ML19317F756

Part 21 Re Instrumentation/Reactor Protection Sys Experiencing Loss of Electrical Ground to Instrument Common Bus W/O Loss Being Detected.Corrective Action to Probably Include Periodic Testing to Prove Ground

ML19317F756
Person / Time
Site:	Davis Besse
Issue date:	03/15/1978
From:	Roe L TOLEDO EDISON CO.
To:
References
REF-PT21-78-037-001 78-037-001, 78-37-1, NUDOCS 8001280686
Download: ML19317F756 (2)

Text

c .. o

-n 5,,

ATTACHED IS PART 21 REPORT FROM IE MAIL-UNIT - R00ft 317 E/W PART 21 IDErlTIFICATION NO. COMPANY NAftE c[o [c[ ceca 99-037-00/ DOCKET No. 50 - h v-t-DATE0F LETTER 3//{/7 F DATE DISTRIBUTED M - 2 2 '/,f ORIGINAL REPORT

!"PPLEMEftTARY g]

DISTRIBUTION: *

~R C R(R) FUEL CYCLE AND SAFEGUARDS (S)

MATERIALS (M)

NRR/ DOR (Stello) NMSS/FC&MS NRR/ DOR (Stello)

NRR/DPM (Boyd) AD/FF&MSI NMSS/SG AD/ROI (Sniezek/Seyfrit) PDR AD/SG-IE AD/RCI MIPC AD/ROI MIPC REGIONS REGIONS REGIONS NSIC -

MIPC PDR TIC PDR LPDR IE FILES (2) LPDR NSIC CENTRAL FILES-SS 396 NSIC TIC CENTRAL FILES (CHRON) TIC IE FILES (2) IE FILES (2)

CCENTRAL FILES Op CENTRAL FILES 016 CENTRAL FILES (CHRON) CENTRAL FILES (CHRON)

. CENTRAL FILES - SS 395 l ACTION: .

PRELIMINARY EVALUATION OF THE ATTACHED REPORT INDICATES LEAD RESPONSIBILITY FOR FOLLOW-UP AS SHOWN BELOW:

IE @ NRR [ NMSS ] OTHER Q FFMS '

l 80012804% f; i

, m - .

g File: 0017; 0486; M-536 9 L DO March 13, 1978 L '

Serial No. 420 v.se pc wem Docket No. 50-346 '**"*'*'."'";..*.*."

msi n Licenan No. NpF-3 ,

Mr. Jamen C. Keppler Regional Director, Region ill Of fice of InspecLion & Enforccment

u. S. Nucluar Ruxulatory Cocciccion 799 Roosevelt Road Glan Ellyn, 1111uvis 60137

Dear Mr. Kepplar:

This is a report of a concern wherein a 1cas of electrical ground could I constitute a wubstantial safety hacerd, as defined by 10 CFR 21.21(b),

in the NI/RPS (Nuclear Instrumentation / Reactor Protection Sywtem).

The N1/RPS was supplied by Babcock & Wilecx. I An NI/RPS channel cay cxpcrience a loss of elactrical grcund to its instru-mant co= mon bus without the loss being cvident and without causing a channel trip, ou vus previously assomad; theratore, the potential existw for a loss of ground to occur withour being detected. A safety hatard is created if a subsequent fault is than imposed upon the system. This might reAult in more than one channel being adversely affweted to the extent that there could be a major reduction in the degree of protection. However, just the

- loan of ground by itself vill not prevent the RPS trip function.

The evaluaeton and identification that such an occurrence could constitute a subatantial matety hazard was reviewed with me on March 10, 1978. This inatter was reported to your Mr. R. Knop on March 10, 1978.

MW informad us that they were luforming other users of similar fac111tles.

The corrective action to be taken has not been fully Avaluated, but would probably include periodic teuting to prove ground.

Yours very truly, g

LER:ss

- . ~ ~ . . . .

fl$f THE TUtEDO EDr5DN CCMPANY EDISON PL A2A 300 MAO!SCN AVENUE TCLECC. CHiQ 4252 _,

.