ML20205J201

Forwards Annotated Draft Info Notice 99-XX Re Inadvertent Discharge of Carbon Dioxide Fire Suppression Sys in Cable Spreading Room,Reflecting Util Changes

ML20205J201
Person / Time
Site:	Millstone
Issue date:	03/15/1999
From:	Andersen J NRC (Affiliation Not Assigned)
To:	NRC (Affiliation Not Assigned)
References
NUDOCS 9904090224
Download: ML20205J201 (4)

Text

March 15,1999 MEMORANDUM TO: Docket File 50-423 FROM: James W. Anderson, Project Project Dwectorate 1-2 Dmaion of Uconsing Project Ma Office of Nuclear Reactor Regulation

SUBJECT:

MILLSTONE NUCLEAR POWER STATIO , UNIT 3 - DRAFT INFORMATION NOTICE 99-XX On February 11,1999, the NRC staff request Northeast Nuclear linergy Company (NNECO) to review a draft information Nobce (IN) to ensure the technical infransbon regarding the event was accurate. The draft IN desenbod the inadvertent discharpa of a carbon dioxide fire suppression system in the cable spreadmg room at Millstone Unit 3.

On February 19,1999, NNECO faxed its comments regEding the IN to the staff. The enclosure documents NNECO's comments.

Attachment:

As stated DISTRIBUTION: origina1 signed by J.Andersen PUBLIC Docket Filo PDI-2 Reading EAdensam JAnderson TClark OFFICE PDl-2/PM PDl-2/LA PDlk NAME JAndersen:cw TClarkN S DATE 3 l'b 3 / P/99 3/lb99 OFFICIAL RECORD COPY DOCUMENT NAME: A:\lN.COMM.WPD 1

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NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. m1

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MEMORANDUM TO: Docket File 50423 FROM: James W. Anderson, Project Manager 3f/

Project Directorate 1-2 f Division of Licensing Proket Managanent .

Office of Nuclear Reactor Regulation

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SUBJECT:

MILLSTONE NUCLEAR POWER STATION, UNIT 3 - DRAFT INFORMATION NOTICE 99-XX On February 11,1999, the NRC staff request Northeast Nuclear Energy Company (NNECO) to review a draft information Notice (lN) to ensure the technical information regarding the event i' was accurate. The draft IN desenbod the inadvertent discharge of a carbon dioxide fire suppression system in the cable spreading room at Millstone Unit 3.

On February 19,1999, NNECO faxed its comments regarding the IN to the staff. The enclosure docume NNECO's comments.

i Attachment As stated l

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NO.933 D64 il 4 .

IN 99-10(

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March xx.1999 d Page 2 of 4 ,

Description of Circumstane n q

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On January 15,1999 at 5# p CO2 fire suppression . with the plant at full power. an inadvertent discharge of the

!j ocurred in the Mastone Unit 3 cable spreading room. At h MeUstone 4 Sa- ne 3, the cable spreading room is located in the control building direct eh e in the servicectuation cui was caused when a non.ncense nt epipmegpp'erator blew cust off a pnnted circuit

'j die 4erN ".; h i 4 to ted in the cab's spreading ard M O .

,, mC W o .... ,_....,J panel. The panel

t is located in the service buHdin , not the control buildinge e' ' hladtpersonnalin t

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2; 7:57 m. .i me ame of the discharge. Shg after .i to have migrated down into the ewitchgear rooms locati ~ 2 was rourfd

.; direct) ow l room. Approximately 37 minutes afterinitiation, the t ' ' e 0 j a portab i measure the concentration of CO2 in one of the Con stairwells ( l

> access to the controt room, the cable spreading room i was off scale high indicating that the CO2 concentration ear rooms). The reading

} ,, ., ss of 50,000 parts per million (ppm). The current NRC Regulatory Guide 1.1$;,1cxicity rec limit for CO2 is

.. 10,000 ppm'. On the oasis of this indication, the licensee de 3 i a uninhabitable. '

Approximately 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> after the CO2 dischar j ligned ntrolbuilding purge system to remove CO2 from the switchgest oms-purging first because they contained imp 6Nant pled s were selected for shutdown panel uch as the auxiliary and smoke from various controt bui,9fiig areThe m designedpurge system to remove CO2 ignon.sa,1(ty

~ # lacing trie purge system in service diverted air from the control room to the setWear room relative to the caote spreadjng roomi. , is los whic$wered the pressure in the cor' .

allowed CO2 from the cab spreading to ring of pressure in the controlro may he j nahge concentra ' fCO2rio to up through penstrations into in trol

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onge g;lfTeo inedik ppm in the control room, the operators parattiiv{ ) as required by their procedures. The il 2 in t it began to l

. %The o rs, m toached a peak level in excess of 17,000 ppm before j successfuu o o *a SCBA for approximately 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> until the CO2 was he c ,

Discussen ' 'u ..

8 A rewfs[fw of this event b fie$

licensee identified several design and personnel safety issues. i fiThelable spreading roem CO2 system is designed to automaticalty actuate in .

iA ..The system is eqdi$ ped with alarms to wam personnel in the cable spread' bding dischars I

% CO2 to allow time to evacuate the cable spreading r O. . . . l

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rent NRC tonicity limit for CO2, specified in Res. Guide t.7s, is 10000 ppm. Plam personnel exposed to CO2 need to be proucted by self carnained brosedng apparatus before this!

concentration is reached in the proposed revision to Reg. Guide 1.78, the toxicity lirnit for C raised to 40000 ppm. This new hmit is based on the immediately Dangerous t concentration of CO2, estabhshed by the National lastinne for Occupational Safety a i

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FEB-19-99 FR103:03 PM NUCLEAR 1.10ENSING SVCS. FAX NO. 860 440 2091 P.01

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] March xx.1999 Page 3 of 4

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p e_. . r The licensee had previously modified automatic

'j CO2 fire protection systems in other areas of the plant so that they could only be actuated m nusuy. Aner mis evem. in, nssnees ws..,-v me automatic runcison of the CO2 system for j; the cable spreoding room and implemented appropriate compensatory measures. The license

, is evolusting permanent changes to avoid future inadvertent CO2 dscherges.

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, The migration of CO2 into three separate fire zones may have adverselfsfrecited the oper

?' ability to shut down the plant during a five in the cable spreh4ng roomhA Gyore fire in the I cable spreading room may adversely affect the operatord726ility to safet the plant from the control room. in the event that the operators & required tcMiva' sontrol

{ b room, pisnt procedures require operators to shutdown Wp plant fatWn the a panel and other panels which are located nr. the swnch T r roorh. During this event, the CO2 own

g concep4 ration at the auxiliary snutdown panel would p (secess withgCBA.

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in 199f.h heensee suspended the formal SCBA trainittiaV@NRficahn p t

erstors except thos_a who were members of the firtMri __

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projected post accident radiation levels and.il@oM@"his liMases inw the' detogrrnstion con was ,

o fr,sa t,1Ae However, this determination failed to conskTr Co % c .s fbg in N Reguistory Guide 1.78. Fortunately, dutieig l this

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nt. El "vh ble in the contr i area and at various other !ocations eround the s% Althos in' nd qualificatierts for all plant operato*e were not current, all.the pisnt perators t$it were on shrft dunng the event had prtviously been trained and qualified with t I CBA and%onsequently they were able to perform their dutiet using the SCOA. To i hcensee replaced the Unit 3 SC8'A with 5 nication between the operators, the n

' it 2 which had an improved type of radio communicationyystem. /tredddition, so perators did not have corrective lenses which wers'co*mpatible witffthF@,8A face masks. As an immediate corrective action the licensee reMustified alt plant operdtbrs for SCSA use The licensee is evaluatirig the need to !

reinstate the $C'BA qualification program for plant operators on a permanent basis. This suspension of SCSA quahficationwa ttir plant operatots only and did not affect fire bhgade membe's whosere t d qu ed.

The d#scharge of CO2 s'Vfo

$sesity alarm on the cable spreading room door. A securtty k officeir was instructed tonefMthe door alarm but to not open the door. The guard entered the stairwell and ascendeo the stairs to the cable spreading room. Upon approaching the cable s

sp; reading room, the officer smelled wintergreen (which is discharged with the CO2 to produc on. odor for personnel safety) and was engulfed in a mist that he concluded was CO2 Tne, offio' stheid his breath and rapidly exited the buildino. The licensee's root cause team recoismonded

.g that procedures for isolating areas potentially affected by CO2 be reviewed.

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