ML20011E233

LER 89-026-00:on 891228,radiation Monitoring Sys Vent Noble Gas Monitor 2R41A Channel Spiked,Resulting in Containment purge/pressure-vacuum Relief Sys Isolation.Caused by Design/ Equipment Problem.Channel Reset & Guide posted.W/900124 Ltr

ML20011E233
Person / Time
Site:	Salem
Issue date:	01/24/1990
From:	Miller L, Pollack M Public Service Enterprise Group
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-89-026-02, LER-89-26-2, NUDOCS 9002120214
Download: ML20011E233 (4)

Text

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?. .. s O PSEG j Public Service Electric and Gas Company P.O. Box 236 Hancocks Bridge, New Jersey 08038 -

, Salem Generating Station ,

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' January 24,,1990 -

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U..S. Nuclear: Regulatory Commission Document.-Control Desk

~ Washington, DC .

20555

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Dear Sir:

l SALEM GENERATING STATION LICENSE'NO. DPR-75 DOCKET NO. 50-311

-UNIT.NO. 2 LICENSEE EVENT REPORT-89-026-00  ;

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.This Licensee Event-Report is being submitted pursuant to the requirements of the Code of' Federal Regulations 10CFR -c 50.73 (a)'(2) (iv) . This report is required within : thirty (30) days of~~ discovery.

Sincerely yours,

.c >

L. K.-Miller General Manager -

Salem' Operations j i'

MJP:pc

Distribution 9002120214 900124 ADOCK0500g1

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! .er.AC, ,4-, . . . ,~ . .-,.. . , n .i on 12/28/89 at 1750 hours0.0203 days <br />0.486 hours <br />0.00289 weeks <br />6.65875e-4 months <br />, the Radiation Monitoring System (RMS) Plant Vent Noble Gas Monitor, 2R41A, channel spiked resulting in a ,

Containment Purge / Pressure-Vacuum Relief System (CP/P-VRS) isolation signal. The isolation signal had occurred at approximately the same time the 2R41 pump was being restarted after the completion of investigations of a low flow alarm. The root cause of this event can be attributed to a design / equipment problem. The Victoreen RMS equipment has been shown to be susceptible to electrical spikes. As stated previously, the 2R41 pump was being restarted at the time the isolation signal occurred. The 2R41 pump controls are in the same Nuclear Instrumentation Module (NIM) bin as is the 2R41A channel.

Therefore, it is surmised that the pump start signal may have caused the electrical spike. There is no specific troubleshooting procedure for the pump; therefore, no specific requirement to " block" the 2R41A channel response exists. Upon receipt of the ESF signal, the 2R41A channel was reset. This event will be reviewed with applicable Maintenance Department personnel. An " Operating Guide" will be posted to identify that the 2R41A channel alarm response blocking requirements. As indicated in several previous LERs, associated with CP/P-VRS signal actuation, Engineering has investigated the RMS system concerns. Several system design modifications are planned which will eliminate the spurious CP/P-VRS actuation signals. These modifications include installation of a regulated or uninterruptable power supply and eventual upgrade or replacement of the current Victoreen model detector system (s).

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LICENSEE EVENT-REPORT-(LER) TEXT CONTINUATION i S21em_ Generating Station DOCKET NUMBER LER NUMBER PAGE Unit 2- 5000311- 89-026-00 2 of 3

. PLANT AND SYSTEM IDENTIFICATION:

1 Westinghouse ~ bressurized Water Reactor Energy Industry Identification System (EIIS). codes'are identified in the text as lxxl <

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. IDENTIFICATION _ OF_ OCCURRENCE:

Engineered' Safety Feature (ESP) Actuation Signal ~, Containment '

Purge / Pressure-Vacuum Relief isolation, due to a design / equipment problem i'

Event Date: ~12/28/89 Report Date: 1/24/90 This report was initiated by Incident Report No.89-805.

sONDITIONS PRIOR TO OCCURRENCE:

Mode 1 Reactor Power'100% - Unit Load 1160 MWe

_ DESCRIPTION _OF OCCURREN_C_El On December 28, 1989 at 1750 hours0.0203 days <br />0.486 hours <br />0.00289 weeks <br />6.65875e-4 months <br />, the Radiation Monitoring System

'(RMS) IILl Plant Vent Noble Gas Monitor, 2R41A,-channel spiked i resulting in a Containment. Purge / Pressure-Vacuum Relief ~Syctem.

(CP/P-VRS) lBFI isolation signal. The isolation signal had occurred at iapproximately the same time the-2R41 pump was being restarted after the completion of investigations of a low flow alarm._

4PPARENT CAUSELOF OCCURRENCE:

The root cause of this event can be attributed to a design / equipment

problem.as discussed in several prior LERs, ( e .. g . , 311/89-002-00).

The Victoreen RMS equipment has been shown to be susceptible to

-electrical spikes.

As stated.above, the 2R41 pump-was being restarted at the time the isolation. signal occurred. The 2R41 pump controls are in the same Nuclear-Instrumentation Module (NIM) bin as is the 2R41A' channel.

Therefore, it is surmised that the pump start signal may have caused theJelectrical spike. There is no specific troubleshooting procedure l for the pump; therefore,.no specific requirement to " block" the 2R41A channel response exists. The procedure used for conducting investigations of inoperable I&C equipment is IIC-14.1.001, " General

-Troubleshooting Procedure For Installed Plant Equipment".

_ ANALYSIS _ OF OCCURR.EN_ gel Isolation of the CP/P-VRS is part of the design Engineered Safety

' Features (ESFs). It mitigates the release of excessive quantities of radioactive material to the environment after a design base accident.

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, LICENSEE EVENT REPORT (LER) TEXT CONTINUATION V ~~

i

',- r Sr.lem Generating Station DOCKET NUMBER LER NUMBER PAGE Unit 2 5000311 89-026-00 3 of 3 i

[ ANALISIS_QF OCCURRENQE: (cp_nt'd)_ l Y %+ 2R41A channel monitor's the plant vent ef fluent releases f or txtioactive particulates via representative sampling. The ESF r actuation feature of CP/P-VRS isolation, associated with this channel, is of conservative design. It is not taken credit for in p the UFSAR nor is it addressed by the Technical Specifications. The

. channel which is taken. credit for CP/P-VRS isolation is the 2R12A j channel which monitor's Containment noble gas activity. During this event, the ~2R12A monitor. remained operable.

As indicated in the Apparent Cause of Occurrence section, the ';

isolation signal was the result of a design / equipment problem. It was not th* result of high plant vent activity. Thereforo, this event dht nat affect the health or safety of the public. However,  ;

due to the actuation of an ESF system, this event is reportable in )

accorlance with Code of Federal Regulations 10CFR50.73(a) (2) (iv) .

1 g C.OJRECJIVE_ ACTION:

j Upon receipt of the ESF signal, the 2R41A channel was reset.

, This. event will be reviewed with applicable Maintenance Department personnel to explain the relationship between 2R41 pump starts and inadvertent CP/P-VRS actuations.

An " Operating Guide" will be posted to identify that the 2R41A RMS channel alarm response blocking requirements (reference station administrative procedure AP-3, " Document Control Program") when working on the 2R41 pump.

As indicated in prior LERs, associated with CP/P-VRS signal actuation, Engineering has investigated the RMS system concerns.

Several system design modifications are planned which will eliminate spurious CP/P-VRS actuation signals. These design modifications include installation of a regulated or uninterruptable power supply and eventual upgrade or replacement of the current Victoreen model detector system (s). The plans for completion of these modifications ,

are included in the current PSE&G Living Engineering Plan for the RMS System.

General Manager -

C Salem Operations MJP:pc SORC Mtg.90-007 4