ML19276H534

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Forwards Addl Info for Safety Evaluation Re Fire Protection Sys.Info Documents Verbal Understanding Re Item 3.2.2 on Protection of Redundant Cable Trays
ML19276H534
Person / Time
Site: Millstone Dominion icon.png
Issue date: 11/21/1979
From: Counsil W
NORTHEAST UTILITIES
To: Reid R
Office of Nuclear Reactor Regulation
References
NUDOCS 7911290375
Download: ML19276H534 (4)


Text

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November 21, 1979 Docket No. 50-336 Director of Nuclear Reactor Regulation Attn: Mr. R. Reid, Chief Operating Reactors Branch #4 U. S. Nuclear Regttlatory Commission Washington, D. C. 20555

Reference:

(1) W. G. Counsil letter to D. L. Ziemann and R. Reid dated October 9, 1979.

Gentlemen:

Millstone Nuclear Power Station, Unit No. 2 Additional Information, Fire Protection In Attachment (3) of Reference (^.), Northeast Nuclear Energy Company (NNECO) provided an evaluation of the NRC SER Item 3.2.2, Protection of Redundant Cable Trays. Subsequent telephone conversations with the NRC Staff have identified the need for additional clarification, which is provided in Attachment 1.

The intent of the Attachment is to formally document the verbal understanding reached between our respective Staffs.

Very truly yours, NORTHEAST NUCLEAR ENERGY COMPANY

/} ( ((.4'l W. G. Couns'il Vice President Attachment 1421 213 7 9110 D 0 3 75 0

DOCKET NO. 50-336 ATTACHMENT 1 MILLSTONE NUCLEAR POW.1 STATION, UNIT NO. 2 FIRE PROTECTION ADDITIONAL INFCRMATION 1 421 ?i4 NOVEMBER, 1979

NRC-SER ITEM 3.2.2 PROTECTION OF REDUNDANT CABLE TRAYS NRC Concern The consequences of fire damage to systems required for safe shutdown will be determined where the physical separation of cables in the auxiliary building may not preclude damage to redundant safety related systems. Fire retardant coating, automatic sprinkler, suitable fire barriers or early warning detection will be provided to assure that fire damage does not result in a loss of shutdown capability where prompt action is not taken to suppress fires in these areas.

Response

The requested evaluation was completed, and agreed upon modifications were documented in the October 9, 1979 submittal from W. G. Counsil to D. L. Ziemann. The following additional clarification is provided.

1. Elevation -45', Zone 1A, Columm F. 8/H. 2 and 16.6/17. 2 No change, as documented in the October 9, 1979 package.
2. Elevation -45 ' , Zone A-1A, Columns F.8/H.2 and 17.2/18.4 No change, as documented in the July 31, 1979 package.
3. Elevation -25', Zone A-9, Charging pump Area No change, as documented in the July 31, 1979 package.
4. Elevation -5', Zone A-18, Columns F.3/F.8 and 18.9/19.G pipe penetration Room The new position agreed upon for this area is that ionization detectors will be installed above the Z1 trays to provide sur-veillance for this cross-over. Also, cable trays involved in the cross-over will be completely enclosed. Enclosing the cable trays will be in lieu of fire rated barriers.
5. Elevation -5', Zone A-14, Columns F.8/H.2 and 18.1 No change, as documented in the October 9, 1979 package.
6. Elevation 5', Zone A-14, Columns L.5/M.4 and 17.7 No change, as documented in the July 31, 1979 package.
7. Elevation 5', Zone A-14, Columns M.4 and 17.8 No change, as documented in the July 31, 1979 package.

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NRC-SER ITEM 3.2.2 PROTECTION OF REDUNDANT CABLE TRAYS

8. Elevation 14'6", Zone A-27D, Columns M.7 and 18.9/20.0 As documented in the October 9, 1979 package, with the clarifi-cation that the water flow alarm associated with this water system will provide the necessary warning function in lieu of detection. An existing water flow alarm will be utilized for this alarm function. This water flow alarm also provides coverage for fire zone A-30 and A27B. All the fire zones associ-ated with the noted water flow alarms are in close proximity to each other and therefore no time is lost during fire brigade response.
9. Elevation 14'G", Zone A-24, Columns H.2/H.4 and 17.1/17.5 No change, as documented in the July 31, 1979 package.
10. Elevation 14'6", Zone A-24, Columns F.8/H.2 and 17.4 The new position agreed upon for this area is that detection will be provided for coverage at the cross-over areas. Also, Z2 cable trays involved in the cross-over will be completely enclosed. These trays will be enclosed from column line 16.6 to 17.7 (refer to Fire Hazard Analysis Report, Fire Zone Drawing 4 of 9). Enclosing the cable trays will be in lieu of fire rated barriers.

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