ML20155A927
| ML20155A927 | |
| Person / Time | |
|---|---|
| Site: | Braidwood  |
| Issue date: | 05/31/1988 |
| From: | Hunsader S COMMONWEALTH EDISON CO. |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| 4733K, NUDOCS 8806130021 | |
| Download: ML20155A927 (2) | |
Text
. -
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-'N Commonwealth Edison j
f ) Address Reply to: Post Omo) Box 767 N *g /
One First NJlional Plaza Chicago, lilinois
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'u Chicago, Illinois 60690 0767 May 31, 1988.
Mr. Thomas E. Murley, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC 20555 ATTN: Document Control Desk
Subject:
Braidwood Station Unit 1
~
Application for Emergency Amendment to Facility Operating License NPF-72, Appendix A, Technical Specifications NRC Docket No. 50-456 Reference (a): May 31, 1988 S.C. Hunsader letter to T.E. Murley
Dear Mr. Murley:
Reference (a) provided, pursuant to 10 CFR 50.90, Commonwealth Edison's request for an emergency amendment to Appendix A, Technical Specifications, of Facility Operating License NPF-72.
The proposed amendment is a one-time only change for Unit 1, Cycle 1 to Technical Specifications 4.2.2.2.b, 4.2.2.3, 3.2.3.b and 3.3.3.2.a for the Moveable i
Incore Detector System.
The change proposes to reduce from ~15% to 65%, the number of incore moveable thimbles required for the system to be operable.
The purpose of this letter is to provide additional information related to the circumstances that led to the need for this amendment. This information is included in Attachment A.
Please address any questions concerning this matter to this office.
Very truly yours, S. C. Hunsader Nuclear Licensing Administrator att.
cc:
Braidwood Resident Inspector S. Sands (NRR) 1 M. Parker-State of Illinois 8806130021 880531 PDR ADOCK 05000456~
DCD p
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ATTACHMENT "A" During power ascension testing in late 1987, several Incore System Thimbles exhibited detector sticking problems.
Sixteen thimbles were cleaned during the subsequent outage.
These sixteen were chosen based on their having exhibited the worst sticking problems, prior to Unit I criticality in March, 1988 at NOp/NOT, a full core flux map was run to test the thimbles. Only one of fifty-eight thimbles exhibited sticking problems at that time.
It was thought that the detector sticking problems had been solved. On May 10, preparations were made to perform surveillance BwvS 3.1.1-5, Incore-Excore Axial Flux Quarterly Calibration (Tech Spec Table 4.3.-1 Item 2.a).
During performance of this surveillance thimble sticking problems were encountered. At onepoint only 38 thimbles were available (20 blocked).
Forty-four thimbles are required by Tech spec.
Braidwood began attempts at clearing the stock thimbles. About May 16 the available options for resolution of this issue were identified.
These included:
1)
Westinghouse method to clean paths at power using a brush on a drive cabic between the 5 path and drive mechanisms.
2)
Request Tech Spec change from the forty-four path requirement for full core flux mapping for cycle 1.
3)
Shut down and cooldown to Mode 5 and clean the blocked drives using the wet cleaning method.
I No planned shutdown of Unit 1 is upcoming.
Braidwood wanted to prevent an unneeded cycle of p16nt equipment which would be caused by a shutdown thus, eliminating option 3.
Option 1 above was being pursued.
Attempts to move the cable through the thimbles were unsuccessful which meant the brush method could not be used. Upon realization that the Westinghouse method would not be successful it was decided that an emergency Tech Spec change was necessary to preclude an adverse cycling of plant equipment as a result of an unplanned shutdown.
4733K j
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