ML20206R389

Special Rept 1-SR-86-021:on 860513 & 0616,Units 1 & 2, Respectively,Experienced Excessive Alarms on Steam Generator Sensors.Caused by Improper Alarm Setpoint Calibr.Work Request Generated to Check Setpoints During Shutdown

ML20206R389
Person / Time
Site:	Palo Verde, 05005298
Issue date:	07/07/1986
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-86-021, 1-SR-86-21, NUDOCS 8607070130
Download: ML20206R389 (2)

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Arizona Nuclear Power Project P.O. BOX 52034 e PHOENIX, ARIZONA 85072-2034 Mr. John B. Martin, Regional Administrator Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission Region V 1450 Maria Iane, Suite 210 Walnut Creek, CA 94596-5368

Subject:

Palo Verde Nuclear Generating Station (PVNGS)

Units 1 and 2 Docket No. STN 50-528 (License NPF-41)

STN 50-529 (License NPF-51)

Special Report SR-86-021 File: 86-020-404

Dear Mr. Martin:

Attached please find a Special Report (1-SR-86-021) prepared and submitted pursuant to Technical Specifications 3.3.3.8 and 6.9.2. This report discusses the loose parts vibration monitoring (LPVM) system being declared inoperable.

If you have any questions, please contact me.

Very truly yours,

, OLLL AL E. E. Van Brunt, Jr.

Executive Vice President Project Director EEVB/PGN/jle Attachment  !

cc: R. P. Zimmerman (all w/a)

A. L. Hon  :

E. A. Licitra f

A. C. Gehr INPO Records Center 8607070130 DR 860707 i ADOCK 05000528 l ,

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PALO VERDE NUCLEAR GENERATING STATICN UNITS 1 AND 2 Loose Parts Vibration Monitoring (LPVM) System Declared Inoperable License Nos. NPF-41, NPF-51 Docket Nos. 50-528, 50-529 Special Report 1-SR-86-071 On May 13, 1986, Palo Verde Unit 1 was in Mode 1 (POWER OPERATION) at 100 percent power, when it was discovered that the Steam Generator 1A (Hot Ieg) sensor (Channel 5) and Steam Generator 2B (Cold Leg) sensor (Channel 8) were experiencing excessive alarms. Additionally, the Upper Vessel B (Stud Bolts) sensor (Channel 2) in Unit 1 is out of service, and was reported in the results of the Ioose Parts Detection Program Report.

On June 16, 1986, Palo Verde Unit 2 was in Mode 1 (POWER OPERATION) at 50 percent power when it was discovered that the Steam Generator 1A (Hot Ieg) sensor (Channel 5) was emitting spurious alarms. In this case, the Channel 6  ;

sensor monitors the same Collection Region and would detect any loose part should Channel 5 fail. Although Unit 2 has not yet reached its 30th day of inoperability, this report addresses both Units.

The cause of the excessive alarms in the Unit 1 sensors is believed to be attributed to improper alarm setpoint calibration for Channels 5 and 8.

Rework for all affected channels ic scheduled to be done during the first refueling outage.

The cause of the spurious alarms in the Unit 2 sensors is attributed to the effect of certain plant equipment in operation. As corrective action, a work request has been generated to check the setpoints for possible recalibration in Unit 2. This action is scheduled for the next plant shutdown due to ALARA considerations, as the recalibration is done inside containment.

Additionally, PAT needs to be completed prior to recalibration, in order to incorporate baseline data.

A special report is required and made pursuant to Palo Verde Unita 1 and 2 Technical Specification 3.3.3.8 Action a.

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