ML19332E799

LER 89-029-00:on 891105,heater Drain Tank High Level Dump Valve 2LV-4333 Isolated from Heater Drain Tank,Causing Steam & Water to Escape from Packing & Reactor Trip.Caused by Failure to Maintain Steam Generator level.W/891204 Ltr

ML19332E799
Person / Time
Site:	Vogtle
Issue date:	12/04/1989
From:	Hairston W, Odom R GEORGIA POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
ELV-01109, ELV-1109, LER-89-029, LER-89-29, NUDOCS 8912120165
Download: ML19332E799 (5)

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, , Giorg;a Power Corspany ..

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. , , 333 Piedmont Avenue - j)

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Atlanta,Gec<ga 30300 >

i A .': Teephone 404 L26 3195 1

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0'  ? . .. / Mabng Address . j

- 40!nverness Conter Patkway-

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Post Oece Box 1295 Birmingham _ Aiatama 35201 Telmhone 205 BGB 5581 Decemb'er 4, 1989 """#""'""**"" j

~ W. G. Hairston, til

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n e- Senior Vice President J

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Nuclear Operatons l

'ELV-01109. l 0135 ]

Docket No. 50-425 i t  ;

U.'S. Nuclear Regulatory Commission -

. ATTN: Document Control' Desk

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Washington, D. C. 20555 Gentlemen:-

V0GTLE ELECTRIC GENERATING PLANT 1

LICENSEE EVENT REPORT SPURIOUS VALVE OPERATION LEADS TO MANUAL REACTOR TRIP j l

In accordance with 10 CFR 50.73, Georgia Power Company hereby submits the enclosed report related to ~an event which occurred on November 5,1989.

Sincerely, M..,8./d' '

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l W. G. Hairston, III WGH,III/NJS/gm

Enclosure:

LER 50-425/1989-029

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xc: Georaia Power Company

'Mr. C. K. McCoy.

Mr. G. Bockhold, Jr.

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Mr. R. M. Odom Mr. P. D. Rushton NORMS l

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U. S. Nuclear Reaulatory Commissign Mr. S. D. Ebneter, Regional Administrator l^ Mr. J. B. Hopkins, Licensing Project Manager, NRR Mr. J. F. Rogge, Senior Resident Inspector, Vogtle l.

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F ACILITY NAME DI DOCKET NUMBER til PAGE (31

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SPURIOUS VALVE OPERATION LEA)S TO MANUAL REACTOR TRIP EVENT DATE (St LER NUMSER tel SEPORT DATE 171 OTHER f ACILITIES INVOLVED tel i >

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On 11-5-89, plant personnel were returning a Heater Drain Tank High Level Dump Valve, 2LV-4333, to service following replacement of valve packing and gaskets.

The valve was isolated from the Heater Drain Tank and operators noticed it indicated 30% open. To check operability, the operators isolated the air line to the valve, whereupon it went full open, as expected. Attributing the 30%

opening to a valid demand signal, operators began to open the valves which had isolated 2LV-4333. At this point, the operators noticed steam and water coming

.from the packing.

The 30% open valve caused the heater drain tank to dump to the main condenser.

This resulted in low main feedwater pump suction pressure which caused the pump to trip. In addition, the standby condensate-pump failed to start on low feedwater pump suction pressure. The reduced feedwater flow resulted in a rapid decrease in steam generator water levels. Anticipating an automatic reactor trip, control room operators initiated a manual reactor trip with steam generator levels at 19% (narrow range indicator) at 1223 CST.

Valve 2LV-4333 moved to the 30% open position due to a defective o-ring (which was replaced) in the valve actuator. The standby condensate pump failure to start was due to its breaker being improperly racked in. The breaker was racked in properly and the pump tested successfully.

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U.S. NUCLEC/4 K12VLATD^W COMM40810N

[ $ ' LICENSEE EVENT REPORT (LER) TEXT CONTINUATION henovio out wo. sino-owa -

EXPlR[$: $131/0B F AC& Lily NAMt (11 DOCKET NUMetR G4 LER NUMSER tel PAGE (3)

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VEGP.- UNIT.2 o p to lo lo l4 l 2l5 49 -

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A. REQUIREMENT FOR REPORT j

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, This report is required per 10 CFR 50.73(a)(2)(iv) because an unplanned.

actuation of the Reactor Protection System occurred.

B. UNIT STATUS AT TIME OF EVENT At the, time of this event, Unit 2 was operating in Mode 1 (Power Operation)  !

at 100% rated thermal )ower. Other than that described herein, there was no  :

inoperable equipment w11ch contributed to the occurrence of this event.  !

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'C.- DESCRIPTION OF EVENT j On 11-5-89, plant personnel were adjusting the Steam Generator Blowdown (SGBD) condensate cooling water return flow to the heater drain tanks.  ;

Additionally, plant equipment operators (PE0's) were returning to service

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the Train A Heater Drain Tank High Level Dump Valve, 2LV-4333, following replacement of the valve packing and gaskets. Prior to opening the valves isolating 2LV-4333, the PE0's noticed that 2LV-4333 was indicating 30% open.

To' check operability, they. isolated the air supply line to the valve,  !

.whereupon-it went full open, as expected. They attributed the 30% opening .i L ~ to a valid demand signal and-then proceeded to re-open the air supply line  !

and open the manual isolation valves which had isolated 2LV-4333 during the I

maintenance work. At this point, they noticed steam and water coming from  ;

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the 2LV-4333 packing. Opening of the isolation valves was stopped while the 1 PE0's sought further direction before continuing the process. j With 2LV-4333 30% open, the Heder Drain Tank began dumping to the main  ;

condenser. This caused the heater drain pump to isolate on drain tank low j L level which resulted in a low suction pressure alarm for both the main  :

. feedwater pumps. As the suction pressure dropped, the standby condensate L pump received a signal to automatically start but failed to do so. The L Balance-of-Plant (B0P) operator attempted to manually start the standby ,

condensate pump with no success. The B0P operator began a power reduction to avoid a main feedwater pump trip, which subsequently occurred due to the low suction pressure. The decrease in feedwater flow and the resultant 3 decrease in steam generator (SG) water levels (to 19% narrow-range) led the Reactor Operator (RO) to manually trip the reactor at 1223 CST and a normal reactor trip ensued. Control rods inserted, the Main Feedwater System isolated and the Auxiliary Feedwater System actuated as designed. Control room operators responded to maintain SG water levels and the unit transitioned to normal operation in Mode 3 at 1240 CST.

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D. CAUSE OF EVENT ,

The dired cause of the reactor trip was the inability of the Control Room Operators to maintain SG water levels. Several factors contributed to this g - condition:

1. Valve 2LV-4333 moved _ to the 30% open position instead of remaining closed due to a defective o-ring in the valve actuator.

2. The PE0s' failed to restore the initial valve alignment when an unexpected condition occurred (water and steam leaking from the packing of valve 2LV-4333) due to an inadequate pre-job briefing. The PE0's were not explicitly advised by the Shift Supervisor (SS) on how to respond if an abnormality occurred.

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l 3. The PE0's were not in constant communication with the control room to i= advise the BOP operator of the valve problem as it occurred. This led to the assumption that the 30% valve opening was due to a valid demand  !

signal.

4. The cctivity involving the adjustments to SGBD condensate cooling water .

E return flow had improperly taken priority over the control room personnel's monitoring of the PE0's activity.

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c 5. The standby condensate pump's failure to start was due to its breaker-l being improperly racked in when last restored to service.

! 6. Investigators found that a similar level control valve incident occurred L the previous week when restoring the ILV-4334 valve to service in Unit ,

l 1. However, personnel involved in the-11-5-89 event were not aware of

! the previous incident due to inadequate communications between shifts. ,

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E. ANALYSIS OF EVENT Control room operators responded properly to trip the reactor as SG water h levels decreased. Main Feedwater isolated and Auxiliary Feedwater actuated

as designed. No abnormalities were experienced as the trip and the subsequent recovery ensued. Based on these consideration.s, there was no adverse effect on plant safety or the health and safety of the public as a result of this event.

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.F.. CORRECTIVE ACTIONS 1.- The defective o-ring was replaced and plant personnel are -

evaluating the need for o-ring replacement each time packing adjustments / replacements are performed.

2./3./4. The involved SS and PE0's have been counseled regarding the proper  ;

restoration to service of valve 2LV-4333. These cognitive

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.I personnel errors were the result of not adequately following approved administrative procedures and were not the result of any unusual characteristics of the work locations.

y i A memo has been added to the Shift Policy Book discussing the purpose'and content of pre-briefings, the use'of functional tests prior to restoring equipment to service, and the need for adequate  !

communication with the control room during field activities.

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5. The standby condensate pump breaker was properly racked in and ,

tested successfully. The procedure used to restore'the standby  !

l condensate pump to service is being re-evaluated for necessary I

changes. Refresher.. training on properly racking in 13.8 kV breakers will be included in non-licensed operator continuing training for 1990. j

6. Management is stressing the use of operator logs in communicating  !

l abnormal operating experience. 3 l- G. ADDITIONAL INFORMATION i l

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l 1. Failed Components Valve 2LV-4333 actuator o-ring supplied by Fisher Controls Corporation.

l-Part No. 1H849806992 l 2. Previous Similar Events There have been no previous reactor trips initiated by the LV-4333-valves" failure to remain closed.

3. Energy Industry Identification System Code w Main Steam System - SB Main Feedwater System - SJ

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Auxiliary Feedwater System - SA

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Control Rod Drive System - AA

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