ML19350F007

Updated LER 81-018/03X-1:on 810512,stack Gas Radiation Monitor 1705-18A Was Downscale & Inoperable Following Lightning Strike Near Main Stack.Caused by Voltage Surge Resulting in Preamplifier & Discriminator Circuits Failure

ML19350F007
Person / Time
Site:	Pilgrim
Issue date:	06/16/1981
From:	Mcloughlin M BOSTON EDISON CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML19350F004	List: ML19350F003 ML19350F007
References
LER-81-018-03X, LER-81-18-3X, NUDOCS 8106240038
Download: ML19350F007 (1)

Text

UPDATE REPORT PREVIOUS REPORT DATE 6/10/81 U.S. NUCLEAR REGULATO7.Y COMMISSitN (7 771 'l '~

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7 4 60 61 CoCKET NUM8ER 68 EV ENT OATE EVENT DESCRIPTION AND PROSARLE CONSEQUENCES h10 o ! 21 I on May 12, 1981 at approximately 1940 hours0.0225 days <br />0.539 hours <br />0.00321 weeks <br />7.3817e-4 months <br /> following a lightning hit in the area j i o i 3, [ of Main S tack, the Stack Gas Radiation . Monitor 1705-18A alarmed on panel C903 in l Io64l l the control room. An ' A' priority Maintenance Request Number 81-45-90 was immedi- [ ,

l o i s t I ately issued. Investigation revealed that the monitor was downscale and inoperable. l l o is t i The unit was repaired, fully calibrated utilizing s tation procedures numbers l l0l7i ! 3.M.2.6. 3 and 7.4. 2.4 and re turned to service at approximately 2130 hours0.0247 days <br />0.592 hours <br />0.00352 weeks <br />8.10465e-4 months <br /> on May [

I IoieI l 13, 1981 i a0 .

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_ 21 22 23 24 26 27 23 29 30 3t 32 iK N AC ON O P NT MET MOURS S ei 80R 8. SUP' I E R MANUF C RER I^!@lzl@ IZ l@ IZ l@ 10 l 0l 01 01 IN l@ IN ]@ l43N l@ lGj0l8l0lg 33 34 35 '6 31 40 44 42 de 47 CAUSE DESCRIPTION ANO CORRECTIVE ACTIONS ii j o ; l Investigation by I&C personnel determined that both the pre amplifier and pulse  ;

ii i , , ; height discriminator Circuits had failed apparently due to a voltage surge generated ;

,, , , i j by the lightning s trike. These sub components were replaced in-kind, the system i

,,;3; j recalibrated and returned to service.  ;

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7 4 3 5A  % PCWER CTNER STATUS I C RY OISCOVERY DESCRIPTION li j 51 !F l@ l 0 l 9 l 3l@l N.A. l lAl@l Operational Event l l

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2EL!ASEO OFRELEASE AMOUNT OF ACTIVITY LOCATION OF RELEASE N.A. l l N.A. l Ii Ie 3I 3iZ l @ l Zl@l 7 10 tt 44 45 30 PERSONNEL EXPOSURES  :

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