B10939, Interim Deficiency Repts SD-43 Re Inadequate Welds on Seismic Anchors Used for 480-volt Load Ctrs & SD-44 Re Improper Mounting Hardware for Air Handling Unit Cooling Coils.Update Expected by 840201

Interim Deficiency Repts SD-43 Re Inadequate Welds on Seismic Anchors Used for 480-volt Load Ctrs & SD-44 Re Improper Mounting Hardware for Air Handling Unit Cooling Coils.Update Expected by 840201

ML20082L799
Person / Time
Site:	Millstone
Issue date:	11/08/1983
From:	Counsil W NORTHEAST NUCLEAR ENERGY CO., NORTHEAST UTILITIES
To:	Murley T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
10CFR-050.55E, 10CFR-50.55E, B10939, B109390, B10939050.55E, SD-43, SD-44, NUDOCS 8312050586
Download: ML20082L799 (2)

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EC .$7["~ H ARTFORD. CONNECTICUT 061410270 e (203) 666-6911 g J .'w.a., .ou uve. uw.. ew-November 8,1983 B10939 Dr. Thomas E. Murley, Regional Administrator Region i U. S. Nuclear Rebulatory Commission 631 Park Avenue King of Prussia, PA 19406

Dear Mr. Murley:

Millstone Nuclear Power Station, Unit No. 3 Reporting of Potential Significant Deficiencies in Design and Construction:

Brown Boveri 480V Load Center Anchor (SD-43); and Flakt-Bahnson Air Handling Units (SD-44)

In an October 7,1983 telephone conversation between your Mr. J. Robertson and our Mr. R. E. Lefebvre, Northeast Nuclear Energy Company (NNECO) reported two potential significant deficiencies in the construction of Millstone Unit No. 3 as required by 10CFR50.55(e). SD-43 involves inadequate welds on seismic anchors used for Brown Boveri 480V load centers. SD-44 involves improper mounting hardware used to install cooling coils in Flakt-Bahnson air handling units.

The load centers were mounted in accordance with the vendor's drawings and instruction manual by plug welding to the sill plates. During a review of the seismic test report, it was discovered that the tested load centers were attached to the test table with fillet welds instead of plug welds. The vendor has been contacted and has indicated that fillet welds must be used to seismically mount the load centers to the sill plates.

To correct this situation, af fected load centers will be modified by fillet welding to the sill plates.

A similar discrepancy was discovered in the attachment o the cooling coil units to the Flakt-Bahnson air handling units. In accordance with the vendor's drawing and instructions, the cooling coils were installed using self-tapping screws. The seismic analysis shows that nuts and bo:ts were used to attach the cooling coils to the air handling units. Flakt-Bahnson has reviewed their seismic analysis and has confirmed that nuts and bolts must be used to attach the cooling coils to the units.

In cases where cooling coils were installed using self-tapping screws, they will be changed to nuts and bolts (N&D 2772).

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We are presently unable to provide a final report on these two deficiencies because they are undergoing further review. We expect to be able to provide you with an update on or before February 1,1984.

Very truly yours,

, NORTHEAST NUCLEAR ENERGY COMPANY AMid

• W. G. Counsil Senior Vice President s

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