ML19211C766

LER 79-128/03L-0:on 791210,during Emergency Ventilation Sys Test,Charcoal Filter Bank in Unit 1-1 Failed to Meet Efficiency Limit in Modes 1-4.Caused by Leakage Between Filter Plate & Assembly Due to Insufficient Gasket Pressure

ML19211C766
Person / Time
Site:	Davis Besse
Issue date:	01/08/1980
From:	Bernard Thomas TOLEDO EDISON CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML19211C763	List: ML19211C762 ML19211C766
References
LER-79-128-03L, LER-79-128-3L, NUDOCS 8001140462
Download: ML19211C766 (2)

Text

,,o (1 71)

LICENSEE EVENT REPORT CONTnot BLOCx: l l l l_l l (PLEASE PRINT OR TYPE ALL REQUIRED INFOHMATION) lo lil lO ] H j D l B l S l 1 l@l 0l 0l -lLICENSE 0l 0 NVYdLH Nl Pl Fl -l 0] 31GL4l h 2ti 1l 1l 1l 1 @l57 L Al T bdl@

UCt.NSE T v FE JG 7 8 9 LLCCP.SE E CODE I4 M CON'T o i yn]

s l Lj@l 0 l 5 l 0 l- l 0 l 3 l 4 l 6 j@!1 M b3 l 2 ]1 l0 l 7 l 9 !@l 0h l 1REPORT EVENT OATE 14 l 0 l D8ATEl 8 l 0tiJ l@

i 8 L0 t> 1 DOCK E T ?.UMB EM EVENT DESCRIPTION AND FROBABLE CONSEQUENCES h l

O 2 l During the performance of ST 5067.02, Emergency Ventilation System (EVS) 18 Month or l

o 3 l Special Test, the charcoal filter bank in EVS Unit 1-1 failed to meet the efficiency o 4 l11mit as required by T.S. 3/4.6.5.1 while in Modes 1 thru 4. Being in Mode 5 at the J o 5 time of the finding, the station did not enter an action statement. This is being l j

o 6 l reported to document a ec- ponent failure. There was no danger to the health and _

o 7 l safety of the public or station personnel. The redundant EVS Train 1-2 was operable l 0 a had it been required. (NP-33-7 9-149) 7 8 9 COVP. VALVE S Y S TE *.f CAUSE CAUSE CODE SUBCODE COYPONENT CODE SUBCODE SUBCODE COOE O 9 lSlHl@ lE @ l Bl@ l Bl f3 Ll 0] Wl El R]h Id W@ [Z_j @

19 20 8 9 la if 12 7

OCCUR R E r.CE REPORT HEVISION SEQU E N T I AL.

REPORT NO, CODE TYPE NO.

@ gEP, L EP RO EVENT YE AR l 7l 9) [__j l1 24 2 8j

/6 y

27 l0l3l 28 2')

lL l 30 l-l 31 W32

_ 21 21 23 ATT ACHY ENT NPRD-4 PRIVE COMP. COVPCNfvT ACTI% FUTUcE [FFECT S H U T Dr : .' ."J SU FPLI E R MANUFACTUNEH TAKE'. A C i t rA ONPLANT YETHUD HOURS SUBUITTED F OH M :,Utt Zlg [ 0l 0l 0 j@ lA j@ lB 0 l 7 l 5 lg

[B jg]4g JJ J h Jo Zl@ 31 40 l l Yl@

41 42 43 44 4/

CAUSE DESCRIPTION AND CORRECTIVE ACTIONS h i o [The cause of the low filter efficiency was leakage between the filter plate and the I

!ilij jassembly. This leakage was due to insuf ficient pressure applied to the gasket.

g,17llUnder Maintenance Work Order 79-3756, the nuts holding the plate were torqued to i 3 75 in-lbs. The unit then successfully met the requirements of ST 5067.02 on l I

liI41 l December 17, 1979. 80 7 8 9 DISCOV H DISCOVETlY OECCRIPTIqN ST A S %POV.En OTHER STATUS test limit l liIsl W @ l0l_0 0

@l NA l

Bl@lUnabletomeet AC TiviTY COYTENT AMOUNT OF ACTIVITY LOCATION OF RELEASE RELE ASTD OF PELE ASE

_ Q lZ @ y@l NA l l NA 80 l

8 9 10 11 44 45 7

PERSONNEL FRPOSURES NUYBER TYPE DESCRIPTION ~

N^ l lu d' I010l01@lZl@l unSONNEl'ImuL S Nuv.ER DoSCR,PTiON@

l li la l8 1010 l '01@l NA q qc B0 1l/j pl J 9 it i2 7

j{J LOSS OF OR OAVAGE TO FACILITY h TYPE DE SCHIP TION  %./

l i 9 tl 9 W@l 10 NA go 7

2 n istuEl @oYs'CnipIioN NA @ l 68 69 lllll l ll l lj 80 g 7 8 9 10 O 08 419-259-5000, Ext. 235 DVR 79-195' NAME OF PREPARER.

Y

• PHONE:

e-h001140 % { g

. s TOLEDO EDISON COMPANY DAVIS-BESSE UUCLEAR POWER STATION UNIT ONE SUPPLE'4 ENTAL INFORMATION FOR LER MP-33-79-149 DATE OF EVENT: December 10, 1979 FACILITY: Davis-Besse Unit 1 IDENTIFICATION OF OCCURRENCE: Emergency Ventilation System (EVS) 1-1 Charcoal Bank

1. 2 F19-1 C-2 leakage 4

Conditions Prior to Occurrence: The unit was in Mode 5, with Power (MWT) = 0, and Load (Gross MWE) = 0.

Description of Occurrence: While performing ST 5067.02, EVS 18 Month or Special Test, the charcoal filter bank in the EVS Unit 1-1 (F19-1, C2) failed to meet ST 5067.02 Acceptance Criteria 7.1 (i.e., the charcoal bank capable of removing 2L 99% of the halogenated hydrocarbon refrigerant test gas with 8000 cfm + 10% of air flow). Since the station was in Mode 5 at the time of the event, the unit did not enter an action statement. This is being reported as documentation of a component failure.

Designation of Apparent Cause of Occurrence: The cause of the low filter efficiency was leakage located between the filter plate and assembly. Leakage was due to in-sufficient plate / assembly pressure applied to the gaskets which may have been induced by normal vibration.

Analysis of Occurrence: There was no danger to the health and safety of the public or to station personnel. The unit was in Mode 5, the redundant EVS Train 1-2 was operable, and there was no fuel in the spent fuel pool.

Corrective Action: The nuts of the filter cells were torqued under Maintenance Work Order 79-3756 on December 17, 1979. This provided the necessary seal. On December 17, 1979, ST 5067.02 was performed successfully. A procedure change will be made to prevent similar occurrences by requiring that the nuts to the filter cells be torqued to 75 in-lbs and a light source leak test be performed following the removal and re-assembly of the filter. This ST 5067.02, EVS 18 Month or Special Test, is always used following any EVS work to ensure operability af ter maintenance.

Failure Data: There have been no previous similar reportable occurrences.

LER #79-128 '. ,2 6 1740

%