ML19254E287

Forwards LERs 79-075/03X-1,79-083/03L-0,79-084/03L-0 & 79-085/03L-0

ML19254E287
Person / Time
Site:	Arkansas Nuclear
Issue date:	10/25/1979
From:	Trimble D ARKANSAS POWER & LIGHT CO.
To:	Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML19254E288	List: 05000368/LER-1979-075-03, /03X-1:on 790822,during Mode 1 Operation,Data Link from Control Element Assembly Cluster to B Core Protection Computer Dropped,Resulting in B Channel Tripping.Caused by Failed Optical Amplifier.Data Link Was Repaired 05000368/LER-1979-083-03, /03L-0:on 790926,during Mode 2 Operation,Rod 46 Dropped Four Times to Lower Electrical Limit.Cause Not Stated.Voltage to CEDM Gripper Coils Was Increased & Rod Exercised Successfully.Control Element Assembly Realigned 05000368/LER-1979-084-03, /03L-0:on 790927,during Mode 2 Operation,Control Element Assembly 46 Dropped to Lower Electrical Limit.Cause Not Stated.Gripper Voltage Was Increased to Facilitate Rod Withdrawal.Rod Was Realigned to Group Average 05000368/LER-1979-085-03, /03L-0:on 790925,during Mode 2 Operation,Refueling Water Tank Boron Concentration Was 1,705 Ppmb.Caused by Calculation Based on Boron Concentration Taken Prior to Sufficient Mixing.Operating Procedures Revised ML19254E287
References
2-109-21, NUDOCS 7910310418
Download: ML19254E287 (1)

Text

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ARKANSAS POWER & LIGHT COMPANY PCST CFFICE BOX 551 UTTLE ROCK. ARKANSAS 72203 (500 371-4000 October 25, 1979 2-109-21 Mr. K. V. Seyfrit, Director Office of Inspection & Enforcement U.S. Nuclear Regulatory Commission Region IV 611 Ryan Plaza Drive, Suite 1000 Arlington, Texas 76011

Subject:

Arkansas Nuclear One - Unit 2 Docket No. 50-368 License No. NPF-6 Licenn e Event Report Nos. 79-075/03X-1; 79-083/03.-0; 79-084/03L-0 and 79-085/03L-0 (File:

2-05D)

Gentlemen:

In accordance with Arkansas Nuclear One - Unit 2 Technical Specification 6.9.1.9b, we have attached the subject reports concerning the tripping of channel "B" of the CPC (LER 79-075/03X-1); the drooping of a CEA to the lower electrical limit (LER 79-083/03L-0 and LER 79-084/03L-0) and low boron concentration in the Refueling Water Tank (LER 79-085/03L-0).

Very truly yours,

/

ca

/e.DavidC.Trimble U

Manager, Licensing DCT: MAS:pw Attachment cc:

Mr. Victor Stello, Jr., Director Mr. Norman M. Haller, Director Office of Inspection & Enforcement Office of Management and Program U.S. Nuclear Regulatory Commission Analysis Washington, D. C.

20555 U.S. Nuclear Regulatory Comm.

Washington, D. C.

20555 Mr. W. D. Johnson U.S. Nuclear Regulatory Commission P.O. Box 2090 Rasse'Iville, Arkansas 72801 7910310 h

}7 4

l97 VEMOER MCOLE SCUTH UTILITIES SYSTEM