ML19351D656

LER 80-078/03L-0:on 800908,w/unit in Startup Mode,Governor Valve for Steam Driven Auxiliary Feedwater Pump Discovered in Tripped Position.Cause of Overspeed Trip Due to Incorrect Governor Setting.Governor Valve Reset

ML19351D656
Person / Time
Site:	North Anna
Issue date:	10/07/1980
From:	Cartwright W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML19351D655	List: ML19351D652 ML19351D656
References
LER-80-078-03L, LER-80-78-3L, NUDOCS 8010140436
Download: ML19351D656 (3)

Text

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LICENSEE EVENT REPORT CONTROL BLOCK / / / / / / / (1) (PLEASE PRINT OR TYPE ALL REQUIRED INFORMATION)

/0/1/ /V/A/N/A/S/1/ (2) /0/0/-/0/0/0/0/0/-/0/0/ (3) /4/1/1/1/1 (4) / / / (5)

LICENSEE CODE LICENSE NUMBER LICENSE TYPE CAT

/  ! /L/ (6) /0/5/0/0/0/3/3/8/ (7) /0/9/0/8/8/0/ (8) /1/o/o/7 /8/o / (9)

DOCKET NUMBER EVENT DATE REPORT DATE EVENT DESCRIPTION AND PROBABLE CONSEQUENCES (10)

/0/2/ / On September 8,1980 with the unit in startup mode, the governor valve for the /

/0/3/ / steam driven auxiliary feedwater pump was found to be in the tripped condition /

/0/4/ / rendering the pump inoperable contrary to T.S. 3.7.1.2 and reportable by /

/0/5/ / T.S. 6.9.1.9.b. Since the other auxiliary feedwater pumps were operable, the /

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/0/6/ / health and safety of the public were not affected. The incident is not /

/0/7/ / generic. /

/0/8/ / /

SYSTEM CAUSE CAUSE COMP. VALVE CODE CODE SUBCODE COMPONENT CODE SUBCODE SUBCODE

/0/9/ /H/H/ (11) /A/ (12) /X/ (13) /T/U/R/B/I/N/ (14) /Z/ (15) /Z/ (16)

SEQUENTIAL OCCURRENCE REPORT REVISION LER/R0 P1ENT YEAR REPORT NO. CODE TYPE NO.

(17) BEPORT NUMBER /8/0/ /-/ /0/7/8/ /\/ /0/3/ /L/ /0/ /1/

ACTIGN FUTURE EFFECT SHUTDOWN ATTACHMENT NPRD-4 PRIME COMP. COMPONENT TAKEN ACTION ON PLANT METHOD HOURS SUBMITTED FORM SUB. SUPPLIER MANUFACTURER

/E/ (18) /Z/ (19) /Z/ (20) /Z/ (21) /0/0/0/0/ (22) /j[/ (23) /N/ (24) /A/ (25) /T/1/4/7/ (26)

CAUSE DESCRIPTION AND CORRECTIVE ACTIONS (27)

/1/0/ / The governor valve apparently tripped due to pump overspeed following a unit /

/1/1/ / trip on September 8, 1980. The cause of the overspeed was apparently an /

/1/2/ / incorrect governor setting. The governor valve was reset, the governor valve /

/1/3/ / setting adjusted to its proper setting and the periodic test on the auxiliary /

/1/4/ / feedwater pump was completed satisfactorily. /

FACILITY METHOD OF STATUS  % POWER OTHER STATUS DISCOVERY DESCRIPTION (32)

/1/5/ /Cf_(28) /0/0/0/ (29) / NA /( ) DISCOVERY

/A/ (31) / Operator Observation /

ACTIVITY CONTENT RELEASED OF RELEASE AMOUNT OF ACTIVITY (35) LOCATION OF RELEASE (36)

/1/6/ /Z[ (33) /Z/[ (34) / NA / / NA /

PERSONNEL EXPOSURES NUMBER TYPE DESCRIPTION (39)

/1/7/ /0/0/0/ (37) /Zf[ (38) / NA /

PERSONNEL INJURIES NUMBER DESCRIPTION (41)

/1/8/ /0/0/0/ (40) / NA /

LOSS OF OR DAMAGE TO FACILITY i TYPE DESCRIPTION )

/1/9/ /_Z[(42)

Z / NA /

PUBLICITY ISSUED DESCRIPTION (45) NRC USE ONLY

/2/0/ /N/ (44) / NA /////////////

NAME OF PREPARER W. R. CARTWRIGHT PHONE (703) 894-5151 l 8 910140 %

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! Virginia Electric and Power Company North Anna Power Station, Unit 1

Attachment:

Page 1 of 2 Docker No. 50-338 Report No. LER 80-078/03L-0 l Description of Event i

l At 2300 on September 8, 1980 with the unit in startup mode, the l governor valve for the steam driven auxiliary feedwater pump was found l to be in the tripped condition rendering the pump inoperable. The l governor valve apparently tripped following a reactor trip at 1956 that l day. Following the reactor trip there was no flow indication from the I

steam driven auxiliary feedwater pump to the "A" steam generator (S/G) but the "A" steam generator level was adequate and increasing.

A nonlicensed operator was sent to verify proper valve lineup. The operator verified proper valve lineup and reported that uater was leaking from the flow orifice in the line to "A" S/G. Since the level was increasing in "A" S/G and since during normal valve lineup "A" S/G is l

supplied exclusively by either normal feedwater pumps (which were tripped) or the steam driven auxiliary feedwater pump, faulty flow indication was suspected. An emergency maintenance report was issued on the auxiliary feedwater flow channel for "A" S/G.

Unit startup commenced but the unit tripped due to hi-hi S/G level. '

Unit startup was again in progress when the " TURBINE DRIVEN AUX. FD.

PUMP TRAIN A NON-AUTO CONTROL" alarm and the same alarm for Train B were noted. Investigation revealed that the governor valve had tripped closed. The valve was reset and unit startup resumed.

Probable Consequences of Occurrence Since the other auxiliary feedwater pumps were operable to remove core heat, the health and safety of the public were not affected.

Cause of Event The cause of the governor overspeed trip was apparently an incorrect govere r setting. The setting on the governor was 3.8 rather than 1.9 as require: by the periodic test for Unit 1 (Unit 2 governor valve setting is 3.8). The periodic test for Unit 1 steam driven auxiliary feedwater pump had previously been satisfactorily completed on August 13, 1980 following maintenance. It could not be determined who chane i the governor setting to 3.8 or when this was done.

The reason the water level in "A" S/G was increasing was apparently level " swell" following the overfeeding of the generator. The overfeeding of "A" S/G was caused by the loss of Vital Bus IV (see LER 80-080) which caused the main feed reg. val e to open prior to the reactor trip at 1956.

Immediate Corrective Action l The governor valve was reset on September 8,1980 which operating i

personnel thought returned the steam driven feedwater pump to operable status. On September 9,1980 at approximately 1000 it was decided to perform the periodic test on the pump. While verifying initial conditions for the test, it was discovered that the governor setting was incorrect.

The setting was changed to the correct setting of 1.9 and the test satisfactorily- completed at 1124 on September 9.

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Page 2 of 2 Scheduled Corrective Action None scheduled.

Actions Taken to Prevent Reccurrence A memorandum from the Superintendent of Operations was issued

', reminding operators of the importance of proper operation of the auxiliary feedwater system and methods of verifying proper operation. This memorandum was placed in required reading for the operators.

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