ML20133H647

Potential Significant Deficiency Rept SD-85 Re Seismic Interaction of Flux Mapping Sys W/Seal & Table/Bottom Mounted Instrumentation.Initially Reported on 850726. Condition Under Investigation.Next Rept Expected by 850912

ML20133H647
Person / Time
Site:	Millstone
Issue date:	07/26/1985
From:	Opeka J, Sears C NORTHEAST NUCLEAR ENERGY CO., NORTHEAST UTILITIES
To:	Murley T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
F0809A, F809A, SD-85, NUDOCS 8508090436
Download: ML20133H647 (2)

Text

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NORT1 MAST UTILITIES o.ner orrico. . seio n street. seriin. Connecticut

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(203) 665-5000 July 26,1985 Docket No. 50-423 o F0309A Dr. Thomas E. Murley Regional Administrator U. S. Nuclear Regulatory Commission Region 1 631 Park Avenue King of Prussia, PA 19406

Reference:

(1) I&E Notice 85-45.

Dear Dr. Murley:

Millstone Nuclear Power Station, Unit No. 3 Reporting of Potential Significant Deficiencies in Accordance with 10CFR50.55(e):

Seismic Interaction Between the Flux Mapping System and Seal Table (SD-85)

In a July 26, 1985 telephone conversation between your Mr. H. F. VanKessel and our Mr. P. 3. Quinlan, Northeast Nuclear Energy Company (NNECO) reported a potential significant deficiency in the design of Millstone Unit No. 3 in accordance with 10CFR50.55(e). The potential significant deficiency involved the potential seismic interaction of the flux mapping system with the seal table / bottom mounted instrumentation, Reference 1.

The Millstone Unit No. 3 flux mapping equipment is Category 2 but is installed directly above the seal table which constitutes the pressure boundary between the guide tubes for the incore instrumentation and the reactor coolant system.

Failure of the equipment support during a seismic event could cause damage to ,

the instrument tubing / scal table resulting in a small break LOCA. The flux 1 mapping equipment has not been analyzed for structural integrity during an SSE event. This condition is currently under evaluation by both Stone & Webster Engineering Corporation and Westinghouse.

8508090436 850726 PDR ADOCK 05000423 S PDR l l

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Until additional information is obtained, a final report cannot be provided. We will provide an update on this matter by September 12,1985.

Very truly yours, NORTHEAST NUCLEAR ENERGY COMPANY

b. .b J. F. Opeka '

Senior Vice President By: C. F. Sears Vice President cc: Mr. 3. M. Taylor, Director Division of Inspection and Enforcement U. S. Nuclear Regulatory Commission Washington, D. C. 20555