ML20043H320

LER 90-010-00:on 900518,station Experienced Inadvertent Safety Features Actuation Signal Level 1-4 Actuation W/Injection of 1,000 Gallons of Borated Water.Caused by Loss of 120-volt Ac Bus Y3.W/900618 Ltr

ML20043H320
Person / Time
Site:	Davis Besse
Issue date:	06/18/1990
From:	Storz L, Stotz J TOLEDO EDISON CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-90-010, LER-90-10, NP33-90-011, NP33-90-11, NUDOCS 9006250182
Download: ML20043H320 (2)

Text

.

, c y ._s*

. a. - - '.

EDISON PLAZA -!

300 MADISON AVENUE -  !

TOLEDO. OHIO 436524001 June 18, 1990 l Log No.s. BD90-0801 HP33-90-011 1 l

J

' Docket No. 50-346 License No. NPF-3 l l

l United States-Nuclear Regulatory Commission -i

-Document Control' Desk l Vashington, D. c. 20555 l Gentlemen f i

LER 90-010 j Davis-Besse Nuclear Power Station, Unit No. 1 Date of Occurrence - Hay 18, 1990 l i

Enclosed please find' Licensee Event Report 90-010-vhich is being written to provide 30 days notification of the subject occurrence. This report is being submitted in accordance with 10CFR50.73(a)(2)(iv). ]

Yours truly. .

aX Louis P. Storz Plant _Hanager -f Davis-Besse Nuclear Power Station j 5

LFS/plf l I

Enclosure ect Mr. A. Bert Davis Regional Administratoi USNRC Region III  ;

Mr. Paul Byron l

-DB-1 NRC Fr. Resident Inspector i

i

gg62rgggtaggs e

y9

, _____.____..__.______.J

i us.anasaa moo 6atosiv come o=

onee me

• • ' amoveo een no. eim-eim

, '. UCENSEE EVENT REPORT (LER) soomst emmen m ran as

>aosurfmasse ni D;vis-Besse Unit No. 1 0 l 5 l 0 l 0 l 0 l 3 l 4l 6 1 l0Fl0 l 1_

m$e w lnndvertent Safety 7entures Actuntion With 1*Meetion of 1,n00 Callons of Itorated Vater even oatsim 6en mo nen a neeont mars in otwee eassuties wvotves a Dock:IasuMYib 680s,ta Day veam Yeah IM'm"6 @ hoosetM Day vaan paciute han.ee 0l5l0l0g4l l l

~ ~

0\S 1l 8 9 0 9h 0l 1 l0 0l0 0 l6 1 !8 9l0

,nu 0l5l0jo1 0 t l l

t. .aus moeu oamtov .so ee.mo,,s...o,

== m 5 .e _

., x . ..n _

tui.i es.enwm es.n .imiw tem gn. _

m.sewnne _

es.sewe es.nnnen.ei gageggg OOi i0 m.sewmm _ _ _

" 'a*'n "" "*** = = = = "'

w;;w/ m.n _

JW ;ktgi-es egeteHinw) M.tspimHet es.teway.entee) o ~

[> < jD '[ es..WhH4w es.tehlGHw es N 9He ~ ~ ~ ~

,' uesames commet een two ten nei YttsPre0ht esvasseE esa' 4 ahta CCDs Jan C. Stott. Engineer - Maintenance Planning 4l 1l3 ? l 2 l1 l-l7 0514 l 4 conetste one une een saan consomewt eastvas essenioso w two assoat nei CAuge avsteW COMPONeNv

$ fg' '

t

{ Cause evFteW COMPONENT "hgh '"fgI

< mt p , s=;@?

l l l l l l l $ E ' W. <

l l l l l l {  :@iF ws s g sg 3g l l l l l l l M '

l l l l l l l eus,tememat mooat sweene ne , , , , , ,

woe ear yean "ilvon en . eoeene nennesson oam """] wo 0; 6 3l0 9l0 asernacteu ...n ta, _ . . e,a . er- nei On May 18, 1990, at 2121 hours0.0245 days <br />0.589 hours <br />0.00351 weeks <br />8.070405e-4 months <br />, the Station experienced an inadvetu nt SFAS Level 1 through 4 actuation including the injection of 1,000 gallons o( vater irom the Borated Vater Storage Tank (BVST) into the reactor via Low Pressure injection (LPI) Train 1-2. The plant was in Mode 5. At 2126 hours0.0246 days <br />0.591 hours <br />0.00352 weeks <br />8.08943e-4 months <br />, the a tuation was blocked. By 2129 hours0.0246 days <br />0.591 hours <br />0.00352 weeks <br />8.100845e-4 months <br />, decay heat removal flov was re-estan11shed.

The cause of the actuation was the loss of 120VAC Bus Y3 vhich de-energized SFAS Channel 3 vith SFAS Channel 1 High Containment Pressure module previously removed for maintenance.

Y3 de-energized unexpectedly while completing the prerequisites for DB-SC-04053, t 4160 V System Transfer and Lockout Test-buses C1 and C2. The cause is related to the changing configuration of the 120 VAC instrument system due to an ongoing refueling outage modification, Modification 86-0272. The root cause is still under investigation and vill be reported in a revision to this LER.

The NRC was notified via the ENS at 2250 hours0.026 days <br />0.625 hours <br />0.00372 weeks <br />8.56125e-4 months <br /> pet 10CFR50.72 of the ESF actuation. The injection of the vater was classified an Unusual Event per the Emergency Plan and appropriate notification of local and state officials was also made.

1 caeae _ _ _ . _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ . _ _ _ . _ _ . _ _ _ . .__ ____ _ v s cem ee wn