ML20058K760

Ro:On 740610,hydrogen Detonation Occurred Resulting in Blowing Out Both Air Ejector Discharge Line Rupture Discs & Releasing Off Gas from Reactor Bldg Vent.Cause Under Investigation

ML20058K760
Person / Time
Site:	Monticello
Issue date:	06/10/1974
From:	Larson C NORTHERN STATES POWER CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
NUDOCS 9102140364
Download: ML20058K760 (1)

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N O T4 T H E R N' S T A.T E s P O. W E R.

C O M P-A N'Y l

1 Nanticello, Mirmesota 55360 i

June 10,1974 i

Mr. J. G. Zeppler, Regional Director Directorate of Regulatory Operations i

Region III 799 R ssevelt Pcad Glca-Ellyn, illincis 61073 l

Dear It. Keppler:

!@TrImi.its NUCLEAR GEISPATING PUNT Dochot No. 50-263 License No. D7R-22 i

J i

D:.Kring startt:) en Jtria 10,.1974, while operating at 25% reactor p:"..Tr mid conducting on-line testing of the t=:rdified off gas holduo system, a hydrogen detonatica occtnTed resulting in blo::ing out hath nir ejector discharga lina rtatum. discs cnd releesing off ges frca the reactor build-i ing vent. Tao mimm relcasa rate was 19,500 cci/ccc for cna mir.L*.c, decreasing to bachgrcund Icrels after 2 hcurs. At no tice was tha technical j

specificatica. release limit of 210,000 uci/sec.cyproached.

4 The cause of the hydrogen detonation is imder investigation..

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Yours very truly, 1

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C. B..Larsen Pl=nt Ibnager l

CEL/Innt cc:. J P O'Icary, Directorate of Licensing G Charnoff i

Minnesota Pollutien Control Agency l

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E A Prycina j

i File I

I Copics sent by telecopier to Yepoler and O' Leary I

1 gO2140364 740610

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