ML20028C449

Responds to IE Bulletin 78-03, Potential Explosive Gas Mixture Accumulations Associated W/Bwr Offgas Sys Operations. Maint Procedures Will Be Revised to Include Appropriate Caution Statements

ML20028C449
Person / Time
Site:	Nine Mile Point, 05000000
Issue date:	03/13/1978
From:	Schneider R NIAGARA MOHAWK POWER CORP.
To:	Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML20027A594	List: 05000000/LER-1977-040, Forwards LER 77-040/01T 05000000/LER-1977-040-01, /01T:on 771213,two Hydrogen Detonations Occurred in Offgas Sys & Stack Base,Resulting in Momentary Radioactive Release & Injury to One Employee.Initial Detonation Caused by Arc Strike on Instrument Tubing 05000000/LER-1977-043, Forwards LER 77-043/03L-0.Detailed Event Analysis Encl 05000000/LER-1977-043-03, /03L-0:on 771219,stack Gas Monitor Sample Probes & Mounting Beam Discovered Damaged.Caused by 771213 Stack Base Hydrogen Detonation.Monitor Probes & Support Beam Replaced & Sys Operation Restored on 771223 IR 05000245/1977033 ML20027A593 ML20027A595 ML20027A612 ML20028C393 ML20028C398 ML20028C399 ML20028C403 ML20028C405 ML20028C407 ML20028C408 ML20028C410 ML20028C411 ML20028C412 ML20028C413 ML20028C414 ML20028C415 ML20028C419 ML20028C420 ML20028C422 ML20028C423 ML20028C424 ML20028C425 ML20028C426 ML20028C427 ML20028C428 ML20028C430 ML20028C431 ML20028C432 ML20028C433 ML20028C434 ML20028C435 ML20028C436 ML20028C437 ML20028C440 ML20028C441 ML20028C442 ML20028C443 ML20028C446 ML20028C448 ML20028C449 ML20028C450 ML20028C451 ML20028C452 ML20028C453 ML20028C454 ... further results
References
FOIA-82-545, REF-SSINS-6820 IEB--78-3, IEB-78-03, IEB-78-3, NMP-0135, NMP-135, NUDOCS 8301100186
Download: ML20028C449 (1)

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NIAGARA MOHAWK POWER CORPORATION /300 ERIE BOULEVARD WEST. $YRACUSE N.Y. 32C2/ TELEPHONE (315) 47 March 13, 1978 Ah. Boyce H. Grier Ditect.or Udted States Nuclear Regulatory Commission Region 1 631 Park Avenue ICb19 of Prussia, PA.

19406 RE:.Doche.t No. 50-220-1.E.Bulletin 78-03

Dear Ah. Grier:

1.

In accordance with 1.E.Bulletin 78-03, Operations and Maintenance Procedures have been reviewed.to assure proper operation of be Of f-Gas Sys. ten in accordance with all design parme.ters.

Maintenance Procedwtes are being revised to include apptopria.te caution sta.tenents.

2.

Any Leaks in.the Off-Gas System in piphg or components up to and hcLuding the mixing jet will be into the Turbhe Building. These scilt be diluted by.the Turbine Bu. idling Ven.tilation Systen prior

.to behg released in the stack.

There ate no confhed spaces where

.the hydrogen can collec.c and reach explosive concenttalion.s.

Operating Procedures preciude bypassing the recombiners.

3.

No spaces or areas were iden.tified.

4.

From.the mixing jet 2.0 the vacuum pump,.the system is under a slight vacuum.

Titis condition atteviates any po.tential ptoblems from Leaks or Loop seats.

5.

Procedures for response.to Off-Gas Sys. ten explosions are adequate to insure ptoper operator action.

VeAy stuly youns, YF R.R. Schneider Vice Presiden.t Electtic Production I

f 8301100186 821207 PDR FDIA HIATT82-545 PDR

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