ML20207J537

Concludes That Licensee 861124 Request for Deferral of Implementation Date for Switchgear Room Halon Sys Mods to Date No Later than Completion of 1987 Refueling Outage Acceptable

ML20207J537
Person / Time
Site:	Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png
Issue date:	12/15/1986
From:	Harold Denton Office of Nuclear Reactor Regulation
To:	Mroczka E YANKEE ATOMIC ELECTRIC CO.
References
NUDOCS 8701080507
Download: ML20207J537 (2)

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'...../ December 15, 1986 Docket No. 50-213 Mr. Edward J. Mroczka, Senior Vice President Nuclear Engineering and Operations Connecticut Yankee Atomic Power Company Post Office Box 270 Hartford, Connecticut 06141-0270

SUBJECT:

DEFERRAL 0F COMPLETION DATE FOR SWITCHGEAR ROOM HALON SYSTEM FIRE PROTECTION MODIFICATIONS By letter dated August 25, 1986, the NRC granted the Connecticut Yankee Atomic Power Company (CYAPCo) an exemption from the schedular requirements of 10 CFR 50.48 for the Haddam Neck Plant. This exemption was granted con-tingent on, among other things, the implementation of the comitments in the July 3,1986 CYAPCo letter by January 1,1987. By letter dated November 24, 1986, CYAPCo requested NRC approval to defer completion of one comitment involving modifications to the switchgear room Halon system until an outage of at least 8 weeks duration after January 1,1987, or until the 1987 refueling outage.

CYAPCo identified three specific concerns regarding modification of the switch-gear room Halon system while the plant is operating. CYAPCo concluded that there was a significant potential for damage to sensitive safety-related equip-ment such as motor control center 5 (MCC-5), feederbreakers to MCC-5 and the semi-vital power-regulating transformers. MCC-5 is the only safety-related motor con-trol center which automatically receives power upon a loss of normal power and is not single-failure protected. CYAPCo also concluded that there was high poten-tial for dust or debris to become lodged in a relay contact or armature which might result in an undetectable relay failure. This failure mode actually occurred at the Haddam Neck Plant following plant modifications in the control room performed during the most recent outage. Lastly, CYAPCo concluded that work on the Halon system would require the system to be disabled. In addition, a large amount of combustibles, such as lumber, rags, solvents, etc., would be brought into the switchgear room and there is also the potential that some welding would need to be performed. CYAPCo concluded that the introduction of additional combustible materials and ignition sources into the switchgear room g10%h $$ 3 F

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Edward J. Mroczka with the installed Halon system disabled were undesirable conditions for power operation with potential adverse safety implications.

The staff has reviewed the information provided by CYAPCo and concurs with the

, CYAPCo assessment. With the deferral of the implementation date for system modification, the staff concludes that adequate fire protection of the switch-gear room will still be provided by the currently installed and operable Halon

system, the existing fire detection system and by the current fire watches (one i full-time continuous and one roving watch) supplemented by manual fire fighting equipment in the area.

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Based on the above and in accordance with the provisions of the schedular exemp-tion, the staff concludes that deferral of the implementation date for the switch-gear room modifications to a date no later than the completion of the 1987 refueling

. outage is acceptable.

Sincerely, T

Harold R. Denton, Director i

Office of Nuclear Reactor Regulation 4

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