ML20028G913

LER 90-011-00:on 900830,containment Ventilation Isolation Occurred.Caused by Failure of Random Access Memory (RAM) Circuit Board in Data Processing Module.Failed RAM Board Replaced & Returned to Vendor for analysis.W/900924 Ltr

ML20028G913
Person / Time
Site:	Vogtle
Issue date:	09/24/1990
From:	Hairston W, Odom R GEORGIA POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
ELV-02122, ELV-2122, LER-90-011-02, LER-90-11-2, NUDOCS 9010030060
Download: ML20028G913 (4)

Text

' Geary a Powt'r Company il", 333 Piedmom A*noe '

q Atlanta. Georg a 33338

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+ 431nverness Center Pahay Post Ott.ce Box 1295 Birm:ngham, Alatiama 3!201 Tempwe ?05 Bf>B 5501 September 24, 1990 , ,, y ,y.,,y n y,,, s n,,,,,,

W. G. Ha6rstori, lit scruor Vce Presclert Nuclear Oprations ELV-02122 0612 Docket No. 50-425 U. S. Nuclear Regulatory Commission ATTN: Do:us.;nt Control Desk Washington, D. C. 20555 Gentlemen:

V0GTLE ELECTRIC GENERATING PLANT LICENSEE EVENT REPORT CIRCUIT BOARD FAILURE LEADS TO QNTAINMENT VENTILATION ISOLATION in accordance with 10 CFR 50.73, Georgia Power Company hereby submits the enclosed report related to an event which occurred on August 30, 1990.

Sincerely, itll (b$$

W. G. Hairston, 111 WGH,Ill/NJS/gm

Enclosure:

LER 50-425/1990-011 xc: Georaia Power Company Mr. C. K. McCoy Mr. G. Bockhold, Jr.

Mr. R. M. Odom Mr. P. D. Rushton NORMS U. S. Nuclear Reaulatory Commission Mr. S. D. Ebneter, Regional Administrator Mr. D. S. Hood, Licensing Project Manager, NRR Mr. B. R. Bonser, Senior Resident inspector, Vogtle 9010030060 900924 PDR S

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On 8-30-90, at 1011 CDT, the Reactor Operator (RO) noticed the Intermediate Radiation Level alarm and .Honitor Circuit Trouble alarm being intermittently displayed on the Safety Related Display Console (SRDC) in the control room for Containment Area Radiation Monitor 2RE-0002. At 1012 CDT, a high alarm was also received on an intermittent basis and a Containment Ventilation isolation (CVI) occurred. Train A and Train B equipment actuated as designed. A redundant monitor (2RE-0003) was checked, but it showed only the normal background radiation level. Chemistry personnel reported that the containment radiation level was normal. The 2RE-0002 Data Processing Module (DPM) was taken to the BYPASS position, but alarms continued to occur on the SRDC. The leads which send the CVI actuation signal from 2RE-0002 were lifted. At 1142 CDT, the CVI signal was reset and by 1310 CDT, all valves and dampers affected by the CV1 were restored to their normal status.

Extensive testing of the r.ystem found that a Random Access Memory (RAM) circuit board in the DPM had failed. This failure led to the intermittent alarms and the CVI. The failed RAM board was replaced and will be returned to the vendor for failure nalysis. Any further corrective actions will be based on the results of w e analysis.

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0 l1l1 -- 0 j0 0;2 or 0l 3 snu,u e a m aecn.unaw, A. REQUIREMENT FOR REPORT This report is required per 10 CFR 50.73 (a)(2)(iv), because an unplanned Engineered Safety feature (ESF) actuation occurred when a Containment Ventilation Isolation (CVI) occurred.

B. UNIT STATUS AT TIME OF EVENT At the time of this event, Unit 2 was in Mode 1 (Power Operation) at 55% of rated thermal power. Other than that described herein, there was no inoperable equipment which contributed to the occurrence of this event.

C. DESCRIPTION OF EVENT On 8-30-90, at 1011 COT, the Reactor Operator (RO) noticed the Intermediate Radiation Level alarm atid the Monitor Circuit Trouble alarm being intermittently displayed on the Safety Related Display Console (SRDC) in the control room for Containment Area Radiation Monitor 2RE-0002. At 1012 CDT, a high alarm was also received on an intermittent basis and a CVI occurred.

Train A and Train B equipment actuated as designed. A redundant monitor (2RE-0003) was checked, but it showed only the normal background radiation

. level. Chemistry personnel reported that the containment radiation level '

! was normal. The 2RE-0002 Data Processing Module (DPM) was taken to the l BYPASS position, but alarms continued to occur on the SRDC. The leads which' I send the CVI actuation signal from 2RE-0002 were lifted to prevent further spurious actuations. At 1142 CDT, the CVI signal was reset and by 1310 CDT, all valves and dampers affected by the CVI were restored to their normal status.

I O. CAUSE OF EVENT Extens w e testing of the system found that a Random Access Memory (RAM)

! circuit board in the DPM had experience a failure. This failure led to the intermittent alarms and the CVI.

E. ANALYSIS OF EVENT The appropriate valves and dampers closed upon receipt of the CVI signal, as  !

designed. Unit operators responded to verify the alarm validity and proper l equipment actuation. Additionally, no actual high radiation condition existed. Based on these considerations, there was no adverse effect on l plant safety or the health and safety of the public as a result of this event. This event was not related to reactor power. Therefore, there would have been no further effects had Unit 2 been operating at a higher power level.

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0l0 0l 3 or 0 l3 vut <, . ,% - w.c - mm.m, F. CORRECTIVE ACTIONS

1. The failed RAM board was replaced.

2. The failed RAM board will be returned to the vendor for failure analysis. Any further corrective actions will be based on the results of the analysis.

G. ADDITIONAL INFORMATION

1. Failed Components:

i RAM circuit board manufactured by Westinghouse Electric Corp.

Part #2440838G01

2. Previous Similar Events:

LER 50-424/1987-021-01, dated 4-7-87.

LER 50-425/1989-001, dated 3-13-89.

LER 50-425/1989-028, dated 11-14-89, i

l Although these LER's address ESF actuations due to DPM failures, none l

address failure of a RAM board so that their corrective actions were not applicable to the prevention of the 8-30-90 event.

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3. Energy Industry identification System Code:

l Radiation Monitoring System - IL Containment Isolation Control System - JM l

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