ML20072A771
| ML20072A771 | |
| Person / Time | |
|---|---|
| Site: | Byron, Braidwood, 05000000 |
| Issue date: | 06/03/1983 |
| From: | Swartz E COMMONWEALTH EDISON CO. |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| 10CFR-050.55E, 10CFR-50.55E, 6712N, NUDOCS 8306100246 | |
| Download: ML20072A771 (3) | |
Text
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/D C-Commonwealth Edison
, / ) on's First National Pirza, Chicago, Illino$
"] Address Reply to: Post Office Box 767
((Oj / Chicago, Illinois 60690 June 3, 1983 Mr. James G. Keppler, Regional Administrator
- Region III U.S. Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, IL 60137
Subject:
Cyron Station Units 1 and 2 Braidwood Station Units 1 and 2 10 CFR 50.55(e) 30 Day Report DS-416 Reactor Trip Switchgear NRC Docket Nos. 50-454/455 and 50-456/457 06ar MI. Keppler:
On May 4, 1983, the Commonwealth Edison Company Project Engineering Department notified Mr. L. McGregor of your of fice of a deficiency reportable pursuant to 10 CFR 50.55(e) regarding the DS-416 Reactor Trip Switchgear at our Byron and Braidwood Stations.
For your tracking purposes, this deficiency was assigned Number 83-06 for our Byron Station and Number 83-05 for our Braidwood Station.
This letter fulfills the thirty (30) day reporting requirements of 10 CFR 50.55(e) regarding this matter and is considered to be a final report.
Description of Deficiency The reactor trip breakers and reactor trip bypass breakers at Byron /Braidwood Stations are Westinghouse Model DS-416. Due to a discrepancy in design, there is a potential for misoperation of the undervoltage (UV) attachment in the breakers. The width of the retaining ring on the two pivot shafts of the UV trip (refer to attachment) is not compatible with the width of the groove on the pivot shafts that receives the retaining ring. The groove in the shaft receiving the retaining ring was not increased in width to be consistant with an earlier (1972) retaining ring design change. The new retaining ring is wider than the original design and does not seat properly in the existing grooves. This could cause the retaining ring to become disengaged from the pivot shaft and allow the pivot shaft to move laterally and come out of its guide hole.
8306100246 830603 JUN 61 PDR ADOCK 05000454 S PDR Y \
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Analysis of Safety Implications The deficiency described above increases the potential for misoperation of the DS-416 undervoltage attachment, thereby creating a condition wherein the reactor trip switchgear might not open on automatic demand from the reactor protection system. However, the reactor could be tripped manually by energizing the shunt coil of either reactor trip breaker to prevent any adverse safety consequences.
Corrective-Action Westingnouse will supply replacement UV attachments for the DS-416 reactor trip switchgear. The new attachments have modified (widened) grooves te acccmmodate the new retaining rings.
Manufacturing drawings have been revised and quality control procedures modifiad to assure that critical design dimensions are maintained during manufacture. Furthermore, Westinghouse is developing and will implement a procedure for installation of the new attachments on DS-416 reactor trip switchgear in the plant.
This field installation procedure will provide for proper alignment and interface of the attachment with the breaker trip shaft.
Westinghouse will supply the new UV attachments by October, 1983.
The new UV attachments will be installed and tested prior to fuel load.
Please address any questions that you or your staff may have concerning this matter to this office.
Very truly yours d#
2
. ,7 -
E. Douglas Swar z Nuclear Licensing Administrator Attachment cc: RIII Inspector - Byron RIII Inspector - Braidwood Director of Insp. and Enf.
U.S. Nuclear Commission Washington, DC 20555 6712N a
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