ML19269D596

LER 79-073/01T-0 on 790517:incorrect Valve Weights Used for Stress Calculations Involving Accumulator Isolation Motor Operated Valves.Cause Unknown.Minor Adjustment to Spring Hanger Will Restore Compliance

ML19269D596
Person / Time
Site:	North Anna
Issue date:	05/31/1979
From:	Cartwright W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML19269D591	List: ML19269D590 ML19269D596
References
LER-79-073-01T, LER-79-73-1T, NUDOCS 7906050260
Download: ML19269D596 (2)

Text

NRC FORM 366 (177)

I LICENSEE EVENT REPORT CONTROL BLOCK I l l l l l l (PLE ASE PRINT OR TYPE ALL REQUIRED INFORMATION)

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I NUMBER EVENT DESCRIPTION AND PROSABLE CONSEQUENCES Oio o 2 lOn 5/17/79, Station Personnel were intormed by Westinghouse that incorrect valve weight]s

,g,3, ,were used for stress calculations involving accumulator isolation motor operated valveq.

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This event had no ef fect on the health and safety of the general public. These valves l g g g were normally maintained open during power operation. This event is reportable as perj

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I o s l 80 7 8 9 SYSTEM CAUSE CAUSE COMP. VALVE CODE CODE SUSCODE COMPONENT CODE SUBCODE SUSCODE o 9 l Sl Fl@ W@ W@ l V l A l L l V l E l X lh y@ [ D_j 13 18 19 20 7 8 9 10 11 12 SEQUENTIAL OCCURRENCE REPORT REVISION EVENT Y AR REPORT NO. CODE TYPE N O.

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44 47 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS h i 0 lThe reason the weichts unnd for 9ernan r,1cn1neinne unrn incnrrnce ic nnten nen ,e ewte l 1 i time. Feanalysis inaic,eno e,,*

s ,11 n4,4e- , , ,1 supports can withstand a seismic eventy

, , j However,ninor adjustments to four spring hangers are required to restore compliance l

, 3 lwith the original design bases.

l 11141 l 80 7 8 9 ST S  % POWER OTHER STATUS IS OV RY DISCOVERY DESCRIPTION i 5 lElh l1l0Iolh! 'd A l [Ddhi Notification hv NSSS Vondor l ACTIVITY C NTENT RELEASED OF RELEASE AVCt.NT OF ACTIVITY LOCATION OF RELEASE li 168 I9[ZJ @ L7J@l N/A I n/^ l 7 10 11 44 45 80 PERSONNEL FXPCSURES NUV4#4 'ni  ; E SCm 3710 N i 7 l0 l0 0 l@lZ lhl N/A 8

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2266 236 NU,,BER m,CR,._@

N/A l l1 la8 l9 l0 l0 l0 l@l12 7 11 80 LOSS OF OR DAMAGE TO FACILITY TYPE DE SCRIP TION l

7 i 9 8 9 lZ lhl 10 N/A 80 NRC USE ONLY L2_LJ ISSUE LN_10l @ DESCRIPTION N/A 7906050 %o (,iiiii,iii,ij 7 8 9 68 69 80 &

NAME OF PREPARER

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Virginia Electric and Power Company Attachment; Page 1 of 1 North Anna Power Station, Unit #1 Docket No. 50-338 Report No. LER 79-073/01T-0 Description of Event On 5/17/79, Westinghouse informed Vepco that in addition to the valves reported in LER/RO-79-035/01T-0, the 12 inch motor operated valves manufactured by Velan used for accumulator isolation also exceed the weight used to calculate pipe stresses. The actual valve weight is 3950 lbs. , whereas the weight used to calculate pipe stress was 3050 lbs. This event is reportable as per T.S.

6.9.2.8.L.

Probable Consequences of Occurrence Results indicate the piping and valve will not fail under a seismic event.

However, four spring hangers will require adjustment in order to comply with the original design bases. Unit 2 has the same valves and is similarly affected.

Cause of Occurrence The cause of this occurrence, the incorrect valve weights used in stress calculations, is unknown at this tice.

Immediate Corrective Action The immediate corrective action was to reanalyze the pipe and pipe supports using the correct valve weights. Results indicate that four spring hangers will require adjustments.

Scheduled Corrective Action the four spring hangers will be adjusted as soon as operating conditions permit.

Action Taken to Prevent Recurrence No further action required.

2266 237