05000265/LER-1980-027-01, /01T-0:on 801024,while Performing Surveillance Check,Rhr Pump 2C Failed to Start Because Trip Interlock Signal Received from Pump Suction Valve M0-2-1001-7C.Caused by Incorrectly Adjusted Limit Switch.Switch Readjusted

/01T-0:on 801024,while Performing Surveillance Check,Rhr Pump 2C Failed to Start Because Trip Interlock Signal Received from Pump Suction Valve M0-2-1001-7C.Caused by Incorrectly Adjusted Limit Switch.Switch Readjusted

ML19339C561
Person / Time
Site:	Quad Cities
Issue date:	11/03/1980
From:	Robert Murray COMMONWEALTH EDISON CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML19339C554	List: 05000265/LER-1980-027, Forwards LER 80-027/01T-0 05000265/LER-1980-027-01, /01T-0:on 801024,while Performing Surveillance Check,Rhr Pump 2C Failed to Start Because Trip Interlock Signal Received from Pump Suction Valve M0-2-1001-7C.Caused by Incorrectly Adjusted Limit Switch.Switch Readjusted
References
LER-80-027-01T-03, LER-80-27-1T-3, NUDOCS 8011180613
Download: ML19339C561 (3)

LER-1980-027, /01T-0:on 801024,while Performing Surveillance Check,Rhr Pump 2C Failed to Start Because Trip Interlock Signal Received from Pump Suction Valve M0-2-1001-7C.Caused by Incorrectly Adjusted Limit Switch.Switch Readjusted

Event date:
Report date:
2651980027R01 - NRC Website

text

L% LL NRC., FORM 384 gd 1.lCENSEE EVENT REPORT 6@

inEass rRiNT A TvPs ALu:EtuiMEsiNFxMarim CoNTROLstOCo' I

I I

I I

l I il Ll al Al Dl 2 l@l 0 l 0 l 0 l - l 0 l 0 l 0 l-l0 l0 lo @l 4 l I l i l ll_l,j@l l

l@

o i 7

8 9 UCENSEE CooE

.t4 15 ucENSE NumeER 2h 2e uCENSE rypt 40 5 7 t.;A r $4 i

CON'T l'BTD 1% LL j@l015 l 0 l 010 l 2 l 6 l 5 l@l1 1012 l418 l0 l@li 11 l 0l 31810 l@

7 4

e0 et occxET NUweER es. 89 EVENToArt 74 75 REPORT oArt 80 EVENT DESCRIPTION AND PROSABLE CONSEQUENCES h o 2 l While performing RHR Pump Operability Surveillance, QOS 1000-2, RHR Pump 2C failed to l start because a trip Interlock signal was received irom pump suction valve MO-2-1001-l gg o e l 7C. The 1/2 Diesel Generator was out of service for maintenance and testing was l

being performed to satisfy Technical Specification 3 9/4.9-E.1.

The effects on l

o 3 g

RTin I reactor safety were not adverse. 2D RHR Pump was operable. The B Core Spray loop l

i o, I and B RHRS cooling loop were operable. Normal power was available for A & B RHRS l

pumps, A Core Spray Loop and A RHRS Containment Cooling Loop.

l g7;q g sues"o*o'E s$$5

1. ^'o*Eco 'sec'o$E couroNENT ccoE SEE"

^

Q l ClF l@ W@ y@ l Z l Zl Z l Z l Z l Z l@ y@ y @

7 8

9 to 11 12 13 te 19 20 sEQUENrtAL OCCURRENCE REPORT Revision EVENr vE AR REPoRr No.

CooE TYPE No.

@ ;LERiRO(258 l0 i L--J 10 12 17 i y

10 l i i

[_T ]

(_.]

LO_j Eg 31 32 22 23 24 26 27 28 29 30 iK N Ac o C

Nr ME O HOURS S

I FOR 8.

sOPPL MANUF C RER LE,j@[X,,j@

[X_j@

{,X_j@ - l0 10l 0l 0l [Y,j@

W@

(,N,_j@

lZl9l919l@

34 JS 36 37 40 ' el 42 43 44 47 33 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS h l ioll The limit switch on valve MO-2-1001-7C had been incorrectly adlusted after the valve 1 i i l operator was replaced.

Immediate action was to block out the valve /ouno i n te rl ock I

, 2 l relay thus establishing 2C RHR Pump operabil.ity. The limit switch was re-adjusted; l

, 3 l Electrical Maintenance was retrained. More complete testing will be specified after l maintenance on safety-related valves which utilize interlocks gl for system operation.

I 7

8 9 80 orwERstArus b

$isEoNv' oiscovERvoEscmerios @

's'r*2EY sPowER [EJ@ l 0 l 8 l 2 l@l NA l

[B_JOLRoutIne Survel1 lance l

i s

^^

Adrivery co'0 RENT AuoVNror Acuvity h l Location or RELEASE h REtEAsEo@or RELEAsEWgl NA l

NA l

]

1 6 7

8 9 10 11 44 46 80 PERSONNEL EXPOSURES NUMBER TYPE DEsCRiPrioN 10l ol 01@LZj@l 1

i 7

,ERso~NEl'i~J'iEs oEscRiRrio~@

~U

.ER NA l

l Til I 010101@l

)

8 9 11. 12 80 WE

" &^c"R,r'o'N '' "' @

I 3 7

d 9

' 10 50 PU8LICirY NRC USE ONLV 8 01118 06t3 i

i i i i, i ii,,iiii ggrac~*o~

nA

, o 7

8 9 10 68 -69 30* 4 NAME OF PREPARER PHONE:

s..

I.

LER NUMBER: LER/R0 80-27/0lT-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 Octobe-24,1980, at 8:45 p.m. with Unit Two operating at 2092 MWt and a load of 682 MWe, RHR Pump Operability Surveillance QOS 1000-2 was being performed. The 2C RHR Pump failed to start. The 1/2. Diesel Generator was out of service for maintenance at the time and Technical Specification 3.9/4.9-E.1 required demonstration of operability of the low pressure core cooling systems and the RHR containment cooling loop associated with the operable Unit Two Diesel Generator.

Since 2C pump suction valve MO-2-1001-7C had recently had maintenance performed, a possible trip Interlock assoc!ated with the pump suction valve was suspected as the probable cause of the failure of the 2C RHR pump to start. The MO-2-1001-7C valve interlock limit switch relay Kl9B was blocked open in order to prevent the valve from further not allowing the 2C RHR Pump to start. The 2C RHR Pump was subsecuently retested and demonstrated to be operable.

Work Request q08619 was initiated to investigate the cause of the MO 1001-7C suction valve Interlock malfunction.

VI.

PROBABLE CONSEQUENCES OF THE OCCURRENCE:

The effects of this occurrence on the overall safety of the reactor and safety related systems were not adverse. The 2D RHR Pump was fully ope rable. The B Core Spray Loop and the B RHRS Containment Cooling Loop were also fully operable. Also, with normal power available the A & B RHR Pumps, the A Core Spray Loop, and the A RHRS Containment Cooling Loop were operable.

Vll. CAUSE:

I The cause of this occurrence was discovered to be a ilmit switch on the pump suction valve motor operator which had been incorrectly adjusted af ter the valve operator was replaced. This misadjustment prevented the pump from starting due to the protective valve / pump interlock system.

The position limits on the switch were incorrectly set on October 22, 1980, following Installation of a neu valve operator. The valve at that time was returned to service and stroked three times successfully. No further testing was performed at that time.

1

,,..-..w r

+

Vill. CORRECTIVE ACTION:

The immediate corrective action was to block out the valve / pump inter-lock relay, thereby re-establishing operability of the 2C RHR Pump in order to satisfy Technical Specification requirements. The limit switch was re-adjusted and MO-2-1001-7C was tested satisfactorily. An in-vestigation is being conducted pursuant to this event. Emphasis is being given to Electrical Maintenance personnel of correct and accurate limit point settings. The Electrical Maintenance Department has since received additional training from a service representative of Limitorque Corporation, the manufacturer of the vcive operator.

Further, more complete testing will be specified af te.' maintenance is performed on safety-related valves, which utilize ?n.erlocks necessary for system operation.

i n