05000336/LER-1990-010

LER 90-010-00:on 900621,door Identified in Configuration Not Consistent W/Bechtel Design Drawings During High Energy Line Review.Caused by Lack of Knowledge of Requirements.Double Door reinforced.W/900720 Ltr

ML20055H574
Person / Time
Site:	Millstone
Issue date:	07/20/1990
From:	Baumann P, Scace S NORTHEAST NUCLEAR ENERGY CO., NORTHEAST UTILITIES
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-90-010-02, LER-90-10-2, MP-90-726, NUDOCS 9007270013
Download: ML20055H574 (3)

LER-2090-010,

Event date:
Report date:
3362090010R00 - NRC Website

text

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l gg' General Offices Selden Street Berir. Connect! cut l *[e IeNsYcDiettNmcEn7

'y' NES'as7EtiDservD'Eany P.O. BOX 270 HARTFORD. CONNECTICUT 06414-0270

_ Northeast No F Energy Company (203)665-5000  !

July 20, 1990 MP-90-726 1 Re: 10CFR50.73(a)(2)(ii) 1 U.S. Nuclear Regulatory Commission Document Control Desk ,

Washington, D.C. 20555

Reference:

Facility Operating License No.' DPR-65 Docket No. 50-336 Licensee Event Report 90-010-00 Gentlemen:

This letter forwards Licensee Event Report 90-010-00 required to be submitted within thirty (30) days pursuant to paragraph 50.73(a)(2)(ii).  !

Very truly yours, ,

NORTHEAST NUCLEAR ENERGY COMPANY 9

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Stephe E. Scace Director, Millstone Station SES/PHB:mo

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Attachment:

LER 90-010-00 cc: T. T. Martin, Region 1 Administrator W. J. Raymond, Senior Resident Inspector, Millstone Unit Nos.1, 2 and 3 G. S. Viising, NRC Project Manager, Millstone Unit No. 2 l.

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9007270013 900720 PDR ADOCK 0500o336 3 PDC hhN

NHC fori 344 U.S touCLEAR REGULATORY COMMISSION APPROVED OMt3 NO. 3160-0104 4-40) E XP:AE 6: o r30 /92 Estimated tucen por fCsitanse to comply with tnis setormation cohection reavest: 60.0 tys. Forw a'd LICENSEE EVENT REPORT (LER) E C 1s 0'a' O m%e % *a' E !*/lo U u"s' il' .4 Regwatory Commisseon. Washmpton DC 20666. and to the Papefwork heoucitan Prole 01 (316D-01 Del, Ottice o' Management and buooet. Wagnmoton. DC 20603.

F AClJTv NAME (1) DOCPd1 NUMMh(As "M Millstone Nuclear Power Station Unit 2 0l s l 010101313 l s 1lod0l2 w uE << 3 High Energy Line Break Door Discrepancy E VE NT D AT E (51 L F A MMPF A #6) AFOOnt DAtt rti OTHE A F ACit ; TIE S INvol vrD #p s MONT& DAY YEAR YEAR E MONTH DAY YEAA F ACIUT Y NAMES 01sIofolof I I O 6 2l1 9 0 0 l0 0l1l0 0l 0 0l7 2l0 9l0 olslololol l l OPERATING 1His REPORT IS BEING BUBMrtTED puesVANT To THE REOLNREMENTS O8 to CFR t- (Cneen one or more of the followmpMit t I

20 402tbi 20 402tc) 60 73(a)(2)(ev) 73 71tD) po p -

20 406(al(1)(o 60 36(c)(1) 60 73(a)(2)(v) 73 71tc)

YiE ' 1l0l0 20 406ta)(1)(io 60.as teii2) 60.73. f a)(2nvio _ (TgR (6 fQ 20 40$la)(1)(liu Text, NWForm 366A) 60 73(alf2)(0 60 731a)(2)lvill)l A) m - - -

< 20 406tal(1)(iv) \' 60. 73 (a)(2) f 60 60.73sa)(2Hveh)(B) 20 408,#ai r1Hiv) 60.73la H2)f 00 60 73 tam 2hni LICPNSEF CONT ACT FOA TH'S LE A #12i NAME TELEPHONE NUMBE A A4EA CODE Philipp H. Baumann Jr., Ext 5211 2l0l3 4l4l7l-l1l7l9l1 COMP LFTE ONE LINE FOA F ACw COMDONENT F AtVAE DESC A' BED IN THi$ AFPOAT f13)

CAU$E SYSTEM COMPONEt4T Mh)hC+ 7d CAU$E SY$ TEM COMPONENT h)Nh

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MONTH DAY YEAR

$JBMi$ $3ON D*TE ('6' 7 vES m ves. comoieie ExrhCTED suBuissioN uTEi ~~"} No 1 l2 3l1 9l0 ABSTRACT (Limit to 1400 spaces,1.4 . approximately fitt wm singte-sD&Ce typewritten hnes) (16)

With the plant at 100cc power; during a High Energy Line Break (HELB) Review /Walkdown on June 20,1990 a door was identified as being in a configJration not Consistent with Bechtel's design drawings. The door is a double door on the north side of the 4160V switchgear room on the 56'-6* elevation of the turbine building.

Subsequent investigation led to the determination that the double door did not meet the HELB requirements of the origmal Bechtel analysis. On June 21, at 1430 hours0.0166 days <br />0.397 hours <br />0.00236 weeks <br />5.44115e-4 months <br /> Engineermg initiated work to reinforce these doors to meet the HELB requirements, The turbine building rollup door was fully opened to ensure that the turbine building would not become overpressuri2ed in the event of a HELB. Work was immediately initiated to design reinforcements for the door and the mstallation of strongbacks was initiated. Reinforcement of the door was comp eted on June 22, 1990.

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! Estimatec buroen por essponse to comph with tnis

) ' "'***"*'**'**E' 60 0 " ' * *' o LICENSEE EVENT REPORT (LER) c'"om"nents regarcing Os'oen estimate to the"Reewos TEXT CONTINUA 7 TON anc neowts unnagement erar.cn m-630n v s Na a<

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Management anc Bu' toe' Wasfunmon DC 23501 F AclLfTV NAME l1 + DOcAE' NJMBt 5$ IF ' J D P M 4PFA 't- F AGE i3' VEAA Niillstone Nuclear Power Stauon l ""

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1. Des rmoon of Event On June 21,1990. with the plant m mode 1.1009 power, the unit's Engmeeting Department was mtormed that the double door on the north side of the 56 -6' elevatior 4160\' switchgear room was in a conhpuranon which did not meet the assurnpuons rnade in the original HELB analysis The 4160\'

room contains breakers for one tram of salen related components. Iniual operator action was to red-tag the Turbine building rollup door m the open posioon This was the oniv operator required acuan This allowed for a release path to atmosphere to easure that turbine buildmg mternal pressure could be ieheved through the rollup door. Work was immediatch minated to reinlcree the door to withstand a HELD Remforcement of the doors by the instalianon of strongbacks was completed on the followmg day There were no automaut or manualh minated safets system responses as a result of this event.

11 Cause of Evem At some ome after imual construcuon the door was modified (most hkeh to remove a large piece of equipmem from the room) and neser restored to its origmal design The root cause of the event is a lack of knowledge of the HELB requirements lor the area Ill Anahm of Event This report a bemp submitted pursuant to the requirements of 10CFR50 "'. Nail 2ihn( A & B) " Any event or condiuon durmg operation that results in a condinon of the nuclear power plant, meludmg its prmcipal safety barriers. bemp serioush degraded, or results m the nuclear power plant bemp. a in an unanahzed condinon tha' sigruhcanth compromnes plant safety, b in a condiuon that is outside the design basis of the plant ' in evaluatm> the salet> consequences of this event the Bechtel analysis assumes that there will be no tailures of salet) related equipmem during a HELB If a HELB were to occur and this door failed. one tram of safets related components would be affected The turbine buildiny rollup door was immediateh fulh opened to povide a steam release path to ensure that the doors would not f ail m the event of a HELB l\' Correcuse Acuori in order to protect the equipment m the 4160\' room from a HELB. the double door was remforced with strong backs These suong backs were designed to prevent tne door from fathng open when exposed to the accident pres <ure of .5 PSIG The HELB requirements and hmnauons for all vnal areas are currenth under revieu The results of the review and ans additional correcure acuorn wil! be described m an update repon

\' Additional Inf ormanon Similar LEPJs- 40-005-00 Ells Component Code Door - DR rg5 o.- m