ML17252A229
| ML17252A229 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 08/31/1976 |
| From: | Stephenson B Commonwealth Edison Co |
| To: | James Keppler NRC/RGN-III |
| References | |
| BBS76-642 | |
| Download: ML17252A229 (1) | |
Text
Commonwei6Edison Dresden Nuclea;-er Station R.R. #1 Morris, Illinois 60450 Telephone 815/942-2920 BBS Ltr. #76-642 REGULATORY DOCKET FILE COPY Mr. James G. Keppler, Regional Director Directorate of Regulat6ry Operations-- Region U.S. Nuclear Regulatory Commission 799 Roosevelt Road Gleri Ellyn, Illinois 60137 111
SUBJECT:
B~*esd~J1* -Uni t-3 Condenser Low Vacuum Scram Switches
References:
- 1)
Letter to J.F. 61Leary from w:P.
22, 1974
- 2)
P & ID M-346 Report Date:
AugusUJl, 1976 Occurrence Date:
January 14, 1974 INTRODUCTION Under "Corrective Action" of the above, it was stated that the existing Bark d e condenser low vacuum scram switches appeared to lack acceptable repeatability~ To correct the problem, the Barksdale.switches *were to be replaced with Static-0-Ring C6rporation vacuum swltches which had proved to be very reliable in similar applications.
RESOLUTION After qualitative testing,~the proposed substitution of*the Static-0-Ring switch was judged to be ~~u*n.des-:i'rabfe;*,because of the switch's seismic 1 imita~*.,.
- £Ions~, Furthermore, the performance of the condenser 1 ow vacuum scram swi tthes ovei-the intervening 34-month period indicates that the Barksdale switches have stabilized significantly.
The maximum d~ift exhibited by any of these switches over this period has been 0.6 in Hg, which occurred once on PS 503C.
By adjusting these switches to the Dresden setpoint band ~f 23.J + 0.2 in ~g, all setpoint variations have remained well within* Technical Specification *:
limits.
Since the existing Barksdale switches on Unit-3 appear to be performing as designed, no corrective action is deemed necessary.
BBS :.Wm: bbc SEP 10 1976 B.B. Stephenson Station Superintendent Dresden Nuclear Power Station
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