ML20024A367

LER 83-024/03L-0:on 830514 & 15,RHR Sys Suction Valve Closed,Eliminating Flow in Operating RHR Loop.Caused by Deenergized Vital Instrument Bus 2B & Failure of Comparator 2PC-405A-B,respectively.Comparator replaced.W/830609 Ltr

ML20024A367
Person / Time
Site:	Salem
Issue date:	06/08/1983
From:	Frahm R, Zupko J Public Service Enterprise Group
To:	Allan J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
LER-83-024-03L, LER-83-24-3L, NUDOCS 8306170153
Download: ML20024A367 (4)

Text

- - - - -

P ruo-LICENSEE EVENT REPORT CONTROL SLOCK: l l l l l l (PLEASE PRINT CD TYPE ALL CECulCED INFCCMAT1tN)

?

O 1 8 l5 l JLICEN5EE 9 l s lG CODE ls l 2 l@16 ol ol LICENSE le -l 010l NUMeER0l Ol 0l -l26010l@l 26 4 l TvPE LICENSE 1l 1l l

Jo 1l671l@l CAT se l g, CON'T 7

C 1 8

Nu 40 l015l0lO!Ol3l1l1hl0 St DOCKET NUMBER G8 l5 l1 l4 l8 l3 hl 0l 6l 0l 8l 8l 3l@

99 EVENT DATE 74 76 RE PORT D ATE 80 EVENT DESCRIPTION AND PROBABLE CONSEQUENCES h g l On two separate occasions, on May 14, and May 15, 1983, a Residual Heat Removal (RHR) l o g System suction valve' was observed to have closed, thus eliminating flow in the operatirp p g RHR loop. In each instance the operating pump was stopped, and Action Statement 3.4.1.l4b g g ,3 ; gwas entered. No reduction in Reactor Coolant System boron concentration occurred with g O 6 I an RHR loop out of service. A loop was immediately restored to service. The events  ;

p gconstituted operation in a degraded mode in accordance with Technical Specification l gg 6.9.1.9b.

l E CODE S SC E COMPONENT CODE SUSCODE 5 E 7

O 9 8

lClFJg { g ] Q l7lNlS!T!RlUlh b h d h 9 12 13 18 20 to 11 19

_ SE QUE NTI AL OCCUR R E NCE REPORT REvtSION LER RO EVENT YE AR REPORT NO. CODE TYPE NO.

h ,RE l8l3l (--j 23 l Ol 2l 4l 24 26 y

27 l0 l3 l 2

y 30 b y

_ 21 22 3 31 32 l

AM N ACT ON ON PLANT MET NOUR5 SB i FOR 8. SUPPLE MAN A TURER (H

33_ j g ]34g QQ 36 {36@

l0l0l0l0l 37 40 yg di Wg Wg p p p lL l@

42 43 44 47 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS h g l Investigation in the first case revealed that the No. 2B Vital Instrument Bus had been l g lde-energized for maintenance causing the RHR suction valve to close. In the second l l

, , l case Comparator 2PC-405A-B apparently failed, causing the valve to close. Personnel l lwere counseled concerning the first incident and the comparator was. replaced. l i 4 I I 7 a s so 57 5  % POWE R OTH ER STATUS Dis O RY Dl5COVERY CESCRiPTION l3 dh l0 l0 l0 "lhl" NA l U @l Operator observation l

'c8TiviTY COTTENT AMOUNT OF ACTIVITY LOCATION OF RELE ASE 1 6

.rELE9 W AsE@o NA .0 ,,

Or RELE ASEW@l .

l l NA

.0 l

PERSONNEL EMPOSURES NupeER TYPE DESCRIPTION 1 7 l 0l Ol Ol@Ld@l"

na l

PEnsONNEL es 'dits NUMsER DESCRIPTION 1 H l O! Ol Olhl NA 8306170153 830608 *

!Oss TY7 E Or on oNAct To U DESCRIPTION rACitiTY Q hDRADOCK 05000311 PDR ,

pV' i EIB8 Ld@l 7 9 10 wx 1i\4 50 l

t DE CRIPTION

• G ;$UE[@l x wx I 11illlll111lli 7 8 9 10 68 69 80 &

• NAME OF PREPARER

. ah PHONE:-(609) 935-6000 Ext. 4309 j

rn  ;

) ..

~

8^

O PSEG s

L Public Service Electric and Gas Company P.O. Box E Hancocks Bridge, New Jersey 08038 Salem Generating Station June 9, 1983 Mr. J. Allan Acting Regional Administrator USNRC Region 1 631 Park Avenue King of Prussia, Pennsylvania 19406

Dear Mr. Allan:

f LICENSE NO. DPR-75 DOCKET NO. 50-311 REPORTABLE OCCURRENCE 83-024/03L Pursuant to the requirements of Salem Generating Station Unit No. 2, Technical Specifications, Section 6.9.1.9.b, we are submitting Licensee Event Report for Reportable Occurrence 83-024/03L. This report is required'within thirty (30) days of the occurrence.

Sincerely yours, I

' h J. M. Zupko, Jr.

General Manager -

Salem Operations RF:kls CC: Distribution 1

The Energy People P t

_u

' Report Number: 83-024/03L d' Report Date: 06-08-83 Occurrence Date: 05-14-83 Facility: Salem Generating Station Unit 2 Public Service Electric & Gas Company Hancock's Bridge, New Jersey 08038 IDENTIFICATION OF OCCURRENCE:

Reactor Coolant System - Residual Heat Removal Loops - Loss of Operating Loop.

This report was initiated by Incident Reports83-090 and 83-093 CONDITIONS PRIOR TO OCCURRENCE:

Mode 5 - Rx Power 0 % - Unit Load 0 MWe.

DESCRIPTION OF OCCURRENCE:

On two separate occasions, at 1219 hours0.0141 days <br />0.339 hours <br />0.00202 weeks <br />4.638295e-4 months <br />. May 14, and 1628 hours0.0188 days <br />0.452 hours <br />0.00269 weeks <br />6.19454e-4 months <br />. May 15, 1983, a Residual Heat Removal (RHR) System suction valve was observed to have closed, thus eliminating flow in the operating RHR loop. In both cases, the Control Room Operator stopped the operating RHR pump; due to shutdown maintenance, the Auxiliary Alarm System typewriter was inoperable and therefore no RHR suction valve off-normal alarm was received on either occasion.

Due to the loss of RHR loop flow, in each case, Technical Specification Action Statement 3.4.1.4b was entered. In each instance, the valve was re-opened, flow was restored, and the RHR loop was returned to operation. No reduction in Reactor Coolant System (RCS) boron concentration occurred with an RHR loop out of service.

APPARENT CAUSE OF OCCURRERGE:

Investigation revealed that the first incident was due to a valve closure signal originating from de-energization of the RCS Loop Wide Range Pressure instrument. Power to the instrument was lost when No. 2B Vital Instrument Bus was de-energized and tagged out for maintenance; closure of Valve 2RH1 due to loss of the pressure channel was inadvertently overlooked at the time of the tagout.

In the second instance, the respective vital bus was maintained energized, and investigation revealed no bus transients. Comparator 2PC-405A-B in the RCS loop pressure' instrument was replaced, and a strip chart recorder was connected to monitor the circuit operation.

The recorder revealed no abnormalities; no other problems were observed after replacement of the comparator.

P LER 83-024/03L .

ANALYSIS OF OCCURRENCE:

Operability of the RHR loops is required to provide heat removal capability for removing decay heat. A single loop provides sufficient capability; single failure considerations require that two loops be operable. A single RHR pump also provides adequate flow to ensure mixing, prevent stratification and produce gradual reactivity changes during RCS boron concentration reductions.

As noted, in both instances, RHR flow was immediately~ restored, and no reduction in boron concentration occurred. The events therefore involved no risk to the health or safety of the public. The occurrences constituted operation in a degraded mode permitted by a limiting condition for operation and are reportable in accordance with Technical Specification 6.9.1.9b.

Action Statement 3.4.1.4b requires:

With no RHR loop in operation, suspend all operations involving a reduction in boron concentration of the RCS and immediately initiate corrective action to return the required RHR loop to operation.

CORRECTIVE ACTION:

As noted, in both cases, no operations resulting in a reduction in boron concentration were performed. The Control Roo& Operator reopened the suction valve and restarted a pump to restore an RHR loop to operation. Action Statement 3.4.1.4b was terminated at 1250 hours0.0145 days <br />0.347 hours <br />0.00207 weeks <br />4.75625e-4 months <br />, May 14, and at 1634 hours0.0189 days <br />0.454 hours <br />0.0027 weeks <br />6.21737e-4 months <br />, May 15, 1983, respectively.

In the first instance, personnel involved in the tagout were counseled concerning the need to thoroughly determine the impact of a tagging operation on the plant status. The incident will also be addressed in a weekly operations directive. In the second case, as noted, no problems were observed following replacement of the comparator. No other action was deemed necessary in view of the apparently isolated nature of the problem.

FAILURE DATA:

1- Hagan. Corporation Signal Comparator Module Model 118 Prepared By R. Frahm t e Generdl Manager -

[/ Salem Operations SORC Meeting No.83-077 l

i w.