ML20045C014

LER 93-010-00:on 930514,SDC Lost for Approx Three Minutes When One SDC Suction Valve Closed Due to Initiation of Spurious ESF Actuation Signal.Caused by Personnel Error. Procedural Guidance revised.W/930614 Ltr

ML20045C014
Person / Time
Site:	River Bend
Issue date:	06/14/1993
From:	Booker J, Lorfing D GULF STATES UTILITIES CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-93-010, LER-93-10, RBG-38626, NUDOCS 9306210391
Download: ML20045C014 (7)

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GULF STATES UTILITIES COMPANY fWF lt (1[ND ST A7LON PO*iT Of Fif.E BOX 720 $1 Fli ANCISVkLL. LOUILAN A 70775

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June 14,'1993 RBG-38626 File Nos. G9.5, G9.25.1.3 U.S. Nuclear Regulatory Commission Document Control Desk Washington, D.C. 20555 Gentlemen:

River Bend Station - Unit 1 Docket No. 50-458 Please find enclosed Licensee Event Repon No.93-010 for R.iver Bend Station -

Unit 1. This report is submitted pursuant to 10CFR50.73.

Sincerely, 6 ) a) n ~ s

. E. Booker Manager - Safety Assessment and Quality Verification

, River Bend Nuclear Group N 'SDPP JPS/FRC/DC Jt[H/VCC/kym 180i;aD I

9306210391 930614 f 'd PDR ADOCK 05000458 S PDR n

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cc: U.S. Nuclear Regulatory Commission 611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011 NRC Resident Inspector P.O. Box 1051 St. Francisville, LA 70775 INPO Records Center 700 Galleria Parkway Atlanta, GA 30339-5957 Mr. C.R. Oberg Public Utility Commission of Texas 7800 Shoal Creek Blvd., Suite 400 Nonh Austin, TX 78757 Depanment of Environmental Quality Radiation Protection Division P.O. Box 82135 Baton Rouge, LA 70884-2135 ATrN: Administrator i

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NRC FORM 366 ~

U.S. NUCLEAR REGULATORY COMMISSION [ APPROVED FY oMB NO. 3150-0104

s % EXPIRES 5/31/95 ESTIMATED BunDEN PER AFLPONOC TO COMPLY W7TH THS INF 3RMA TKW COLLECTION NEQUE ST: 50.0 HRS. FORWARD LICENSEE EVENT REPORT (LER) ccMMum ewoNG sVRotN esT,vATe TO THE ,NronMATiON AND RE COHDS MA?.AGCM[ NT BRANCH (MNB9 7714), U.S NUCLEAR Hr GULATOHY COVMGSON. Af4H)NG7DN. DC 20S550301 AND TO THE PAPERWORM Rf DUCTION PROJECT (31 %o t 04). OrFICE OF (See reverse for required number of digits / characters for each block) MANAGEMENT AND BUDGLT WASH:NGTON, DC 20S03 ACILITV NAME p) DOCKET NUMBLR (2) PAGE (3)

[_ RIVER BEND STATION 05000 458 10F 4 T"'E (*) LOSS OF SIlUTDOWN COOLING DURING DE-ENERGIZATIOl OF A POWER DISTRIBUTION PANEL

- EVENT DATE (5) LER NUMBER (6 REPORT NUMBER (7) OTHER FACILITIES INVOLVED (8) sEourN w nEWON f ACUM NAML DUC C NUMBLR MoNm na vrAq YEAR MONTH DAY YEAR 05000 FALiuTY NAMia DCKXET NUMBER 05 14 03 93 - 010 -

00 OG 14 93 05000 OPERATING _TjHIS REPORT IS SUDMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR 1: (Check one or more) (11)

MODE (9) 20.402(b) 20 405(c) x 50.73(a)(2)(iv) 73.71(b) ,

POWER 20 405:aH1)(i) 50.36(c)(1) 50.73(a)(2)(v) 73,71 (c)

LEVEL (10) 0 20 405(a)(1)(n) 50 36(c)(2) 50.73(a)(2)(vit) ol HER I 20 405(a)(1)(m) 50.73(a)(2)(i) 50.73(a)(2)(vm)(A) 'W "' A*ad be'ow and m Text, NRC l 20 405(a)(1)Dvl 50.73(a)(2)(H) 50.73(a)(2)(vm)(B) rm w,A; 20 405(a)(11(v) 50 73(a)(2)(m) 50.73(a)(2)(x)

LICENSEE CONTACT FOR THIS LER (12) e,tsu na enoNE Nuvatn unovae A es cow D.N. Lorfing- Supervisor, Nuclear Licensing (504) 381-4157

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COMPLETE ONE LINE FoR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13) cAur_r su w roMPoNrNT WNUF ACTURER CAULE SYSTEV COMP NE.NT M ANUF ACTURE R f D

SUPPLEMENTAL REPORT EXPECTED (14) EXPECTED WH W iLA4 vrs SUBMISSION p p... wew t a rcan wayssnN DATn

,, 08 14 93 DATE (15)

ABSTRACT (Lrmat to 1400 spaces, i e., approximately 15 singie-spaced typewntten lines) (16) i On 05/lF93 with the p!:nt in Oper:Sn 1 Condition 4 (Cold Shutdcwn), shuidown cooling (SDC) was lost for approximately three minutes when one of the SDC suction valves closed. This occurred due to the initiation of a spurious engineered safety feature (ESP) actuation signal during de-energization of a 120 VAC power distribution panel. Therefore, this report is submitted pursuant to 10CFR50.73(b)(2)(iv) as an ESF actuation.  ;

The root cause of this incident was that on-shift management personnel missed the need for compensatory measures when opening breaker #22 to prevent a loss of SDC. Corrective actions include revising procedural guidance to clarify which valve isolates when breaker #22 is opened.

The dumtion of the loss was minimal (3 minutes) and instrumentation indicated no change in reactor coolant temperature.

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REQUIRED NUMBER OF DIGITS / CHARACTERS FOR EACH BLOCK -

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. BLOCK NUMBER OF NUMBER DIGITS / CHARACTERS TITLE '

1 UP TO 46 FACILITY NAME i

2 DOCKET NUMBER 'l 3 IN ADDITION TO 05000 3 VARIES PAGE NUMBER .

4 UP TO 76 TULE 5 EVENT DATE 2 PER BLOCK 7 TOTAL F LER NUMBER 3 FOR SEQUENTIAL NUMBER 2 FOR REVISION NUMBER 7 REPORT DATE 2 PER BLOCK UP TO 18 - FACILITY NAME 8 OTHER FACILITIES INVOLVED 8 TOTAL - DOCKET NUMBER 3 IN ADDITION TO 05000 9 1 OPERATING MODE 10 3 POWER LEVEL ,

1 II REQUIREMENTS OF 10 CFR CHECK BOX THAT APPLIES 12 TO % M NAME LICENSEE CONTACT 14 FOR TELEPHONE CAUSE VARIES 2 FOR SYGJM 13 4 FOR COMPONENT EACH COMPONENT FAILURE  !

4 FOR MANUFACTURER i NPRDS VARIES SUPPLEMENTA.L REPORT EXPECTED CHECK BOX THAT APPUES 15 EFECTED SUBMISSION DATE 2 PER BLOCK

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.NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY oMB NO. 3150-0104 r3 sa EXPIRES 5/31/95 ESTIVATED BJRDEN PER RESPONSE TO COMPLY WTH TH'S E%T'JS* &s'EniEN E'E5bOyOO?

LICENSEE EVENT REPORT (LER) E S A A EMENT B S

H BB7M4 TEXT CONTINUATION ^1RE t c, u s w r , S, THE PAPERWORK REDJCTON PRCLIECT (31S0 c104) OFFCE OF MANAGEMENT AND BJDGET, W ASMiNGTON, DC 20503 FACILITV NAME 0) DOCP ET NUMBE R (2) LER NUMBER (s) PAGE (3)

- bEQUENhAL REV;bCN g

NUMBER NUVBER oF HIVER BEAD STATION 05000 4 5 8 ~ ~

93 010 00 2 4 un ow n uv. . ,w a m .mm eoo,,, amRm,am o n REPORTED CONDITION On 05/14/93 with the plant in Opentional Condition 4 (Cold Shutdown), shutdown cooling (SDC) was lost for approximately thme minutes when one of the SDC suction valves closed. This occurred due to the initiation of a spurious engineered safety feature (ESF) actuation signal during de- ,

energization of a 120 VAC power distribution panel. Therefore, this repon is submitted pursuant to 10CFR50.73(b)(2)(iv) as an ESF actuation.

INVESTIGATION On 05/14/93, preparations were in progress to allow electrical maintenance to repair power line conditioner SCM*XRCl4A1. This power line conditioner supplies panel SCM*PNL01 A. This work was being done under maintenance work order (MWO) R158874. Operations Section Procedure (OSP)-0019, " Electrical Load Lists" (attachment 43 and enclosum 43), was being used to de-energize all loads on SCM*XRCl4A1. When breaker (*BKR*) #22 was opened, an isolation signal was generated that caused valve E12*MOVF008 (*20*) to close. This caused residual heat removal (RHR) pump "A" (*P*) to trip. Control room operators recognized immediately that shutdown cooling had been lost, and corrective actions were initiated. Breaker #22 on SCM*PNLOI A was closed, the isolation signal was reset, E12*MOVF008 was opened and RHR pump "A" was started to re-establish shutdown cooling. The pump trip occurred at 1310 and shutdown cooling was restored at 1313. The total time that shutdown cooling was not in service was three minutes.

Instrumentation in the control room indicated no rise in reactor coolant tempenture during this time period. Abnormal Operating Procedure (AOP)-0051, "Less of Decay Hea: Removal" was used to assist in restoring shutdown cooling and AOP-0003, " Automatic Isolations," was used to restore any other valves that would have closed when breaker #22 was opened. All other valves that would have closed from this ESF signal were already in the closed position due to plant conditions, with the exception of E12*MOVF053A, the shutdown cooling return valve. This valve was opened after RHR pump "A" was staned to re-establish flow to the reactor.

Operations Section Procedure (OSP)-0019 gives directions for compensatory measures to take when de-energizing electrical buses and panels. This procedure provides guidance for SCM*PNLOI A which had been independently reviewed by the Shift Supervisor, Control Operating Foreman and Shift Technical Advisor. All three individuals did not recognize the fact that measures were needed to prevent a loss of3hutdown cooling when opening breaker #22. Once shutdown cooling had been re-established, steps were taken to prevent isolation of the Division I shutdown cooling valves so that shutdown cooling would not be lost again. The de-energization of SCM*PNL0l A was then NRC FORM 366A (S Bh

D NRC FORM 366A u.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB No. 315(H)104 is et EXPIRES 5/31/95 (STtMATED BVRDFN PER RESPONSE TO COMPLY WlTH TH'S LICENSEE EVENT REPORT (LER) EMSiE2PRoINERo"ENMTih Eo@iNroa%%

TEXT CONTINUATION Qu"5$S c7v^$7'w2"No"o'"f** 73%,"sy,'"

THE PAPERWORK REDUCTION PROJECT (31504104). OFFICE 05 MANAGEMENT AND BUDGET WASHINGTON, D 20501 P ACILITY NAMf (1) DOCKET NUMBEM (2) LER NUMBER l$) - PAGE (3)

YEAR NUMBEA NUMBER 05000 458 RIVElt BEdD STATION 93 -

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TEK1 (!! most spect sg 99y90. u8t edQ@Ur@ C09tOS Of NRC f O!m XfsA} l17) completed with no other problems.

ROOT CAUSE The root cause of this incident was that on-shift management personnel missed the need for compensatory measums when opening breaker #22 to prevent a loss of SDC. This occurre<l during the reviews of attachment 43 and enclosure 43 to OSP-0019. Contributing factors to this oversight were as follows:

1. The compensatory measures to take for opening breaker #22 were very poorly written and led to improper interpretation of what actions needed to be taken. The recommendations for breaker #22 in enclosure 43 reference another procedure when actuation of components can occur if preventive measures are not taken. Information of this kind for all other breakers on SCM*PNL01 A is listed in enclosure 43.

2. The Shift Supervisor was too involved in the actual performance of this evolution, and therefore unable to maintain proper oversight during the implementation of OSP-0019.

A review of previous LERs revealed that LER 89-012 was similar. In LER 89-012, a loss of -

shutdown cooling occurred while an operator was hanging a clearance tag. The hanging of the cleamnce tag required the opening of breaker #20 on panel ISCM*PNL01B. Prior to the event, the Operator reviewed the power loss effect card. This card revealed that a reactor water cleanup system (RWCU) (*CE*) isolation would occer when the breaker was opened but did not make the Opemtor aware of the isolation of shutdown cooling.

CORRECTIVE ACTION ,

To prevent recurrence of this incident, the following corrective measures will be taken:

1. A change notice will be written for OSP-0019 attachment 43 and enclosure 43 to clearly state what valve will isolate on opening of breaker #22 on SCM*PNLOI A. ,

All needed information will be put in enclosure 43 such that there is no need to l

reference another procedure. Attachment 44 and enclosure 44 to OSP-0019 were also reviewed and the same problems are present for breaker #20 on SCM*PNIAlB. '

Enclosure 44 will also be changed by this change notice.

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l i NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB NO. *150-0104 ,

EXPIRES 5/31/95 ESTWATED BJRDEN PER RESPONSE TO COM5'LY WTH THfS INFORMATION COdICTON REQUEST. 510 HRS. FORWARD COMMEms REaARa,No euRoEN EstuATE TO T-E wo MAroN e

LICENSEE EVENT REPORT (LER) AND P,ECORDS MANAGEMENT BRANCH (MNBS 7714)

TEXT CONTINUATION RcowoRy COMM ssoN wAs-Noyoy, oC m3 oo04. U.S. AN3 NUCLEAR 30 THE PAPERWORK REDUCTON PRNECT (31504104L OFFICE OF MANAGEMEN'T AND BJDGET, WASHtNGTON. DC 20503-DOCKET NUMBER (2) L1R NUMBER (4) PAGE p) 7 ACiuTV NAME (1)

LEQVENTiA 6 REV@ON NoMBER NUMBER 05000 OF RIVER BEND STATION 458 93 -

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2. A memo will be sent to all Shift Supervisors to remind them of the need to maintain proper oversight during evolutions. This memo will also emphasize the need to stop l other evolutions when performing a critical task if this is needed to prevent confusion.

3. This event will be included in the industry events training during mqualification training.

4. GSU will review applicable OSP-0019 guidance to identify additional cases in which l other procedures are referenced when compensatory measures are required. I Following this review, a supplemental report will be submitted by August 14,1993 to i document the findings.

SAFETY ASSESS 51ENT At the time shutdown cooling was lost, the plant had been shutdown since 04/17/93 at 1519 (27 days). The dumtion of the loss was minimal (3 minutes) and instmmentation indicated no change in reactor coolant temperature.

Note: Energy industry identification system codes are indicated in the text as (*XX*).

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