ML19259C708

LER 79-014/031-0 on 790723:steam Inlet Valve Mo 2-1301-16 Failed to Close During Reactor Core Isolation Cooling Monthly Valve Operability Test.Caused by Component Failure of Torque Switch on Valve Mo 2-1301-16.Switch Replaced

ML19259C708
Person / Time
Site:	Quad Cities
Issue date:	08/01/1979
From:	Leech K COMMONWEALTH EDISON CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML19259C702	List: ML19259C701 ML19259C708
References
LER-79-014-03L-03, LER-79-14-3L-3, NUDOCS 7908140612
Download: ML19259C708 (3)

Text

NRC FpRM 366 U. S. NUCLEAR REGUL AToRY cOMMISSloN (7-77 )

LICENSEE EVENT REPORT CONTROL BLOCK: l l l l l l (PLEAsE PRIN T OR TYPE ALL hEQU! RED INFORMATION) 1 6 lo l1l 1 l L Q l A l Dl 2 l@l 0 l 0 d -lLICENSE 0l 0NUM8ER l Ol - l O! 0 l0 l@l4LICENSE 1l1l1l1l@l l l@

7 8 9 LICENSEE CODE 14 15 26 26 TYPE JQ 57 LAT$$

CON'T o i 3{,] l Ll@l 015 l 0 l 0l 0 l 2l 6 l 5 @l 01 712 l 317191@l 018 l Ol l l 71 ol@ 74 80 7 8 60 61 OOCKET NLYS ER E8 69 EVENT DATE 75 REPORT CATE EVENT DESCRIPTION AND PROBABLE CONSEQUENCES h o 2 l While performing the RCIC Monthly Valve O pe ra b i l i t y Test, procedure I o 3 ; QOS 1300-3, the MO 2-1301-16 steam inlet valve failed to close _j o 4 l (T.S. 3.7.D.1). The valve was demonstrated to open satisfactorily. l

[o Isl i The inline outboard steam valve, M0 2-1301-17, was fully operable and l o e had full isolation capability. RCIC was not rendered inoperable as a i o 7 i result of this event. As a precautionary a r. t i o n , the HPCI System was l g gy, demonstrated to be opereble. l 7 8 9 80 SYSTEM CAUSE CAUS E COMP. VALVE CODE CODE SUSCOOE COMPONENT CODE SU3 CODE SUSCODE o 9 lC l E l@ Wh Wh l V l Al L l Vl E l X lh l E lh [_Dj h 9 20 7 0 10 11 12 13 18 19

' REVISION SEQUENTI AL OCCURRENCE REPORT EVENT YE A R REPORT NO. CODE TYPE N O.

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[1]h 36 l 0l0 l 0l6 l 31 40 lY lh l Y lh l Nlh l C l 6 I 6l 5 lh 41 42 43 44 47 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS h i o i Component failure of the torque switch on valve MO 2-1301-16. When the i 1 i l switch was inspected, it was found that 'ne shaft of the switch was  !

,, , y binding and thereby opening the contacts prematurely. The torque switch g was removed and a replacement was installed. The valve was then cycled l qq; succe sfully to demonstrate ope rab i l i t y.  ;

7 8 9 80 STA  % POWER # OTHER STAT 1,lS 015 V RY CISCOVERY DESCRIPTION i 5 j E l@ 0 l 6 l 8l@l NA l lB l@l Routine Test l A TIVI TY CO TENT RELEASED OF RELEASE AP.10UNT OF ACTIVITY LOCATION OF RELEASE li 6 l Z j @ l Zl@ NA l NA l 7 d 9 10 ft 44 45 80 PERSONNEL E XPOSURES NLV8ER DESCRIPTION 1 7 l0 l 0l OjhlTYPEZlhl NA l P E R sCN N E't m u'R'i E s NuveER DESCRiPTiONh 7

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4. LER NUMBER: R0 79-14/03L-0

11. LICENSEE NAME: Commonwealth Edison Compa1y Quad-Cities Nuclear Power Station Ill. FACILITY NAME: Unit Two IV. DOCKET NUMBER: 050-265 V. EVENT DESCRIPTION:

On July 23, 19 79, while performing the RCIC Monthly Valve Operability Test, Procedure QOS 1300-3, the M0 2-1301-16 steam inlet valve failed to close. Subsequent attempts to operate and close the valve were however, successful. The valve could be opened at all times during this event. The outboard steam inlet valve, MO 2-1301-17, was fully operable and had full isolation capability. As a precautionary action, the HPCI System was demonstrated to be operable.

At 4: 00 p.m. on July 24, 1979, drywell deinerting was started, and a Unit Two load reduc ion was begun. At 12: 45 a.m. on Ju)/ 25, 1979, at an electrical load of approximately 350 MWe, a drywell entry was made and the torque switch on valve NO 2-1301-16 was replaced.

Vl. PROBABLE CONSEQUENCES OF TFL OCCURRENCE:

The RCIC system is penvided to supply make-up water to the reactor core wh .. the reactor is isolated " om the main heat sink and when the feedwater system is not available. The HPCI system provides an alternate method of supplying make-u, water to the reactor should normal feedwater be unavailable. RCIC was in fact ope ra b l e since M0-2-1301-16 could auto-open if needed. ihe HPCI System was demonstrated to be operable, and the steam supply line would have isolated via closure o f M0 1301 - 17, if necessary. Hence, the safe operation of the reactor was unaffected by this event.

Vll. CAUSE:

The cause of this event is attributed to component f a i l u re of the torque switch on valve M0 2-1301-16. When the switch was inspected, it was found that the switch shaft was binding, and thereby opening the contacts prematurely.

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e The valve operator is manufactured by Limitorque Corporation and is model SMB-000.

Vill. C O R R E C T I V E A C '__v N_:

The immeds ate corrective action was to achieve closure of the M0 2-1301-16 valve, which isolated the RCIC steam line. The HPCI system was demonstrated operable.Under work request number 3722-79, the torque switch was removed and a like-for-like replacement accomplished. Subsequent valve exercise was performed successfully.

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