05000424/LER-1993-009
| ML20056F722 | |
| Person / Time | |
|---|---|
| Site: | Vogtle  |
| Issue date: | 08/23/1993 |
| From: | Mccoy C, Sheibani M GEORGIA POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| LCV-0122, LCV-122, LER-93-009-01, LER-93-9-1, NUDOCS 9308300305 | |
| Download: ML20056F722 (5) | |
| Event date: | |
|---|---|
| Report date: | |
| 4242093009R00 - NRC Website | |
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. >ew , ,sw August 23, 1993 LCV-0122 Docket No. 50-424 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D. C. 20555 Gentlemen:
VOGTLE ELECTRIC GENERATING PLANT LICENSEE EVENT REPORT REACTOR TRIP DURING MAINTENANCE DUE TO LOW PRESSURIZER PRESSURE SIGNAL In accordance with the requirements of 10 CFR 50.73, Georgia Power Company submits the ,
enclosed report related to an event which occurred on July 28,1993. l Sincerely, C. K. McCoy CKM/NJS
Enclosure:
LER 50-424/1993-009 xc: Georcia Power Company Mr. J. B. Beasiey, Jr.
Mr. M. Sheibani NORMS U. S Nuclear Regulatory Commission l
Mr. S. D. Ebneter, Regiond Administrator Mr. D. S. Hoed, Licensing Project Manager, hMR Mr. B. R. Bonser, Senior Resident Inspector, Vogtle i
9308300305 930823 PDR ADDCK 05000424 f I }
S PDR i A _ _ _ _ _ _ _ _ _ _ _
NRC FORA 366 U.S. NUCLEAvt REGULATORY COMMi&&40N APPkOVED OMB NO 3150 0104 (6.-OG) EKPtRES 4C3fD2 ESTluATED BURDEN PER RESPONSE TO COMPLY WITH THIS '
LICENSEE EVENT REPORT (LER) "E,^Tl*R$$*,E' WET,M E @8TuE E" C D D
AND REPORTS MANAGEMENT BRANCH (P-530). US NUCLEAR REGULATORY COMMISSION. WASHINGTON. DC 20b55, AND TO !
THE PAPERWORM REDUCTION PROJECT (315G0104), OFFICE OF MANAGEMENT AND BUDGET. WASHINGTON.DC 20503 ,
par 4 f3 F ACILITY esAME (1) DOCKET NUMBER (2)
Vogtle Electric Generating Plant - Unit 1 0l5l0l0l0l4l2l4 1 OF 4 ,
Ti1LE 14)
REACTOR TRIP DURING MAINTENANCE DUE TO LOW PRESSURIZER PRESSUR.E SIGNAL EVENT DATE (S) LER NUMBER (E) REPORT DATE(7) OTHER F ActLITIES eNVOLVED (S)
MONTH DAY YEA 44 YEAR ,~ Mgfp i
- yty MONTH DAY YEAR FACluTYNAMEb DO(AET NUMbEk(S) l l l l l l I
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017 2 18 9 3 9 13 0 l019 0 10 Ol8 2l 3 913 l l l l l l l gggggg TMas REPORT 86 $UBMITTED PUR&UANT TO TME REQUIREMENT $ OF 10 CF R ? -(Checa one er more or she fosowrig)(11) 20 eabgc)
MODE (9) ] 20 4021D) bO.7%a)(2)(w) 73 71(b)
POWER 20 435(aK1)C) 50 36(cx1) 50 7*aQM 73 71(c)
~
LEVEL (10) } lQ lQ 20 4054a)(t)(n) 50 36scQ 507Aa)(2)M0 OTHER (Sp.c#y M AtasFacf 6.Ow s _ y 20 Aas(.)nX.o 50 7xapc> Sc 7xaci.m4) .ao M T.,t uRC rum mai
- + : 20 4354aH1)(w) 50 7AaQM 50 7XaQ(w(B)
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20 435taXt)M 50 7%a)(2>0+i) 50 73saQts)
LfCENbEE CONT ACT FOR THi& LER (12) hAME TELEPHONE NUMBER
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Mehdi Sheibani, Nuclear Safety and Compliance 7l016 8 l?.16 l- 131210 l9 CORAPLETE ONE L6NE POR EACM COMPONENT S A4 LURE DESCRsBED IN THiE REPORY (13)
CAUSE SYS'1 EM COMPONE'NT MANUF ACTURER RE E p' CAUSE SYSTEM COMPONENT MANUF ACTURER RE A E JS m
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$UPPLEMENTAL REPORT EXPECTED (14)
SUBMISSeON YES 0Froe comen.no ExJTCTED SUBMISSKWDA7E) f NO DATE (15) l l l wac1 co,e ,- 4.. .n , m, a,.ma.wnr n we)
On July 28,1993, technicians replaced pressurizer pressure transmitter 1PT-457 after it had displayed signs of failure. Following calibration, personnel initiated action to place the new transmitter in senice by opening the transmitter's isolation valve, prior to pressurizing the sensing line and transmitter. This caused the pressure in the sensing line, which is shared with transmitter IPT-458, to drop low enough to trip the IPT-458 bistable for low pressurizer pressure. Because the bistable for IPT-457 was already tripped due to the transmitter being out of senice, the required 2 of 4 logic for a reactor trip now existed and a trip occurred at 2350 EDT. Upon recovery from the reactor trip, normal unit operations resumed in Mode 3 (Hot Standby).
The cause of this event was a ceguitive personnel error on the part of the technicians and their foreman in not returning 1PT-457 to sersice in accordance with procedural requirements. Certain steps in the procedure that would have ensured that the sensing line and transmitter were pressurized were omitted during performance of the evolution. The technicians and foreman involved were disciplined and reminded of the importance of procedural compliance.
1 sekc Fonn 366 (649) I N
NRC M 3HA U.S.NC4. EAR f.XGutOTORY COenMi&S40N APPROVED OMB NO $001D4 ESTBAATED BURDEN PER RESPONSE TO COMPLY WITH THIS g*u" Tag'3 ga@E"gu d ' ^"
LICENSEE EVENT REPORT (LER) a gjJyj gsTHElECO TEXT CONTINUATION g aEPm,T8 y = GEMEM DR w NCH ,9 THE PAPERWORK REDUCTION PROJECT (316G0104), OFFICE OF MANAGEMEW AND BUDGET.WASHNGTON. DC 20503, FACLITY NAME (1) DOCKET NUMBLA (2) LER NUMBER (8) PAGE (3)
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Vogtle Electric Generating Plant - Unit 1 TEXT fr mcre spece se regured, use acasonal ARC hym 366Aa)(1 T) 015l0l0l0l4l214 913 010l9 -
0l0 l2 oF l4 A. REQUIREMENT FOR REPORT j This report is required per 10 CFR 50.73 (a) (2) (iv) because an unplanned actuation of the !
reactor protection system (RPS) occurred. ;
B. UNIT STATUS AT TIhfE OF EVENT I
At the time of this event, Unit I was operating in hiode 1 (Power Operation) at 100 percent 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 July 28,1993, technicians replaced pressurizer pressure transmitter IPT-457 after it had displayed signs of failure. Following calibration, personnel initiated action to place the new !
transmitter in senice by opening the transmitter's isolation valve prior to pressurizing the sensing line and transmitter. This caused the pressure in the sensing line, which is shared with transmitter 1PT-458, to momentarily drop low enough to trip the 1PT-458 bistable for low pressurizer pressure. Because the bistable for IPT-457 was already tripped due to the transmitter being out of senice, the required 2 of 4 logic for a reactor trip now existed and a trip occurred at 2350 EDT. Control room personnel observed expected reactor trip indications with the exceptions of digital rod position indication for control rod hil2, which continued to indicate being fully withdrawn on one of the two channels of rod position instrumentation. Subsequent ;
troubleshooting determined that all rods were inserted. Auxiliary feedwater (AFW) actuated as designed when steam generators reached their low level actuation setpoints. Normal unit operation resumed in hiode 3 (Hot Standby).
D. CAUSE OF EVENT The cause of this event was a cognitive personnel error on the part of Georgia Power Company j technicians and their foreman in not returning IPT-457 to service in accordance with procedural j requirements. Certain steps in the procedure that would have ensured that the sensing line and >
transmitter were pressurized were omitted during performance of the evolution. Contributing factors include:
- 1. The pre-job briefing did not discuss the sensitive nature of working on components that shared sensing lines and did not clearly delineate individual job responsibilities for the different technicians who were performing their tasks in two separate locations (the containment building and the control room).
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YEAR M N,T6AL i! R, Egg Vogtle Electric Generating Plant - Unit 1 TEXT (a mcre spece a esgured, une emmarnet NRC Nrm Jo6A s)(17) 015 l0 l0 l0 l4 l214 9 l3 0 l0 l9 -
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- 2. Technicians in the containment building had the calibration data sheet, but not the appropriate steps of the procedure. The technician in the control room had a copy of the procedure, but did not have step-by-step control of the evolution.
There were no unusual characteristics of the work location which contributed to the occurrence of the personnel error.
A failed encoder circuit card was the cause of the failure of one channel of digital rod position indication for control rod M12.
1 E. ANALYSIS OF EVENT No actual pressurizer low pressure condition existed, and the reactor coolant system (RCS) maintained normal temperature and pressure throughout the event. When the reactor trip ,
t occurred, AFW actuated as designed to provide steam generator water for RCS cooling and !
l control room personnel conservatively responded to the control rod M12 fully withdrawn status as if the rod had actually failed to insert. Based on these considerations, there was no adverse ,
effect on plant safety or on the health and safety of the public as a result of this event.
F. CORRECTIVE ACTIONS
- 1. The technicians and foreman involved have been disciplined and reminded of the importance of procedural compliance. Additionally, the following actions are in progress:
- a. The pre-job briefing checklist will be revised by September 15,1993, regarding work to be performed on sensitive instruments.
- b. Procedure 00054-C, " Rules For Performing Procedures" will be revised by September 15, 1993, to more clearly state when procedures are to be "in hand" and to describe performance of procedures that require coordinated action at numerous locations.
- c. Instruments with shared sensing lines that could cause transients under circumstances similar to this event will be labeled appropriately during the next refueling outage on each .
unit. Likewise, these instruments will be armotated in the work order database by September 15,1993.
l
- d. Appropriate department managers will meet with their employees to discuss procedural compliance expectations by September 11,1993.
I NRC PORM M6A U.&. NUCLEAR CEGuto1DR7 COMMi$blON CPPRCrJED OM6 NO MbQ41Q4 (640) EXPIRES 4/3CW92 i
. ESTIMATED BORDEN PER RESPONSE TO COMPLY WITH THis LICENSEE EVENT REPORT (LER) g"M$LC'"dE oe
" S n
ARD TEXT CONTINUATION AND RENRTS MANAGEMENT BRANCH (P-5R U S. NUCLEAR REGULATORY COMMISSICP4, WASHINGTON. DC 20555, AND TO THE PAPERWORK REDN PRCUECT (31500104), OFFICE OF MANAGEMENT AND BUDGET. WASHINGTON DC 20503 f AceLITY hAME (1) DOCKET NUMBER (2) LER NUMDER (6) PAGE (3) va^R i uthym ,a a,g;g Vogtle Electric Generating Plant - Unit 1 rw a ,,-- . m - we w mAwn 0l5l0l0l0l4l214 9 l3 010l9 -
0l0 l4 oF l4 i
- 2. The failed encoder circuit card in the M12 control rod position indication channel has been -
replaced.
G. ADDITIONALINFORMATION
- 1. Failed Components:
Rod position indication encoder circuit card manufactured by Westinghouse Electric Corporation Part No.1468F3G01 -
- 2. Previous Similar Events:
None '
- 3. Energy Industry Identification System Code:
Reactor Coolant System - AB Control Rod Drive System - AA Auxiliary Feedwater System - BA i i
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