05000265/LER-1980-021-03, /03L-0:on 800914,core Spray Valve MO-2-1402-3A Would Not Reopen from Control Room.Caused by Sticky Torque Switch on Valve Operator.Valve Motor Operator Will Be Inspected During Next Outage

/03L-0:on 800914,core Spray Valve MO-2-1402-3A Would Not Reopen from Control Room.Caused by Sticky Torque Switch on Valve Operator.Valve Motor Operator Will Be Inspected During Next Outage

ML19344B573
Person / Time
Site:	Quad Cities
Issue date:	10/06/1980
From:	Robert Murray COMMONWEALTH EDISON CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML19344B572	List: 05000265/LER-1980-021, Forwards LER 80-021/03L-0 05000265/LER-1980-021-03, /03L-0:on 800914,core Spray Valve MO-2-1402-3A Would Not Reopen from Control Room.Caused by Sticky Torque Switch on Valve Operator.Valve Motor Operator Will Be Inspected During Next Outage
References
LER-80-021-03L-08, LER-80-21-3L-8, NUDOCS 8010210509
Download: ML19344B573 (2)

LER-1980-021, /03L-0:on 800914,core Spray Valve MO-2-1402-3A Would Not Reopen from Control Room.Caused by Sticky Torque Switch on Valve Operator.Valve Motor Operator Will Be Inspected During Next Outage

Event date:
Report date:
2651980021R03 - NRC Website

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LICENSEE EVENT REPORT CONTRGL BLOCK: l

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8 60 61 DOCKET NUMB ER 68 69 EVENT OATE 74 75 REPORT DATE 80 EVENT DESCRIPTION AND PROBABLE CONSEQUENCES h l0#2l l While performing Core Spray System Valve Operability Test, QOS 1400-2. valve M0 I lo tal i 1402-3A would not re-open from the Control Room af ter having been closed. The l

l0 l4 j l consequences of this event were minimal. The "B" Loop of Core Spray had been l

lO lsi I demonstrated operable and the M0-2-1402-3A valye was immediately manually opened so l

TTE l I that the "A" Core Spray Loop was then fully operable as required by Technical l

l01:l I Specification 3.5.A.I.

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SYSTEM

CAUSE

CAUSE COMP.

VALVE CODE CODE SUBCODE COMPONENT CODE SUSCODE SUSCOCE 10191 l Sl Fl@ lE l@ [ Al@ l V l A l L lV l0 lP [@ l Al@ l Zl@

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9 10 11 12 13 18 19 20 SEQUENTI AL OCCURAENCE PEPORT REVISION LE R;RO EVENTvkAR REPORT NO.

CODE TYPE NO.

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33 34 35 36 31 40 41 42 43 44 47 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS h lil0; l The cause of the valve not onenina is attributed to temocrarv stickina of the torcue li li i ! switch on the valve oDeratar. The valve was successfully stroked three times after' I

ii12i l the initial failure.

The valve will be left in the normally open position until thr j l1 ( 31 l next unit outage when the valve motor operator will be inspected to determine the i

ml cause of failure.

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8 9 90 STA S

% POWER OTHER STATUS IS RY DISCOVERY OdSCRIPTION Ii i s l l El@ [ 0 l 8 l 7 l@l NA l

lBl@l Routine Test l

ACTIVITY CO TENT RELEASED OF RELE ASE AMOUNT OF ACTIVITY LOCATION OF RELEASE l1 16 l l Zl @ l Z lgl NA l

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1. ERSONNEL EXPOSURES

DESCRIPTION

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,ERSO~NE L,N,tMiES OESCRiPriON@

NUveER li la I l 01 0 l Ol@l NA l

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?2 80 LOSS OF OH DAttACE TO FACILITY h8E C

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LER NUMBER: LER/R0 83-21/03L-0 11.

LICENSEE NAME:

Commonwealth Edison Company Quad-Cities Nuclear Power Station Ill.

FACILITY NAME: Unit Two IV.

DOCKET NUMBER:

050-265 V.

EVENT DESCRIPTION

On September 14, 1980, at 10 a.m., with Unit Two operating at 2196 MWt, at an electrical load of 681 MWe, the monthly Core Spray valve operability test, QOS 1400-2 was performed. The Core Spray suction valve M0-2-1402-3A would not re-open af ter having been closed; thereby rendering the A Core Spray Loop temporarily inoperable. Tcchnical Specification 3.5.A.I.

specifies that.both Core Spray subsystems shall be operable whenever irradiated fuel is in-the reactor vessel.

l The M0-2-1402-3A valve was immediately manually opened. The valve was

.then re-tested three times and was subsequently shown to operate satis-factorily. Work Request q07736 was issued to investigate the cause of the initial failure.

VI.

PROBABLE CONSEQUENCES TO THE OCCURRENCE:

The consequence of this event were minimal. Although the A Core Spray Loop was declared inoperable for a short period of time, the A loop could have quickly been made' operable by manually opening the normally open M0-l 2-1402-3A valve should the need for core cooling have arisen.

In addition-,

i the B Core Spray Loop had been demonstrated to be capable of performing Its design function.

Each loop is a full capacity system.

Vll.

CAUSE

It is hypothesized that the torque switch on the valve motor operator was temporarily sticking, thareby.resulting in the failure of 'the motor operator to latch and the valve to unseat.

The torque switch was manufactured by Limitorque, Modei No. SMB-0.

There have been numerous failures of torque switches in the past, but no pre-vious such occurrences on any Core Spray suction valves.

(

Vill.

CORRECTIVE ACTION

l The immediate corrective action taken was to manually open valve M0 1402-3A.

The' valve was stroked three times to verify operability.

During the next unit ~ outage, the valve operator will be inspected to determine l

why the failure occurred-and to make necessary adjustments as required.

In the meantime, the M0-2-1402-3A valve will remain in the open position.

l