ML19290F007

Forwards Recommendations Re Fire Protection Review Items 3.2.1 & 3.2.2.Protective Measures for Cable Spreading Room Crossovers & High Concentration Areas Should Be Accepted. Protection of Redundant Cable Trays Is Acceptable

ML19290F007
Person / Time
Site:	Millstone
Issue date:	12/20/1979
From:	Randy Hall BROOKHAVEN NATIONAL LABORATORY
To:	Ferguson R Office of Nuclear Reactor Regulation
References
NUDOCS 8003170443
Download: ML19290F007 (4)

Text

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BROOKHAVEN NATIONAL LABORATORY ASSOCIATED UNIVERSITIES, INC.

w a Upton, New York 11973 Department of Nuclear Energy (516) 345 2362 December 20, 1979 Mr. Robert L. Ferguson Plant Systems Branch U. S. Nuclear Regulatory Comission Washington, D. C. 20555

Subject:

Millstone - Unit 2, Fire Protection Review Items 3.2.1 and 3.2.2

Dear Bob:

Enclosed are our reco=endations for the subject items.

Very truly yours,

-vA obert E. Hall, Group Leader Reactor Engineering Analysis REH/EAM/sd Attachment cc: R. J. Cerbone R. E. Hall W. Y. Kato L. Derderian (w/ attach)

V. Panciera (w/ attach)

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MILLSTONE UNIT 2 FIRE PROTECTION REVIEW 3.2.1 Cable Spreading Area Section 3.2.1 of the S.E.R. indicates that the licensee will conduct an eval-untion to determine a suitable method to provide isolati on, separation or protection of redundant safety-related cables in the cable spreading area.

The following is a summary of the evaluation found in the licensee's letter dated July 31, 1979.

(a) The cable spreading room was divided into a number of areas by vary-ing degrees of raceway densities. In a number of areas fire retardant bar-riers will be installed to separate redundant non-essential cables. Some areas have no crossovers a-d redundant cables are widely separated.

(b) The main area between Column 15, 17.2/F8, 25 has the largest con-centration of cable raceways and those contain control, instrument, and power cables. With the high cable concentration and the lack of accessibility, re-11ance must be placed on detection and automatic extinguishment to mitigate a fire in this area.

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(c) The licensee will provide wet pipe automatic sprinkler protection in this 90 feet x 60 feet area of high cable concentration. The system will b,e designed for cable tray protection (i.e. , branch lines extending down from the ceiling with spray heads over the trays).

The new system proposed will be fed independently from the existing manual actuated deluge system.

The licensee letter dated October 9, 1979 restates the protection criteria (i.e. , cable tray protection to be installed instead of area protection). The licensee has elso committed to the removal of the combustible damming material and the installation of fire dampers in the concrete block wall separating Z1 and Z2 f acilities.

Based on a review of the letter dated July 31, 1979, the site visit on August 31, 1979, and a review of the letter dated October 9,1979, we recommend that the protection of the cable spreading room crossovers and high concentration areas be accepted.

3.2.2 Protection of Redundant Cable Trays Due to the lack of adequate cable separation, Section 3.2.2 of the S.E.R. re-quires the licensee to detennine the consequences of fire damage to redundant safety-related cables in the auxiliary building. If the consequences are un-acceptable, fire retardant coating, automatic sprinklers, fire barriers, fire detection, or a combination of protection will be provided to assure that fire damage will not result in a loss n? shutdown capability.

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An evaluation of cable routing in the auxiliary building was conducted by the licensee , and the results are submitted in a document with a cover letter dated July 31, 1979. Af ter review of the submittal certain areas remained in doubt. A site visit to specifically examine those areas in question was con-ducted on August 31, 1979. As a result of this visit certain modifications were documented in a submittal with a cover letter dated October 9,1979 and clarified in a letter dated November 21, 1979.

The modifications recommended for the various areas are as follows :

1) Elevation 45 feet Zone 1A Column ?.8/H.2 and 16.6/17/2.

Automatic sprinklers will be provided in the trays to protect crossovers in a balcony area. Ionization detectors will be provided at the ceiling. The sprinklers will be fed from an adjacent standpipe.

2) Elevation 45 feet Zone A-1 A Column F.8/H.2 and 17.2/18.4 Ionization detectors will be provided between Z1 and 22 trays for the length of the zone.

3) Elevation 25 feet Zone A-9 Charging Pump Area The general area ionization detectors will provide sufficient early notification to prevent involvement of the adjacent division. ,

4) Elevation -5 feet Zone A-18, Column F.3/F.8 and 18.9/19.6, Pipe Penetration Room The cable tray involved in the crossovers will be completely enclosed to prevent fire Lnpingement on the conduits above.

Ionization detectors will also be installed above the trays.

5) Elevation -5 feet Zone A-14, Column F.8/H. 2 and 18.1 General ionization detection will be provided in the zone with a number of detectors installed at the crossover.

Original design barrier will be installed above Z14FK10.

The clothing storage rack will be .elocated to reduce the combustible exposure to S/R cable trays.

6) Elevation 5 Zont A-14 Columns L.5/M.4 and 17.7 Ionization detectors and barriers will be installed to pro-tect the Z1 and Z2 crossover.

7) Elevation 5 Zone A-14 Columns M.4 and 17.8 Ionization detectors and a burrier between the trays and conduit will be installed to protect this crossover.

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8) Elevation 14 feet 6 inch, Zone A-27D, Column M.7 and 18.9/20.0 The protection of the crossover will consist of both area and tray automatic sprinklers. The area sprinklers will extend 15 feet into fire Zone A-27D. General area pro-tection will also be provided in the vicinity of the cross-Over.

9) Elevation 14 feet 6 inch Zone A.24 Column H.2/H.4 and 17.1/17.5 A general area detsction system with specific detectors lo-cated at the tray crossovers will be installed. Original design barriers will also be provided at these crossovers.

10) Elevation -14 f eet 6 inch Zone A-24 Column F.8/H.2 and 17.4 Ionization detectors will be provided over the croasovers and the trays involved will be totally enclosed from column line 16.6 to 17.7.

Based on a review of the evaluation, site visit and proposed modifications, we recommend that the cable separation criteria between redundant safety-related systems for the auxiliary building be eccepted.

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