ML20064B983

/03L-0 on 780905:a Bistable (FC-1485 in Protec Channel IV) Failed to Trip During a Periodic Test.Defective Bistable Card Was the Cause & Replaced

ML20064B983
Person / Time
Site:	North Anna
Issue date:	10/10/1978
From:	Cartwright W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:
Shared Package
ML20064B971	List: ML20064B968 ML20064B973 ML20064B983
References
LER-78-089-03L, LER-78-89-3L, NUDOCS 7810130148
Download: ML20064B983 (2)

Text

tamtmim ewnrwswa CON,THOL BLOCK: l l i

l l l l lh (PLE ASE PRINT OR TYPE ALL REQUIRED INFORMATION) l 0 l 0 l 0 l0 l025l- l04l0l1LICENSE l l1@ l1 l1 l@l$ 7 CA T S3l@

l l 0 l B19 ] l _V l A lCODE LsCE'.SEE 11 l A14 l S15 l 1 l@l 0 l LICEreSE 0 l - NUMBER 26 TYPE JO CON'T lal:l "jy l L @l 0 l 5 l 0 l 0 l0 l 3 l 3 64l8 @l0 69 l9 l0 l5 l7 l8 @l1 In EVENT DATE 74 7%

l1 lnl7 Ig80 lh REPORT OATE r B to 61 DOCKEY NUMBER EVENT DESCRIPTION AND PROBABLE CONSEQUENCES h

[o Iil l During the performance of a periodic test, it was observed that a bistable (FC-1485 l g l in protection Channel IV) associated with "Hi Steamline Flow S. I. Actuation", failed l 1r] l to trip as expected. This event is reportable as per Tech Spec 6.9.1.9.b. I r.,E I 1 1016 I l I 10171I I 1

Lo_le ] l 80 7

[ 9 DE CODE S 8CO E COMPONENTCODE SUBCOO"E SU E

[O [ j l Sl Flh Wh Wh l Il Nl Sl Tl Rl Ulh Wh lZ lh 7 8 9 10 11 12 13 18 19 20

,_ SEQUENTIAL OCCURRENCE REPORT R EVISION LE9 EVENT YE AR REPORT NO. CCOE TYPE NO.

@ ,ag/RO l7 18 l t

_.21 22 l-l 23 l0 l8 l9 l 24 26 l/l 27

! O _l 3 l 28 29 M

30 b34 W

32 TAK t A TO ON PLANT 1T HOURS S8 i FOR1 8. SUPPLIER MANUFA RER WhWh Wh 33 J4 35 l36Z jh l0 l0 l0 l0 l 37 40

{Q 41 lY 42 l@ l43N l@ l44W l 1 l 2 l 047 l@

CAUSE DESCRIPTION AND CORRECTIVE ACTIONS h l i 10 l l The bistable card proved to be defective and was replaced. The instrument loon was I i i irecalibrated and retested by the periodic test. Redundant circuit n van availnblo I g l if required by an accident situation and the health and safety of the ceneral public I

[Th l was not endangered. l I

I i 141 l 80 7 8 9 ST is  % POW E R OTHER STATUS 15 RY OlSCOVERY DESCRIPTION i 5 W h l1lOlOlhl N/A l d hl Instrument Technician Observation l AC TIVITY CO TENT nELE AsEo OF Rf LE ASE AMOUNT OF ACTIVITY LOCATION OF RELEASE 7 8 9 d h d@l to PERSON'.f L f APOSURES 11 N/A 44 l l 45 N/A 80 l

NUM8ER 1 7 l 0 l 0 l 0 lhlTYPEZ lhlN/ADESCRIPTION - l

• *

• Pe nsowE tiNju' RIES * '

• NovaEn cESCniPTiON t a lOlOl0l@l N/A l 7 8 9 11 12 80 LOSS OF OR DA'3 ACE TO FACILITY TYPE D E SC P'P TION 7

1 9 d 9 lZlhl 10 N/A 80 l

8 TION

• l'0U i 2 l a l lye @l ESCFt: N/A _ l lllllilllillli ;

l'gg*fo}3e/Qg PD R. AboCM of0-3 3F S 7Y/ o / 0 55659 8o 5 !

N A?.?E OF PREPARER W. R. Cartwright PHONE: 703-894-5151

• Virginia Electric and Power Company North Anna Power Station Unit #1 Docket No. 50-338 Report No. LER/R0 78-089/03L-0

Attachment:

Page 1 of 1 Description of Event On 9/15/78, a periodic test was performed to demonstrate the operability of the Engineered Safeguard System. Upon testing the feature for Safety Injection Actuation due to a "Hi Steamline Flow Condition with Low Steamline Pressure or Low Low Tavg", a flow bistable (FC-1485 in protection channel IV) failed to trip as expected.

Probable Consequence of Occurrence This type of failure is considered by the design criteria of the Engineered Safeguard ' System as a single failure. The system provides for this type of '

failure by the ability of redundant logic to produce the same equipment response when required by an accident situation. This was evidenced when the redundant channel was tested and found to operate satisfactorily. The occurrence of these types of failures is also provided for by the administrative requirement to per-form periodic tests to determine operability of the Engineered Safeguard System as was demonstrated by the discovery of this equipment failure. As a result of the above mentioned provisions, the health and safety of the general public was not endangered.

Cause of Occurrence The bistable proved to be defective and was replaced.  !

Scheduled Corrective Action Af ter replacing the bistable card, the instrument loop was recalibrated and retested as per the periodic test by which the problem was discovered.

Action Taken to Prevent Recurrence This is believed to be an isolated occurrence and cannot be traced to any known mode of failure'. No further action is required.

-