ML20212M885

Safety Evaluation Supporting Exemption from 10CFR50,App R to Relocate Redundant Shutdown Sys within Switchgear Room in Lieu of Providing Alternate Shutdown Capability

ML20212M885
Person / Time
Site:	Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png
Issue date:	08/25/1986
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML20212M877	List: ML20212M876 ML20212M879 ML20212M881 ML20212M885
References
NUDOCS 8608270361
Download: ML20212M885 (3)

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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATIVE TO APPENDIX R EXEMPTION REQUESTED FOR HADDAM NECK PLANT DOCKET NO. 50-113

1.0 INTRODUCTION

t In a July 16, 1982 letter, CYAPC0 requested an exemption from Section l

III.G.2 and proposed to relocate redundant shutdown systems within the switchgear room in lieu of providing alternate shutdown capability.

CYAPC0 indicated, at that time, that the cost of alternate shutdown capability would be prohibitive.

In a draft safety evaluation dated November 3, 1982, the staff accepted CYAPC0 proposals for this area.

These modifications were to be completed before startup from the 1986 outage which commenced on January 4, 1996.

In a final safety evaluation dated November 14, 1984, the staff granted eight exemptions from the requirements of Appendix R. including an exemption pertaining to the proposed switchgear room modification.

In a letter dated August 15,1985, CYAPC0 indicated that a request for schedular relief would be' forthcoming for the proposed switchgear room modifications which had been approved in the staff's 1982 and 1984 safety evaluations. By letter dated March 7, 1986. CYAPC0 requested a schedularexemptionfrom10CFR50.48cunder10CFR50.12(a)(2)(v)to accommodate an alternative design for the switchgear room and related plant areas (fire areas A-1,' R-1, R-3 S-2, S-3, and T-1) which would achieve the separation of redundant shutdown divisions required for fire protection and would also provide safety improvements for other unrelated events.

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2.0 EVALUATION By letter dated March 7,1986, CYAPC0 has indicated that all of the plant modifications to comply with the requiremants of 10 CFR 50, Appendix R are complete, exc'ept for separation of the electrical divisions in the switchgear room and related plant areas, and their pending September 16, 1985 exemption requests.

Further, CYAPC0 requested a schedular exemption from 10 CFR 50.48(c) under10CFR50.12(a)(2)(v)toaccommodateanalternativedesignfor the switchgear room which would achieve the separation of redundant shutdown divisions required for fire protection and woulo also provide safety improvements for other unrelated events. Rather than relocating safe shutdown equipment within the existing switch-gear room, as previously proposed, a new building wouid be constructed containing a switchgear room with one shutdown division.

The planning, construction and testing associated with alternative proposal would require schedular relief until start-up following the currently planned 1989 outage.

This schedular extension would also apply to related plant locations which contain shutdown-related cables that are impacted by the newly proposed switchgear room modifications.

While the newly proposed approach for the switchgear room would not be completed until the 1989 refueling outage, the conceptual design would provide a substantial improvement in fire pro'.ection capability over that associated with the exemption in the staff's November 1984 safety evaluation. Moreover, this conceptual design could provide a substantial improvement in safety with respect to tornado missiles, internal missiles (local motor-generators), standby power systems, and high energy pipe break effects.

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.. l In the present configuration, a fire in any one of the affected areas (A-1A, A-1B, A-1C, A-ID, R-1, R-3, S-2, S-3 and T-1) could potentially result in a loss of safe shutdown capability. The licensee's proposed modificatioh would reroute one electrical division so as to eliminate this vulnerability.

In the interim, the licensee has proposed I

compensatory measures, in the form of a continuous (i.e., twenty minute I

rounds) fire patrol in the affected areas. This fire patrol, in confunction with the fire detection and suppression systems in the switchgear room and related areas.. provide reasonable assurance that any fire would be detected and extinguished before redundant divisions are affected. The existing fire protection for this area consists of a smoke detection system, an automatic Halon fire extinguishing system, manual hose stations, and portable fire extinguishers. On this basis, the staff concludes that the existing lack of divisional separation will not present an undue risk to public health and safety in the intervening time.

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3.0 CONCLUSION

The licensee has completed most of the plant modifications required to comply with Appendix R to 10 CFR 50. While the lack of separation in the switchgear room and related areas represent a significant fire vulnerability, the licensee has installed the fire protection systems discussed above and has conuiltted to additional compensatory measures (continuous fire patrol) which provide reasonable assurance that this vulnerability will not present an undue risk to the public health and safety until the proposed plant modifications are complete.

The proposed plant modifications represent both a significant improve-ment in fire protection capability, over that previously approved by the staff, and a significant improvement in overall plant safety for other events.

In addition, the licensee's proposed implementation schedule for the proposed modifications appears to be the best effort possible in relation to the projected refueling schedules during which required plant modificatiuns must be performed.

Dated: August 25,1986