ML18038A034

Requests Extension from 851130 to End of 1986 Refueling Outage for Replacement of Limitorque Actuators on Emergency Condenser Isolation Valves.Replacement Actuators Unavailable During Spring 1984 Refueling.Fee Paid

ML18038A034
Person / Time
Site:	Nine Mile Point
Issue date:	06/07/1985
From:	Mangan C NIAGARA MOHAWK POWER CORP.
To:	Chilk S NRC OFFICE OF THE SECRETARY (SECY)
Shared Package
ML18038A033	List: ML18038A034
References
CON-#485-226 OL, NUDOCS 8508010010
Download: ML18038A034 (6)

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A' MOHAWK NIAGARA MOHAWK POWER CORPORATIO ERIE BOULEVARD WEST, SYRACUSE. N.Y. 13202/TELEPHONE t3I5) 474-I5II

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ma Mr. Samuel J. Chilk, Secretary rn U.S. Nuclear Regulatory Commission X.

1717 H. Street, N.W. C7 tD Washington, D.C. 20555 0 c5 Re: Nine Mile Point Unit- 1 EJl Docket No. 50-220 DPR-63

Dear Mr. Chilk:

This letter is being submitted in accordance with 10CFR50.49(g) to request an extension beyond November 30, 1985, which the Commission m'ay grant, for replacement of limitorque actuators on emergency condenser isolation valves.

Niagara Mohawk Power Corporation has been actively involved in the environmental qualification of electrical equipment at Nine Mile Point Unit 1 since 1979. Of the 623 items on the Master List, 617 were either qualified or replaced by March 31, 1985 as required by 10CFR50.49(g). More than 30 man years of labor and $ 6,000,000 have been expended to accomplish this. Also, was noted that our progress in reaching resolution of the equipment it qualification issue for Nine Mile Point Unit 1 ranked among the best according to the Systematic Assessment of Licensee Performance dated September 18, 1984. However, even in light of this extensive effort, there were six pieces of equipment for which qualification could not be completed by March 31, 1985 and for which an extension was granted by the Director of Nuclear Reactor Regulation until November 30, 1985. The current status of the equipment for which an extension was granted is as follows:

1. Shutdown Su ervisor Panels The testing program associated with the relays in the shutdown supervisory panels has been successfully completed. The. final report is currently being prepared by the testing laboratory and will be reviewed by our staff to ensure that documented evidence of qualification is complete. This wi 11 be accomplished prior to the end of the current extension to November 30, 1985.

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Page 2 2~ Limitor ue Valve Actuators on Emer enc Condenser Isolation Valves Replacement of the four actuators could not be completed during the spring 1984 refueling and maintenance outage since the replacement actuators were not available at that time. Removal of the old actuators and installation of the new actuators during operation presents a difficult task due to limited clearance in the area of the valves, operational problems associated with return of the system to service, and ALARA considerations. Installation problems include special rigging requirements, prevention of steam leakage during changeout, special ventilation because of high ambient temperatures (130 F/140 F), and personal safety considerations. Potential steam leakage creates a hazard for maintenance personnel. Water hammer could be experienced when returning the system to service in the hot condition. In addition, performing this replacement during plant operation would add an additional 5.2 manrem of exposure to the plant staff. Therefore, based on the above reasons, it is undesirable to replace the actuators during operation.

In order to replace the Limitorque actuators during a plant shutdown in accordance with the current extension, it would require a shutdown prior to November 30, 1985. The length of the outage required is estimated to be approximately eight days, in order to allow for the replacement of the actuators and provide sufficient cooldown time to eliminate any water hammer concerns. Replacement power costs for such an outage would be approximately $ 3,000,000.

Due to our concerns for intergranular stress corrosion cracking and Appendix J leak testing requirements, we have scheduled replacement of the emergency condenser piping system inside of the drywell, including the associated emergency condenser isolation valves, during the Spring 1986 refueling and maintenance outage. As part of this replacement activity, the four Limitorque valve actuators will be removed and reinstalled. Accordingly, replacement of the actuators prior to this shutdown would result in a duplication of replacement activities.

However, should we have a shutdown of sufficient dur ation prior to November 30, 1985, we will replace the actuator at that time.

It is with great reluctance but, based on the above safety considerations, and in accordance with 10CFR50.49(g), an extension, is requested for the limitorque actuators on the emergency condenser isolation valves. This extension would be from November 30, 1985 to the end of the 1986 refueling and maintenance outage which is currently scheduled to begin during March 1986.

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June 7, 1985 Page 3 Enclosed is a check in the amount of $ 150.00 as required by 10CFR170.12(c) for this extension request.

Sincerely, NIAGARA MOHAWK POWER CORPORATION C. V. Man n Vice President Nuclear Engineering and Licensing MGM:bd Enclosure

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