ML20128E081

Forwards Detailed Description & Safety Evaluation of Activities Re Thermal Shield Insp & Repair During 1984 Outage.Neutron Noise & Loose Parts Monitoring Considered in Evaluation

ML20128E081
Person / Time
Site:	Maine Yankee
Issue date:	06/19/1985
From:	Butcher E Office of Nuclear Reactor Regulation
To:	Randazza J Maine Yankee
Shared Package
ML20128E084	List: ML20128E081 ML20128E112
References
NUDOCS 8507050253
Download: ML20128E081 (1)

Text

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o June 19, 1985 Docket No. 50-309 DISTRIBUTION:

.N PSears Mr. J. B. Randazza NRC'PDR"' PKreutzer Executive Vice President Local PDR ACRS +10 Maine Yankee Atomic Power Company ORB #3 Rdg Gray File

83 Edison Drive HThompson 2 Augusta, Maine 04336 OELD

EJordan

Dear Mr. Randazza:

BGrimes JPartlow

SUBJECT:

THERMAL SHIELD INSPECTION AND REPAIR - NEUTRON NOISE AND LOOSE PARTS MONITORING

Reference:

Letter-Report, G. D. Whittier to J. R. Miller, "1984 Refueling Outage Thermal Shield Repair",

dated September 14, 1984 We have reviewed the referenced report on Maine Yankee thermal shield repairs during the 1984 outage and thermal shield operation and surveil-lance.

Maine Yankee was the first Combustion Engineering (CE) plant to encounter distress with the thermal shield to core barrel support system. It was initially believed that the problem consisted solely of three missing upper positioning pins. The problem was evaluated and operation continued with no repairs performed.

In light of later much more severe problems in this area in other CE plants, you decided to perform more thorough examinations and repairs, if necessary.

The examinations disclosed no thermal shield or core barrel cracking as had been observed at other CE plants but a number of upper and lower positioning pins were found to be not bearing upon the core barrel as had been designed.

Repairs were performed and improvements made in noise monitoring, as well as a commitment made to reduce the next inspection interval for the core barrel i assembly. A detailed description of the activities involved and the staff's evaluation is enclosed.

This evaluation is for your information. No response is required, j

Sincerely, l

Orfinal signed by:

Edward J. Butcher, Acting Chief Operating Reactors Branch #3 j Division of Licensing

Enclosure:

As stated See next page G'%% _ /?

ORB #3 0$#3:DL gDb ORy}kher

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