ML19256G198

LER 79-113/03L-0:on 791121,hourly Surveillance Requirements Not Performed for 5.5-h While Incore Instrumentation Was Inoperable.Caused by Procedural Deficiency.Equipment Status Board Not Updated.Procedure Pp 1102.02 Revised

ML19256G198
Person / Time
Site:	Davis Besse
Issue date:	12/18/1979
From:	David Brown TOLEDO EDISON CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML19256G196	List: ML19256G195 ML19256G198
References
LER-79-113-03L, LER-79-113-3L, NUDOCS 7912270599
Download: ML19256G198 (2)

Text

U. S. NUCLE AR O . . .

NRC FORM 3CG (7 77)

• LICENSEE EVENT REPORT (PLEASE PRINT OR TYPE ALL REQUIRED INFORMATION)

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[oM 7 8 SOjHT e 6G 61 DOCKET NV.*B E R 63 EVENT DATE 15 REPORT DATE 60 EVENT DESCRIPTION AND PROBABLE CONSEQUENCES h a 2 l Station personnel f ailed to perform the hourly surveillance requirements of Technical l l

o 3 l Specification 4.2.1 for five and one half hours on Noveuber 20, 1979 when the incore o a [ instrumentation was inoperable. The personnel on shift did not realize the incore in-]

o s Istrumentation was inoperable. There was no danger to the health and safety of the l o s Ipublic or station personnel. Axial power imbalance was determined to be well within l acceptable limits when the surveillance testing was resumed. (NP-33-79-131) I g

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OCCURRENCE REPORT REVISION SEQUENTI AL CODE TYPE N O.

REPORT NO.

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i o ]The cause of this incident was a procedural deficiency. The equipment status board li j i j l was not updatec' correct.ly because it did not indicate the incore instrumentation j l was inoperable. Station procedure PP 1102.02 was revised to add nc :es to assure j i 7 ii3 l that inoperability of the incore instrumentation due to exceeding the late date for l

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i 4 UT_5033.01 is logged on the equipment status board.

7 8 3 OTHER STATUS ISCO RY DISCOVERY DESCRtPTION ST S * .P O .'. E R l1 15 l l E lh I ol 6 l 5 lhl NA l (_A jh] Shift Foreman observation l ACTIVITY CO TEN 1 AMOUNT OF ACTIVITY LOCATION or RELE ASE nEleAsEo OF RELEASE lilo: 8LZ_] @ l ZI@l m I Im 60 10 44 45 7 9 T1 PERSONNEL E XPOSURES NUYHER TYPE DESCRIPTION I

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NAME OF PREPARER F

TOLFD0 EDISON COMPANY DAVIS-BESSE NbCLEAR POWER STATION UNIT ONE SUPPLEMENTAL INFORMATION FOR LER NP-33-79-13~2 DATE OF EVENT: November 21, 1979 FACILITY: Davis-Besse Unit 1 IDENTIFICATIGN OF OCCURRENCE: Failure to perform ST 5020.01, " Imbalance, Tilt, and Rod Index Calculations - Group 38 Inoperable" with incorc instrumentation inoperable Conditions Prior to Occurrence: The unit was in Mode 1, with Power (MRT) = 1801, and Load (Gross MWE) = 550.

Description of- Occurrence: On November 20, 1979 at 1821 hours0.0211 days <br />0.506 hours <br />0.00301 weeks <br />6.928905e-4 months <br />, operations personnel began performing ST 5020.01 due to the inoperability of the incore inctrumentation and computer Group 38. At the time, the inoperability of Group 38 was logged on the equipment status board but inoperability of the incore instrumentation was not.

At 0300 hours0.00347 days <br />0.0833 hours <br />4.960317e-4 weeks <br />1.1415e-4 months <br /> on November 21, 1979, computer Group 38 was restored. The Shift Fore-man, thinking that ST 5020.01 was only being done for the previously inoperable Group 38, suspended ST 5020.01. At 0830 hours0.00961 days <br />0.231 hours <br />0.00137 weeks <br />3.15815e-4 months <br /> on November 21, 1979, the Shift Foreman discovered that the incore instrumentation was indeed inoperable and immediately resumed ST 5020.01.

Failure to perform ST 5020.01 with incore instrumentation inoperable violated Tech-nical Speciff'_ation Surveillance Requirement 4.2.1 which states that when the axial power imbalance alarm is inoperable axial power imbalance must be calculated at least once per hour.

Designation of Apparent Cause of Occurrence: The cause of this incident was a pro-cedural deficiency. The equipment status board was not updated correctly because it showed Group 38 as being inoperable but not the incore instrumentation. As a result ST 5020.01 was erroneously suspended when computer group 38 became operable.

Analysis of Occurrence: There was no danger to the health and safety of the public or to station personnel. The parameter which was required to be checked within the five and one half. hours that ST 5020.01 was suspended was axial power imbalance.

This parameter was found to be within acceptable limits when ST 5020.01 was resumed. ,

Corrective Action: At 0830 hours0.00961 days <br />0.231 hours <br />0.00137 weeks <br />3.15815e-4 months <br /> on November 21, 1979 the Shift Foreman upon dis-covering that the incore instrumentation was inoperable immediately resumed ST 5020.01. Station procedure PP 1102.02, " Plant Startup Procedure" was revised to add notes to assure that inoperability of the incore instrumentation due to exceeding the late date for ST 5033.01 is logged on the equipment status board.

Failure Data: There have been no previous similar events.

1644 072 LER #79-113