ML20215N840

Advises of Features & Mods to Diesel Generator Room Air Exhaust Duct Louvers & Diesel Generator Voltage Regulator Cabinets in Response to Concerns Expressed in 860916 Safety Evaluation Re Util Compliance W/Generic Ltr 81-14

ML20215N840
Person / Time
Site:	Point Beach
Issue date:	10/31/1986
From:	Fay C WISCONSIN ELECTRIC POWER CO.
To:	Harold Denton, Lear G Office of Nuclear Reactor Regulation
References
CON-NRC-86-103 GL-81-14, TAC-43669, TAC-43670, VPNPD-86-442, NUDOCS 8611070330
Download: ML20215N840 (2)

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i Wisconsin Electnc ma coursur 231 W. MICHIGAN, P.o. BOX 2046, MILWAUKEE.WI 53201 (414)277-2345 VPNPD-86-442 NRC-86-103 October 31, 1986 Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U. S. NUCLEAR REGULATORY COMMISSION Washington, D. C. 20555 Attention: Mr. George Lear, Project Director PWR Project Directorate 1 Gentlemen:

DOCKETS 50-266 AND 50-301 GENERIC LETTER 81-14 SEISMIC QUALIFICATION OF AUXILIARY FEEDWATER SYSTEM POINT BEACH NUCLEAR PLANT, UNITS 1 AND 2 By letter dated September 16, 1986., you transmitted the Safety Evaluation (SE) for our submittals in response to Generic Letter 81-14. In that letter you identified a concern that failure of the the condensate storage tanks could introduce water into the diesel generator room and subsequently onto the. diesel generator voltage regulator cabinets via the room air exhausts located on Elevation 26' adjacent to the condensate storage tanks. You requested that Wisconsin Electric notify you when modifications to address this concern were completed and provide a confirmatory analysis demonstrating.that the modifications adequately addressed the staff's concerns.

During operation of the diesel generator, air flow through the diesel generator room is from intakes on the east wall of the room, through the room, and through room air exhausts in the ceiling. Each air exhaust duct contains an axial fan to provide positive ventilation during diesel generator operation. A concrete structure housing vertically mounted louvers covers the exhaust openings at Elevation 26'. The louvers are weighted to remain shut except during fan operation and are forced to open outward by air flow from the diesel generator room. Water pressure on the outside of the louvers from a large condensate storage tank leak would tend to close the louvers. In addition, air flow during far. g operation would tend to minimize water leakage through the o louvers.

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8611070330 861031 10 PDR ADOCK 05000266 P PDR

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Mr. H. R. Denton October 31, 1986 Page 2 In addition to the room features described above, we have recently completed modifications to diesel generator voltage regulator cabinets C34 and C35 to prevent water from entering the cabinets. These modifications are designed to prevent entry of water into the cabinets during fire protection sprinkler operation. For C34, cable tray covers were provided above the two four-inch diameter open conduits which penetrate the top of the cabinet. Caulk was placed around the conduit to cabinet interfaces at all penetrations. For C35, both four-inch diameter open conduits which penetrate the cabinet top were sealed with foam, and all conduit to cabinet interfaces were sealed with caulk. The ventilation openings in both cabinets are covered with a hood to prevent water from entering the cabinets.

-We believe these room features and modifications adequately resolve your concern as expressed in the SE. We, therefore, consider all activities necessary for compliance with Generic Letter 81-14 to be complete. Should you have any questions, please. contact us.

Very truly yours,

- h j%d' C. W. Fay Vice President Nuclear Power Copy to Resident Inspector.

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