ML18095A567

LER 90-034-00:on 901005,containment purge/pressure-vacuum Relief Sys Isolation Signal Actuated as Result of Channel Spike on Radiation Monitoring sys.W/901105 Ltr

ML18095A567
Person / Time
Site:	Salem
Issue date:	11/05/1990
From:	Labruna S, Pollack M Public Service Enterprise Group
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-90-034-01, LER-90-34-1, NUDOCS 9011080208
Download: ML18095A567 (5)

Text

Public Service Electric and Gas Company P.O. Box 236 Hancocks Bridge, New Jersey 08038 Salem Generating Station U. S. Nuclear Regulatory Commission Document Control Desk Washington, DC 20555

Dear Sir:

SALEM GENERATING STATION LICENSE NO. DPR-70 DOCKET NO. 50-272 UNIT NO. 1 LICENSEE EVENT REPORT 90-034-00 November 5, 1990 This Licensee Event Report is being submitted pursuant to the requirements of the Code of Federal Regulations lOCFR 50.73(a) (2) (iv). This report is required within thirty (30) days of discovery.

MJP:pc Distribution 9011080208 901105 PDR ADOCK 05000272 S PDC The Energy People Sincerely yours, S. LaBruna General Manager -Salem Operations r£2..z.. 95-2189 12-89 NllC,_., .. (11-831 U.1, NUCLEAll llEGULATOllV COMMmlOlll APf'fl!OVED 0Me NO.

IM LICENSEE EVENT REPORT ILERI EXPIRH: 113111& l'ACILITV NAME 111 Sa1em Generatinq Station -Unit 1 I DOCKET NUMeEll 121 I r"u* 1:11 0 I 5 I 0 I 0 I 0 I 2, 7 , 2 1 I OF 0 I 4 TITLE 141 ESP -Cont. Venti1ation Iso1ation:

1R11A RMS Channe1 Spikes EVENT DATE 1111 REPORT DATE 171 OTHEll FACILITIEI INVOLVED Ill MONTH L 1 r MONTH DAV VEAR FACILITY NAMES DOCKET NUMBER(SI l I a al s 9 o 9 I r -o 13 I 4 -o lo 1I1 o I s 9 lo Ol'ERATING MODE (II THll REPORT II IUIMITTED l'UAtUANT TO THE REOUIREMENTI OF 10 CFll §: (Ch<<:lt OH or,,,_ of tlN followtn1J 1111 II. 2G.402(bl

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• 7!;71lol ..__ .... OTHER (Sp<<:lfy In Abllnct Hlow ond In ToJ1t, NRC Form 366A} COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIHD IN THll REPOllT 1131 CAUSE SYSTEM COMPONENT I I I I I I I I TURER I I I I I I IUl'PLEMENTAL REPORT EXPECTED 1141 IXl YES f/f yoo, -pin. EXPECTED SU6MISS/ON DATEJ MSTRACT 11.Jmlr ID 1400 -** l.o.. opproJ1lmotely flft#n ling/*-* rypowr/rten

/inmJ 1111 SYSTEM COMPONENT I I I I I I I I MANUFAC-TUR ER I I I I I I EXPECTED MONTH DAY SUBM1$SION DATE 1151 0 11 3 µ. 911 On 10/5/90, a Containment Purge/Pressure-Vacuum Relief System (CP/P-VRS) isolation signal actuated as a result of a channel spike on the Radiation Monitoring System (RMS) Containment Particulate Radiation Monitor, lRllA. Subsequently, Tech. Spec. 3.4.6.1 Action Statement was entered. The isolation valves were closed at the time of this signal; they did not change position.

On 10/6/90, upon completion of a successful channel calibration, the channel was* declared operable and Technical Specification 3.4.6.1 Action Statement was exited. On 11/1/90, another lRllA channel spike occurred resulting in actuation of a CP/P-VRS signal. A Containment pressure relief was in progress at the time of this event. The associated valves closed in response to the isolation signal. Tech. Spec. 3.4.6.1 Action Statement was again entered. The root cause of the two (2) lRllA channel spikes has not yet been identified.

Investigative troubleshooting is continuing,;

A historical review of prior lRllA channel failures was conducted.

The channel has been subject to spikes (approximately once or twice a year). The corrective actions for the prior events included contact cleaning and connector adjustment.

No failed component was identified for several of the prior events. A previous RMS historical review was conducted (reference LER 311/90-031-00) . A concern with LFE Analog Ratemeters models AR-2 and AR-2S power s*upply circuit filtering capacitors was identified.

Subsequently, these capacitors have been scheduled to be replaced for the subject RMS channels.

Investigation to determine if these lRllA cihannel*spikes related to a capacitor problem is on-going.

NRC Form311 19-831 LICENSEE EVENT REPORT (LER) TEXT CONTINUATION Salem Generating Station Unit 1 DOCKET NUMBER .5000272 PLANT AND SYSTEM IDENTIFICATION:

Westinghouse

-Pressurized Water Reactor LER NUMBER 90-034-00 PAGE 2 of 4 Energy Industry Identification System (EIIS) codes are identified in the text as {xxJ IDENTIFICATION OF OCCURRENCE:

Engineered Safety Feature Actuation

-Containment Ventilation Isolation; channel spikes on the lRllA Radiation Monitoring System channel Event Dates: 10/05/90 and 11/01/90 Report Date: 11/01/90 This report was initiated by Incident Repott No.90-754. CONDITIONS PRIOR TO OCCURRENCE:

Mode 1 Reactor Power 100% -Unit Load 1148 MWe DESCRIPTION OF OCCURRENCE:'

On October 5, 1990 at 1306 hours0.0151 days <br />0.363 hours <br />0.00216 weeks <br />4.96933e-4 months <br />, a Containment Purge/Pressure-Vacuum Relief System (CP/P-VRS) isolation signal actuated as a result of a channel spike on the Radiation Monitoring System (RMS) {ILJ Containment Particulate Radiation Monitor, lRllA. Subsequently, Technical Specification 3.4.6.l Action Statement was entered. The isolation valves were closed at the time of this signal; they did not change position as a result of the. isolation signal. On October 6, 1990 at 2205 hours0.0255 days <br />0.613 hours <br />0.00365 weeks <br />8.390025e-4 months <br />, upon completion of a successful channel calibration, the channel was declared operable and Technical Specification 3.4.6.1 Action Statement was exited. On November 1, 1990 at 1845 hours0.0214 days <br />0.513 hours <br />0.00305 weeks <br />7.020225e-4 months <br />, another lRllA channel spike occurred resulting in actuation of a CP/P-VRS signal. A Containment pressure relief was in progress at the time of this event. The associated valves closed, as designed, in response to the isolation signal. Technical Specification 3.4.6.1 Action Statement was subsequently entered. Technical Specification 3.4.6.1 states: "The following Reactor Coolant System leakage detection systems shall be OPERABLE:

a. The containment atmosphere particulate radioactivity monitoring system, b. The containment pocket sump level monitoring system, and

• LICENSEE EVENT REPORT (LER) TEXT CONTINUATION Salem Generating Station Unit 1 DOCKET NUMBER 5000272 DESCRIPTION OF OCCURRENCE: (cont'd) LER NUMBER 90-034-00 PAGE 3 of 4 c. Either the containment fan cooler condensate flow rate or the containment atmosphere gaseous radioactivity monitoring system."*

Technical Specification 3.4.6.1 Action Statement states: "With only two of the above required leakage detection systems OPERABLE, operation may continue for-up*--to 30 days provided grab samples of the containment atmosphere are obtained and analyzed at least once per 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> when the gaseous and/or particulate radioactivity monitoring system is inoperable; otherwise, be in at least HOT STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />." The CP/P-VRS is considered an Engineered Safety System (ESF). Subsequently, on October 5, 1990 at 1323 hours0.0153 days <br />0.368 hours <br />0.00219 weeks <br />5.034015e-4 months <br /> and November 1, 1990 at 2021 hours0.0234 days <br />0.561 hours <br />0.00334 weeks <br />7.689905e-4 months <br /> (respectively) , the Nuclear Regulatory Commission was notified of the automatic actuation signal for CP/P-VRS isolation in accordance with Code of Federal Regulations lOCFR 50.72(b) (2) (ii). APPARENT CAUSE OF OCCURRENCE:

The cause of the first lRllA channel spike could not be identified.

Prior to declaring the lRllA channel operable (on October 6, 1990}, troubleshooting failed to identify any specific equipment concern(s).

This troubleshooting included a visual inspection of the channel electrical components and a channel calibration (which was successfully completed).

On November 1, 1990 a second channel spike, resulting in an ESF signal, occurred.

A cause for this channel spike has also not yet been identified.

However, extensive troubleshooting and inspections are continuing.

ANALYSIS OF OCCURRENCE:

The lRllA, Containment Particulate Monitor, (a NaI scintillation type detector, model LFE MD5B) monitors the air particulate gamma radioactivity in the Containment atmosphere.

It is used in the identification of Reactor Coolant System (ABI leakage in conjunction with the containment pocket sump level monitoring system, the containment fan cooler condensate flow rate monitors, and the containment atmosphere gaseous radioactivity (1Rl2A) RMS channel. An alarm signal will cause the automatic isolation of the CP/P-VRS.

Air samples are pulled directly from the Containment atmosphere through a filter paper which continuously moves past the lRllA scintillation detector.

After the air sample passes through the filter paper, it passes through a charcoal cartridge (monitored by the 1R12B monitor) and is then mixed into a fixed shielded volume where it is viewed by the 1R12A noble gas monitor. The air sample is then returned to the Containment.

• e . LICENSEE EVENT REPORT (LER} TEXT CONTINUATION Salem Generating Station Unit 1 ANALYSIS OF OCCURRENCE:

DOCKET NUMBER 5000272 (cont'd) LER NUMBER 90-034-00 PAGE 4 of 4 Several area radiation monitors, in addition to the 1R12A monitor, are used to corroborate the lRllA channel's indications.

The corroborating area radiation monitors do not have isolation capabilities.

They only have alarm capability.

The 1R41A Plant Vent Particulate monitor also corroborates the lRllA channel indications during Containment purge or pressure-vacuum relief operations.

It also has the capability of automatic isolation of the CP/P-VRS.

During the inoperable period for the lRllA channel, Containment pressure relief was conducted.

The 1R41A channel remained operable during the pressure relief. During either lRllA channel spike, RCS leakage within Containment did not increase.

The corroborating RMS channels did not indicate any increase in Containment airborne activity.

At the time of the second lRllA channel spike, a Containment pressure relief was in progress (via the Plant Vent) . The Plant Vent RMS channels did not identify any significant activity increase.

Therefore, these events did not affect the health or safety of the public. However, due to the automatic actuation signal of an ESF system, they are reportable in accordance with Code of Federal Regulations lOCFR 50.73(a) (2) (iv). An historical review of prior lRllA channel failures was ccilducted.

The channel has been subject to spikes (approximately once or twice a year}. The corrective actions for the prior events included contact cleaning and connector adjustment.

No specific failed component was identified for several of the prior events. CORRECTIVE ACTION: A previous RMS generic historical review was conducted (reference LER 311/90-031-00}

of the RMS ESF related channels.

A concern with LFE Analog Ratemeters models AR-2 and AR-2S power supply circuit filtering capacitors was identified.

Subsequently, these capacitors have been scheduled to be replaced for the subject RMS channels.

The lRllA channel uses the model AR-2 ratemeter.

Investigation to determine if these lRllA channel spikes are related to a capacitor problem is on-going.

As stated in the Apparent Cause of Occurrence Section, extensive lRllA channel troubleshooting and inspections are continuing.

Upon completion of troubleshooting and inspection, a supplemental" report to this LER will be issued. MJP:pc SORC Mtg.90-152 General Manager -Salem Operations