ML20098F159

Submits Mods Identified for Completion Prior to Liquid Nitrogen Inerting of Containment.Low Temp Switch Will Be Replaced & Relocated to Improve Response Time & Eliminate Adverse Impact of Cold Outdoor Ambient Temps

ML20098F159
Person / Time
Site:	Limerick
Issue date:	09/26/1984
From:	Kemper J PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	Schwencer A Office of Nuclear Reactor Regulation
References
CON-#484-250 OL, TAC-54150, NUDOCS 8410020402
Download: ML20098F159 (3)

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PHILADELPHIA ELECTRIC COMPANY 2301 M ARKET STREET P.O. BOX 8699 PHILADELPHIA, PA.19101 JOHN S. KEMPER V IC E-PR ESID E NT susengsmeno aura mass ARCH Mr. A. Schwencer, Chief Docket Nos.: 50-352 Licensing Branch No. 2 50-353 Division of Licensing U.S. Nuclear Regulatory Cm mission Washington, DC 20555

Subject:

Limerick Generating Station, Units 1 & 2 Liquid Nitrogen Inerting Syst m

References:

1) I.E. Bulletin No. 84-01, dated 2/3/84

2) GE Service Mformation Intter No. 402, dated 2/14/84

3) I.E. Information Notice No. 84-17, dated 3/5/84

-File:'

GOVT 1-1 (NRC)

Dear Mr. Schwencer:

The reference docunents discuss concerns over the use of liquid nitrogen type inerting systems at BWR plants with Mark I and II containment - designs.

'Ihese concerns were generated by events at Georgia Power Cmpany's Hatch Unit 2, when very cold nitrogen (either liquid or gaseous) was injected into the torus air space. The

' injection stream inpinged directly upon the torus vent header, initiating brittle failure of the steel used in the header.

The portions of the reference documents that are applicable to Limerick recmmend evaluation of the liquid nitrogen vaporization systm design and operation.

The Limerick design specifically included consideration of the potential hazards of handling liquid nitrogen as discussed in FSAR Section 9.4.5.1.

The liquid nitrogen vaporization and containment inerting systems at Limerick are essentially identical to those in use at Feach Bottm Atmic Power Station.

A detailed review of the Limerick design and relevant Peach Bottom operating experience has been empleted. As a result of this review, the following modifications have been identified for cmpletion prior to the inerting of the Limerick containment (6 months after initial criticality per Technical Specification 3.10.5):

replace and relocate the existing low tenperature switch to inprove response time and eliminate the adverse impact of cold outdoor ambient taperatures

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remove existing manual bypass around law tmperature shutoff valves 8410020402 840926 1 0 PDR ADOCK 05000352 A

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• provide an automatic low tenperature isolation signal to the inerting line contairment isolation valves provide an ambient vaporizer and a topping heater to eliminate deperxlence on auxiliary steam for low flow operation provide control rom indication of the tenperature of the nitrogen gas being supplied to the containment.

The cmpletion of these modifications will provide added assurance that liquid nitrogen related failures will not occur at Limerick.

Sincerely, OCNf JIIA/cmr/09248405 cc: See Attached Service List

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cc: Judge Lawrence Brenner

'dudge Peter A. Morris-

Judge Richard F. Cole Judge Christine N. Kohl Judge Gary J. Edles Judge Reginald L. Gotchy Troy B. Conner, Jr.,. Esq.

Ann P. Hodgdon,'Esq.

Mr. Frank R. Romano Mr. Robert L. Anthony Ms. Maureen Mulligan' Charles'W. Elliot, Esc Zori G. Ferkin, Esq.

Mr. Thomas Gerusky Director, Penna. Emergency Management Agency Angus R. Love, Esq.

- David _Wersan, Esq.

-~ Robert J._Sugarman, Esq.

Martha W. Bush, Esq.

-Spence'W. Perry, Esq.

Jay M.-Gutterrez, Esq.

Atomic Safety & Licensing Appeal Board Atomic Safety & Licensing Board Panel.

Docket & Service Section Mr. James Wiggins-Mr. Tinothy R. S. Campbell

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