ML19331D815

LER 80-038/01T-0:on 800818,mode Switch in Shutdown Trip Function of Reactor Protection Sys Failed When B Vital Motor Generator Set Tripped.Caused by Relay 5A-K16B Being Energized & Relay 5A-K17B Being de-energized

ML19331D815
Person / Time
Site:	Pilgrim
Issue date:	08/29/1980
From:	Mathis C BOSTON EDISON CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML19331D812	List: ML19331D811 ML19331D815
References
LER-80-038-01T, LER-80-38-1T, NUDOCS 8009030607
Download: ML19331D815 (2)

Text

_ _

(7 77)

/ 'T LICENSEE EVENT REPORT Lj cONTRO) BLOCM: l l l l l (PLEASE PRINT CR TYPE ALL REQUIRED INFORMATION)

I0 l 18 l9 l M lUCENSEE A l P CODE l P l S14l 1 l@l 15 0 l 5 l 0 lLICENSE - l 0 NUY8ER l 0 l 0 l 0 l- l0 l 250 l@l4 26 l1 l1 l1 l 1 l@l 57 LICENSE TYPE JO l

4AT 58 lg 7

CON'T 10111 Z,"c' l L l@l 0 l 5 l 0 l- l 0 l 2 l 9 l683 @l 69 01811 l81810 l@l018REPORT 74 75 l 21918 DATE l080l@

7 8 60 61 DOCK ET NUM8ER EVENT DATE EVENT DESCRIPTION AND PROB ABLE CONSEQUENCES 01o 10121 l Contrary to Technical Specification, Table 3.1.1, the " Mode Switch in Shutdown" tri) l l function of the RPS failed when "B" vital MG set tripped. Public health and safety l

o i3, l 0 1.s l lwere not affected since movement of the mode switch through startup to shutdown would l io l3i lhave scrammed the reactor on 15% APRM trip had a scram been necessary, g 101611 _

i l0l7ll l 10181l 60 I

7 8 9 C E CODE SU8C . COMPONENT CODE SL3 CODE S l0l9l [ Il Al@ lB l@ l A l@ l Il Nl Sl Tl Rl Ul@ l S l@ g @ 19 20 7 8 9 10 11 12 13 18

,_ SEQUENTIAL OCCURRENCE REPORT REVISION EVENT YE AR R EPORT NO. CODE TYPE N O.

LER RO

@ RE R l 8l 0l l-l l0 l3 l8 l 24 26 y

27 l0 l 1l 28 29

[Tl 30 l-l 31 l 0l 32

,,,, 21 22 23 K N AC O ON PL NT ME HOURS 22 S8 IT FOR 8. SLPPLI MA UFACTURER l33X l@l34F l@ l35Z l@ W@

36 l0 l 0l0 l0 l 3/ 40 g@

41 l Nj g 42 lN l g 43 lG l0 l8 l0 lg 44 47 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS h 13 10 l ] Investigation showed that relay 5A-K16B was energized and relay 5A-K17B was de-energiz9d L1 11 I l The problem was resolved by mant ally picking up the SA-K17B which dropped out 5A-K16B l

,, ,7, jand reset the logic. A design change is being processed to provide permanent correctipn iil3l l of the problem. l l

11 141 I 80 7 8 9 A S  % POWE R OTH ER STATUS CI RY DISCOVERY DESCRIPTION N.A. l l A [gl Operational Event i 11151 l E l@ l 0 l 9 l 8 l@l ACTIVITY CO TENT RELEASED OF RELEASE AMOUNT OF ACTIVITY LOCATION OF RELEASE N.A. l l N.A. l l 1 l 6* l*l Z l @ l Z l@l PERSONNEL ExPOSSES NUMBER TYPE DESCRIPTION N.A. l ITTT1 i Oi 01 Ol@l zi@l PER$0NN E L INJURIES NUMBER DESCRIPTION y l0l0l0l@l N.A. l 7 8 9 11 12 80 LOSS OF OR DAMAGE TO FACILITY TYPE DESCRIPTION y l Zl@l N.A. l 7 8 9 10 80 E;I iISSV DE CRIPTION f8110 Oh N.A. l N

• NW llllllllllllly 7 8 9 68 69 80 ",

Charles J. Mathis 617-746-7900 o NAME OF PREPARER PHONE: $

BOST0ff EDIS0!! C0:1pAI.T

. I'ILGRD! !."JCLEAR POWER STATIO!!

DOCKET No. 50-293 Attachment to LER 80-038/01T On 8/18/80 at 1100 hours0.0127 days <br />0.306 hours <br />0.00182 weeks <br />4.1855e-4 months <br /> the "B" vital MG set failed causing the associated reactor protection system bus to go dead. When the alternate power was applied, operations noted that the annunciator " shur.down scram reset permissive" came in and stayed in. A request was made to investigate the problem with the alarm.

At 1530 hours0.0177 days <br />0.425 hours <br />0.00253 weeks <br />5.82165e-4 months <br />, investigation showed that relay SA-K16B was energized, and relay SA-K17B was de-energized.

. With this configuratica, the mode switch channel "B3" manur,L scram by. going to the shutdown position was bypassed.

The scenario of this event follows:

1. On loss of AC power 5A-K17B timed out in 2 seconds and closed contacts 1-2 and 3-4,

2. When power was re-established to the "B" RPS bus, the 5A-K16B relay picked up immediately and opened contacts 1-2 preventing SA-K17B from resetting.

3. With SA-K173 contacts 3-4 closed and SA-K16B contacts 3-4 closed, the shutdown position mode switch scram is precluded for channel "B3."

The immediate problem was resolved ar 1730 hours0.02 days <br />0.481 hours <br />0.00286 weeks <br />6.58265e-4 months <br /> by MR 80-3138 being generated to manually pick up 5A-K17B which dropped out 5A-K16B and reset the logic.

The final resolution, however, will require a design change.

.