ML17252B413

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Letter Regarding Dresden Station Units 2 and 3 Torus-To-Drywell Vacuum Breaker Bushings
ML17252B413
Person / Time
Site: Dresden  Constellation icon.png
Issue date: 12/15/1976
From: Stephenson B
Commonwealth Edison Co
To: James Keppler
NRC/RGN-III
References
50-237/1974-27A, BBS Ltr. #76-883, LER 74-027-00, LER 74-027A-00
Download: ML17252B413 (1)


Text

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CommonweM'I Edison Dresden Nucle-wer Station R.R. #1 Morris, Illinois *so450 Telephone 815/942-2920

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___________ B~~? LTR._/l-7_6-883 De_cembei;-. l~_, 19.79 Mr. James G. Keppler, Regional Director Directorate of Regulatory Operations,£?'Region TII U. S. Nuclear Regulatory Commission 799 Roo~eyelt Road Gien Ellyn, Illinois 60137

.SUBJECT.:

Dresden Station Torus-to-Drywell Vacuum Breaker

REFERENCES:

1)

Letter from B. B. Stephenson to J. F. O'Leary dated July 29, 1974 (Abnormal Occurrence report no.

50-237 /1974-27)

2)

Drawing number:* M-25.

REPORT NUMBER:

50-237/1974-27A REPORT DATE:

December 15, 1976 OCCURRENCE DATE:

July 20, 1974 FACILITY:*.Dresden Nuclear Power Station,. Morris, Illinois

/

The referenced Abnormal Occurrence report s:tat;ed that a study was in

. progress to evaluate the possible(::iuse of phosphorus-bronze in place of teflon as a bushing material in the toru~~to-drywell vac~um breakers on Units 2 and 3.

The vacuum breaker performance has been monitored for approximately three years.

During this period three binding pi;-oblems h.;ive been experienced; two

Based on the results th~s far there is no justification for replace~ent of the teflon bu~hings with phosphorus-bron~e bushings.

Additionally, based on the reduced frequency of failures, no other action is planned at this time.

Power St?tion BBS: CES :jo cc:

Director of Inspection & Enforcement Director* of Management Information & Program Control File/NRC DEC 2 3 1976 13044

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