ML20038D098

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Forwards LER 81-070/01T-0.Detailed Event Analysis Encl
ML20038D098
Person / Time
Site: Dresden Constellation icon.png
Issue date: 12/02/1981
From: Scott D
COMMONWEALTH EDISON CO.
To: James Keppler
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML20038D099 List:
References
81-946, NUDOCS 8112160059
Download: ML20038D098 (2)


Text

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.\. 1 N Commonwealth Edison

, e O Dresden Nuclear Power St tion g~ ( ' . R R. #1 Morris, Illinois 60450 Telephone 815/942-2920 December 2, 1981 f

DJS Ltr. #81-946 James G. Keppler, Regional Director ,

Directorate of Regulatory Operations - Region III U.S. Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, IL- 60137

't Reportable Occurrence Report #81-70/01T-0, Docket #050-237 is being.

submitted to your office in accordance with Dresden Nuclear Power Station Technical Specification 6.6.B.l.(e), failure or malfunction of one or more components which prevents or could prevent, by itself, ,

and the fulfillment of the functional requirements of system (s) used to cope with accidents analyzed in the SAR.

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\d D. J. Scott _4 '$ffayggc ,A L, Station Superintendent W7 #

Dresden Nuclear Power Statich '

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Enclosure cc: Director of Inspection & Enforcement l Director of Management Information & Program Control ,

U.S. NRC, Document Management Branch File /NRC Ib  ;

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I ATTACHMENT TO LICENSEE EVENT REPORT '81-70/01T-0 COMMONWEALTH EDISON COW ANY (C'a'El DRESDEN UNIT 2 (ILDRS-2)

DOCKET # 050-237 During normal unit operations, following a failure of the weld that attaches the operator mounting flange to the valve yoke of core spray full flow test valve M02-1402-4B, an inspection of the operator mounting flange of M02-1402-4A valve was performed and crack indications were found over ,

approximately 2/3 of the circumference weld. The core spray system was declared inoperable, per Tech. Spec. 3.5.A.l. There was no effect to public

. health or safety. This event is of minimum safety significance because the other ECCS were operable. Previous occurrence; R.O. 50-237/81-69.

The cause of the cracked weld on the M02-1402-4B valve operator flange was due to a poorly made fillet veld. When the operator mounting flange of M02-1402-4B was inspected, it was observed that fusion of the veld was not uniform around the circumference of the flange and it eventually failed. The flange of M02-1402-4B was machined and reattached to the yoke with a deep fillet weld. The crack on weld of M02-1402-4A was ground off and a new fillet weld was applied circumferential1y around the flange. DOS 1400-2 will continue to be performed monthly -to verify core spray valve operability.

. The U-3 core spray system has two valves of similar function and type (M03-1402-44. and M03-1402-4B). An inspection was performed and the welds around the operator flange were found to be in good condition.

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