ML20062D282

/03L-0 on 781027:test Revealed Trip Setpoint of 26.5 Inches Water on One Vacuum Switch in Vacuum Relief Sys from Pressure Supression Chamber to Rx Bldg.Caused by Instru Drift in a Mercoid Model CP4122 Vacuum Switch

ML20062D282
Person / Time
Site:	Nine Mile Point
Issue date:	11/14/1978
From:	Macvittie D NIAGARA MOHAWK POWER CORP.
To:
Shared Package
ML17053A238	List: ML17053A237 ML17053A239 ML20062D282 ML20062D284
References
LER-78-037-03L, LER-78-37-3L, NUDOCS 7811210283
Download: ML20062D282 (1)

Text

_

LICENSEE EVENT REPORT d, ' s 3 CONTnol BLOCK: l l

l l l l  !

6 lh (tLEASE PRINT OR TYPE ALL REQUIRED INFOKMATIONI ITTil8 I9NI YlLICENSEE 7

Nl MlCODE Pl ll@15l0 14 10 l -l 0 l 0UCENSE l 0 lNuMSER 0 l 0 j - l O l 0 25l@l 254 l 1UCENSE l 1 l 1TYPE l 11@l 40 l

57 CAT 68 l@

CON'T l0liI 7 8

$$$[ ll60 l@l061 l 5 l0 DOCKET l0 l0 NUMBER l 2l 210l@l 68 l 69l 0l 2EVENT l 7lOATE 7 l 8 l@l 74 11 75 1 REPORT l 1l 4DATE l 7 l 880l@

EVENT DESCRIPTION AND PROBABLE CONSEQUENCES h Io i2l l During normal operation, performance of surveillance test N1-ISP-IC68 l i O i 3, i found a trip setpoint of 26.5 inches water on one vacuum switch in the iO pi i vacuum relief system from the pressure suppression chamber to the rx l O i3i i building (68-128). T.S. 3.3.6F requires a setpoint less than or equal l rO rg 1 I to 0.5 pisg (13.85 inches water). This condition resulted in minimal l

l0l7l1 operation of the vacuum relief valve. l i 0181 l I

7 8 9 80 E COE SUSC E COMPONENT CODE SUS ode S E l0l9l 7 8 9 l S l Al@ W@ LE_J@ l I l N l S l T l R l U l@ O@ l Zi @

10 11 12 13 18 19 20

,,,, SEQUENTIAL CCCURRENCE REPORT REVISION LER RO EVENTYEAR R EPORT NO. CODE TYPE N O.

@ ,aEg l217l8l 22 l-l 23 l0l3l7l 24 26 l./l 27 l0 l3 l 28 29 l Ll 30 g

31 l0 l 32 K N ~ACT ON ON PLANT MET HOURS 22 $8 i POR 8. P MAN PAC RER i

l33E lgl34X lg l5Z 3

lg l36Z lg 3l7 0l0l0l 40 l gg di l Y [g 42 l43 Ni l@ lMl213l5l@44 47 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS h ji ,oil The cause of this failure was instrument drift in a Mercoid Model I gi CP4122 vacuum switch. Trip setpoint was reset to 6.4 inches water. i

,,,,,i Surveillance interval for this switch has been shortened to monthly

, ,,,,il until stabilization is achieved or a cause for the large drift is j i

determined. I 7 8 9 80 STA  % POWER OTHER $7ATUS Of RY OfSCOVERY OESCRtPT10N l l1 Is l l E l@ l 0l 9 l 2'*l@l" NA l lBl@l Surveillance Testing l

' ' " '8 8 A!TiviTY ColTEsf

=ELEAsEO OPRELEASE LOCAUCN CP RELEASE @

li Ie l l Z l @' l Zlgl NA AMOUNTOP" ACTIVITY l NA @ l - l PEpsONNEL EXPO: OES Nuv8E R TvPE DEsCRiPTicN@

i t i l 71 l 01010 l@l Zl@l NA .

l PERSONNEL.N2uks NuuSER DEsCRiPnON@

NA li t a 8l 3l 0 l 0 l 0 l@l12 7 11 l

Sa 0' "

• l fvi'E esc %^PTON"'''*@

NA Y 017 21() ^A 7M l l7 i l 91 8 9 1 Z l@l90 l 80 15suEO

• 12 i8 n3 i i nl l@bE3CPIPTICN 7 'O NA i 68 69 I!!iti!ittiill 80 3 NareE Os pAEpAReR D.K. Ma M d e puoNE: MNOUM M*UN

. - . . . _. . . _ .. . . __ .