ML19347D949

LER 80-061/01X-2:on 800708,S&W Review of Auxiliary Feedwater Sys Design Determined That,Under Certain Conditions,Pump 1-FW-P-3B Might Provide Only 335 Gpm to Steam Generator. Caused by Incorrect Preliminary Engineering Analysis

ML19347D949
Person / Time
Site:	North Anna
Issue date:	04/08/1981
From:	Cartwright W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML19347D944	List: ML19347D943 ML19347D949
References
LER-80-061-01X, LER-80-61-1X, NUDOCS 8104140518
Download: ML19347D949 (3)

Text

. k U.S. NUCLEAR REGULATORY COMMISSION LICENSEE EVENT REPORT CONTROL BLOCK / / / / / / / (1) (PLEASE PRINT OR TYPE ALL REQUIRED INFORMATION)

/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

/0/1/ g/ (6) /0/5/0/0/0/3/3/8/ (7) /0/7/0/8/8/0/ (8) / y V y W W 1/ (9)

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

/0/2/ / On July 8, 1980, a Stone & Webster review of auxiliary feedwater system /

/0/3/ / design determined that, under certain accident conditions, auxiliary /

/0/4/ / feedwater pump 1-FW-P-3B might provide only 335gpm to its steam generator /

/0/5] / versus the design basis flow of 340 gpm. This preliminary finding was reported /

/0/6/ / pursuant to T.S. 6.9.1.8.i. Subsequently, further analysis determined that the/

/0/7/ / pump would provide adequate flow. Therefore, the health and safety of the /

/0/8/ / general public were not affected. /

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

/0/9/ /C/H/ (11) /_X/ (12) [Z/ (13) /Z/Z/Z/Z/Z/Z/ (14) LZ/ (15) g/ (16)

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

(17) REPORT NUMBER /8/0/ /-/ /0/6/1/ O/ /0/1/ g/ /-/ g/

ACTION FUTURE EFFECT SHUTDOWN ATTACHMENT NPRD-4 PRIME COMP. COMPONENT o TAKEN ACTION ON PLANT METHOD HOURS SUBMITTED FORM SUB. SUPPLIER MANUFACTURER g/ (18) g/ (19) g/ (20) g/ (21) /0/0/0/0/ (22) g / (23) g/ (24) g/ (25) /Z/9/9/9/ (26)

CAUSE DESCRIPTION AND CORRECTIVE ACTIONS (27)

/1/0/ / This concern was due to preliminary engineering analysis which showed degraded /

/1/1/ / flow at accident conditions. Further analysis has revealed that the pump will /

/1/2/ / provide the required flow under the most conservative accident conditions. No /

/1/3/ / corrective action _s are required. /

/1/4/ / /

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

/1/5/ /E/ (28) /1/0/0/ (29) / NA / (30) DISCOVERY g/ (31) / Notification from A/E / ,

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

/1/6/ [Z/ (33) [Z/ (34) / NA / / NA / l PERSONNEL EXPOSURES I NUMBER TYPE DESCRIPTION (39) l

/1/7/ /0/0/0/ (37) /Z[ (38) / NA / l PERSONNEL INJURIES NUMBER DESCRIPTION (41)

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

^ LOSS OF Oh TYPE DAMAGE TO FACILITY (' )

DESCRIPTION

/9/ g[ (42) / NA /

PUBLICITY ISSUED DESCRIPTION (45) NRC USE ONLY

/2/0/ [NL (44) / NA /////////////

NAME OF PREPARER W. R. CARTWRIGHT PHONE (703) 894-5151 810.41405/T S-

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

Attachment:

Page 1 of 2 Docket No. 50-338

' Report No. LER 80-061/01X-2 Description of Event On 7"!; '.,1980, during review of auxiliary feedwater pump flow margins, Stone & Webster determined by fluid calculations that under certain accident conditions auxiliary feedwater pump 1-FW-P-3B might be unable to deliver the design flow of 340 gpm to its steam generator. It was estimated that the pump would deliver a total flow of about 355 gpm of which approximately 20 gpm would be recirculated to the Emergency Condensate Storage Tank and 335 gpm would be delivered to the steam generator. This event was reportable pursuant to T.S. 6.9.1.8.i.

Probable Consequences of Occurrence Further analysis, supported by flow testing, has confirmed that the pump is fully capable of providing the design flow. Therefore this concern is of no consequence.

Cause of Event The cause of this discrepancy was due to preliminary engineering analysis which showed degraded flow at accident conditions.

]\- Immediate Corrective Action An evaluation was performed that revealed that the pump will provide required flow under the most conservative accident conditions (main feedline break). S & W preliminary calculations predicted piping frictional head losses for 1-FW-P-3B to be 240.6 ft. for a total flow of 360 GPM. As a result, the calculations indicated that the pump could not develop sufficient head to supply the required flow.

Based on actual flow tests, the piping frictional head losses for a total flow of 360 GPM were determined to be 203.3 f t. Using this value, the calculated head required from pump 1-FW-P-3B to meet accident conditions is 2817 ft at start of accident with 1-CN-TK-1 full and 2839 ft with 1-CN-TK-1 level just above suction piping. The testing done confirmed that the pump performs as specified by vendor pump head curve. For a total pump flow of 360 GPM (20 GPM Pecire. flow), the pump will develop 2840 ft of head. This demonstrates that 1-FW-P-3B is capable of delivering the required flow of 340 GPM to its steam generator under accident conditions.

Scheduled Corrective Action No additional corrective actions are required.

Actions Taken to Prevent Recurrence No further actions are required.

Generic Implications Unit 2 auxiliary feedwater pump flow margins have been calculated and

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Attachment:

Page 2 of 2 nre satisfactory. Therefore, there are no generic implications associated with this event.

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