ML20043B114

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Suppls 900330 Response to Station Blackout Rule.Calculation of Heatup of Main Control Room Due to Loss of Ventilation Following Station Blackout Revised to Properly Account for Heat Sinks & Credit Existing Masonry Walls
ML20043B114
Person / Time
Site: Clinton Constellation icon.png
Issue date: 05/17/1990
From: Spangenberg F
ILLINOIS POWER CO.
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
U-601663, NUDOCS 9005240206
Download: ML20043B114 (1)


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1 5-17)-LP-I O CLINTON POWER STATION. P.O. HOX 678. CLINTON. ILLINOIS 61727 0678. TELEPHONE (217) 935 8881 8E.115 '

May 17, 1990

~10CFR50,63  ;

1 j' Docket No. 50-461 l

. t U. S. Nuclear Regulatory Commission:

Document Control Desk  !

Washington, D.C. 20555  ;

Subj ect: - 'Clinton Power Station Eponlemental Remoonse'to the Station Blackout Rule t l

)

Dear Sir:

This letter provides supplemental information to that provided-in Illinois Power Company (IP) letter U 601628 issued March 30-, 1990,4 '

regarding compliance with the Station Blackout Rule. In thattletter it' was reported the calculation of heatup of Clinton Power Station's Main Control Room (MCR)- due to ' loss of. ventilation following a- Station Blackout-(SBO) incorrectly credited mascnry wa11 stas heat sinks. 'The-criculation has been revised to properly account for these heat. sinks.-

Since the NUMARCl methodology for heatup calculations only allows credit I ~ for.- poured concrete walls as, heat sinks, to. properly credit. the existing masonry walls it was decided to use a computer heat transfer model to-determine-heatup of Clinton's MCR. The computer model indicated, j without forced ventilation, the MCR, temperature 'would exceed 120'F. '

during an SBO. Accordingly, plans'are being formulated to' provide a means of forced ventilation following'an~SBO. _

Although the specific details of the above' modification and implementation schedules are'still being developed, Illinois Power' i company-intends to fully comply with'the_ requirements-of 10CFR50.63-  :

(c)(4). . Implementation will be completed _ within two years :after the i Director, Office of Nuclear Reactor Regulation notifies Illinois Power -'

of the adequacy of Clinton's SB0 submittal.

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It is understood the final. .

schedule for implementing any modifications required for! compliance'with

a the rule will be established in: consultation and coordination with the NRC staff. '

Sincerely yours,= l f .

l Y.

F. A. Spa genbe

,;III .['

Manager a Licen g'and fety i

JCA/alg cc: NRC. Region III, Regional Administrator NRC Clinton Licensing Project Manager NRC Resident Office- . ,

j Illinois Department of Nuclear Safety -

-NUMARC. p>g '

9005240206 900517 t PDR P

ADOCK 05000461-PDC m

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