ML20084E043

AO 50-237/75-23:on 750511,diesel Generator Overheated After Inadvertent Fast Start & ECCS Inadvertently Initiated. Overheating Caused by Loss of Cooling Water Pump Suction. ECCS Initiation Caused by Valving Out Flow Check Valve

ML20084E043
Person / Time
Site:	Dresden
Issue date:	05/21/1975
From:	Stephenson B COMMONWEALTH EDISON CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
320-75, 5758, AO-50-237-75-23, NUDOCS 8304130539
Download: ML20084E043 (3)

Text

/Q Ccmmsnwealth Ediscn h f*g, Oo. f ir,1 NF llierio S

((X, '/ Address (,)at Ptil,. Chie'MO to. Post Othee llos 7G7 H

Ch cago. Imnom 60690

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EBG Ltr. 8320-75 Dresden !!ucicar Power Station R. R. J1 I*orric, Illinois 60h50[e'~~~ ~ N x May 21, 1975 pf,;,

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.. / fi;uLii LU cg Mr. Jcnes G. Keppler, Regional Director p,[g'(p,71976 p-Z I ff-l Directorate of Reculatory Operation-Region III U. S.

uclear Reculatory Ccrciccion

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799 Roocevelt Road

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Glen Ellyn, Illinoic 60137

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SUDJECT: REFC*iT OF Arr*':*.tL CCCURRZ:CE PIB SECTICM 6.6. A OF Ti!E T.~JiOIICf.U~

SI EC:FIC1.0IC'.!3 1*:IIT-2 DI:CLL GE*D.tTCR OVECJ14TED

References:

1) Regulatory Guide 1.16 Rev. 1 Appendix A

2) !!otification of Region III of U. S. Muelear Regulatory Cor.icolon Telephone:

P. Johnson,1510 hours0.0175 days <br />0.419 hours <br />0.0025 weeks <br />5.74555e-4 months <br /> on I~ay 11, 1975 Telegram:

J. Keppler, 1405 hours0.0163 days <br />0.39 hours <br />0.00232 weeks <br />5.346025e-4 months <br /> on le y 12, 1975 a

3) Drawing "unter M173 Report !! umber:

50-237/1975-23 Report Date:

I*.ny 21, 1975 Occurrence Date: May 11, 1975 Facility: Dresden Nuclear Power Station, Morris, Illinois 60450

_IDZ:TIFICATIC:I 0F CCCURRE!CE The Unit-2 dieccl generator overheated after an inadvertent fact start. The rcmoval of a Ri'S/ECCS instru.T.ent line check valve upset level instruments initiating ECCS. The diocel generator failure could have prevented the intended function of an engineered cafety feature systcm.

CONDITIC::S FP.IOR TO CCCUR:C:CE Unit-2 was in the cold shutdown Ir. ode during an extended refueling outage.

DESCRIIIC: CP C-CCIT.lRZ:'":

At ap;?roxir ately 0645 heura on May 11, 1975, an instrument flow check valve was diamantled, causing the loan of one leg of a Yarway level indicator. Thic.

8304130539 750521 PDR ADDCK 05000237 ra qg PDR u

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Pr. Mr.edsG. heppler f'j May 21, 197';

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s deficiency initiated th. U:.it-2 F wrconcy Core Ocelin.rSystem. The Unit-2 diciel (:enerator started Lut everhcnted due to lack ci cooling water, i

C c'."'Pl.i.".~. C1"r Cy CCJ"REE (Cperator/ Equip. ent)

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t; The innd'ic rt crt initiatic" of *l.c F^".S occurred becauce the effect of valving i

out ficw cierch valve T-Zuf-?-15A had not been adequately investigated.

i' The diecel,enerator overheated beca.cc its cooling water pumpo 1 cat cuetien.

Trarelir cereu., C and D i ere out, of cervice for cn electrical centrol I

r.odification and cencequently were blocked. A differential preccure instru~.en*.

on the traveling cerecro u;c inoperable, preventing the high differential preccure alarm fre. actuating.

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Thic occurrcnec in no way jr'opardized the health and safety of t,he ;ublic.

Unit-2 van :n cold chutdcun e.nd no work wac being dcne that potentially endangered care rcactor ecclont levcl.

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I The diccel generator uns irrodiately taken out of service and inspected for dar. age.

'.!crk was alto initiated to correct the problema with the traveling cercenc and differential precoure switch.

The station is revic.dn; irorovements in the crib hcuse operator roundo to help detect problc.n uith the travelin' cerecns and their controls. This review is scheduled for ccmpletion by June 15, 1975 FAILURE DATA Failure of the dienel i;cnerator due to this particular cequence of evento has never occurred before.

Sincerely, s

1)s % y (e D. B. Stephencon Superintendent E"S:JE4:n p PileA.~iC

-T-J W. MPPLU, K8810nal N rT_ tor:co cf Re c ry Operctions hiecopid Dan F ' /5)- D -

ion III og

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.>a Nuclo r Regul ry Commaiccion v 7F9 Roosevelt Road M

Glen E11p, II, 60137-37 g j/

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Bernard C. Rusche, Director Directorate of Licensing 148. Nuclear Regulatory Commission Washington, D.C.

20555 gUBJECT:

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, Dresden Nuclear Power Statica, Unit 2

This. will confinn s conversation with ///2

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B. B. StePhenson, Superintendent GE ~ 5-858-2660x16 (auto)

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Originator (copy)

Incident File (copy) i

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815-942-2920/2921x212' Telegram File (origwn '

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