accordance with Technical Specification Table 3.3-13 have determined that-implementation.of ACTION 42(a) for RU-142 has not'.been necessary.

A design change will be implemented to install an isolated grounding system to

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eliminate the noise on the signal ground which is causing the loss of stored data.

The forecast date of implementation for this design change is June 1,1986.

A design change will a.. 's implemented that will allow the high range monitors

'to 'perate o independently of the low range monitors. The forecast date of implementa-tion for this design change is August 1, 1986.

Condenser Evacuation System High Range Monitor RU-142 vas returned to operable status December 9, 1985.

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