ML20214P014

Special Rept 2-SR-86-028:on 860809,action Statement for Operability of Main Steam Line Effluent Monitor RU-139 A/B Exceeded.Caused by Communication Problem W/Radiation Monitor Minicomputer.Cause Undetermined Due to Random Malfunction

ML20214P014
Person / Time
Site:	Palo Verde
Issue date:	09/04/1986
From:	Haynes J ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR
To:	Martin J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
References
2-SR-86-028, 2-SR-86-28, ANPP-00071-JGH, ANPP-71-JGH, NUDOCS 8609170220
Download: ML20214P014 (2)

Text

, .s Arizona Nuclear Power Project ids S6 p,8 p 0 Cox $2C34 e PuoENIX. ARI2ONA 85012-20M h[ fy I3 September 4, 1986 E6/CN yog ANPP-00071-JGH/TDS/MJC-96.03 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 r

Subject:

Palo Verde Nuclear Generating Station (PVNGS)

Unit 2 Docket No. SIN 50-529 (Licentse NPF-51)

Special Report-2-SR-86-028 File: 86-020-404

Dear Mr. Martin:

Attached please find a Special Report (2-SR-86-023) prepared and sabmitted pursuant to Technical Specifications 3.3 3.1 and 6.9.2. This repcrt discusses a radiation monitor that was not restored to operable status within 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 T. R. Bradish, Coopliance Supervisor at (602)932-5300 Ext. 6936.

Very truly yours, jM.M-J . G. Haynes Vice Prealdent Nuclear Production JGH/MJC/dh Attachment cc: O. M. DeMichele (all w/r)

E. E. Van Brunt, Jr.

R. P. Zimmerman A. L. Hon E. A. Licitra A. C. Genr INP0 Records Cent'sr

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ATTACHMENT TO ANPP 00071

.a PALO VERDE NUCLEAR GENERATING STATION UNIT 2 RADIATION MONITORING UNIT NOT RETURNED TO OPERABLE STATUS WITHIN 72 HOURS Docket No. STN 50-529 License No. NPF-51 Special Report 2-SR-86-028 This Special Report is being submitted pursuant to the requirements of Palo Verde Unit 2 Technical Specifications 3.3.3.1, Action Statement 27 and 6.9.2 to provide information regarding a Radiation Monitoring Unit not restored to operable status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.

At approximately 1223 MST on August 9,1986, Palo Verde Unit 2 was in Mode 3 (HOT STANDBY) when the 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> Action Statement for operability of the Main Steam Line Effluent Monitor (RU-139 A/B) was exceeded. The monitor had been declared inoperable at 1223 on August 6,1986, when the monitor developed a communication problem with the radiation monitoring mini-computer through both ports A and B. A work authorizing document was issued to troubleshoot and either rework or replace the components that caused the communication problem.

The work performed under work order 00169093 determined that a System Board had malfunctioned. The board was replaced and RU-139 A/B was returned to operable status at approximately 0523 on August 20, 1986 following a successful retest of the monitor.

A previous similar event was reported in Special Report 2-SR-86-021. It is now believed that the previous event was caused by a spurious malfunction of the System Board. Previous attempts to determine the cause of the detector failure alarms were unsuccessful due to the random nature of the malfunction.

During the time period RU-139 A/B was inoperable, the preplanned alternate program was in effect. This program is implemented by Emergency Plan Implementing Trocedure 14A (Release Rate Determination).

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