ML19329G031

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Responds to Re NRC Insps of Reactor Vessel Anchor Bolts.Bolts Are Susceptible to Cracks in Thread Area Due to Original Bolt Specs,Selection of Matls & Method of Heat Treating.Nrc Reviewing Revised Design to Determine Adequacy
ML19329G031
Person / Time
Site: Midland
Issue date: 06/23/1980
From: Strasma J
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
To: Marshall W
MAPLETON INTERVENORS
References
NUDOCS 8007110488
Download: ML19329G031 (1)


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. u....30-393 Mr. Wendell H.- Marshall President, Mapleton Intervenors Route 10 Midland, MI 48640

Dear Mr. Marshall,

In respense to your June 5,1980, letter to Mr. Keppler, we are providing the following information:

1.

Several inspections have been conducted by NRC inspectors relative to the Midland Unit 1 Reactor Vessel anchor bolts.

These inspections were conducted at the Midland site, Consumers Power Corporate Offices, Bechtel's Ann Arbor Offices, and at several vendor locations.

The inspectors concluded that due to the or161nal bolt specifications, selection of materials and method of heat treating, the anchor bolts are susceptable to cracks in the thread area. The NRC has concluded that the bolts are unacceptable for use with the high tensile forces of the original design.

2.

Consumers Power is currently reviewing various options to resolve the bolt problem.

One of these options it has reviewed with the NRC is to loosen the tension on the bolts and add additiot.al bracing near the top of the reactor vessel. Any change fro =

the original design will require the review and approval of the NRC.

This matter is now being reviewed by the licensing branch of the NRC to determine if the revised design would be adequate both for normal operation and during any potential accident conditions.

The documents related to the bolt problem are available for public exa=ination as part of the NRC's document collection at the Midland, Michigan, Public Library.

If I can be of further assistance, please let ce know.

S ncerely yours, r

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Jan Strasca Public Affairs Officer cc:

V. Stello, Director, IE Local PDR PDR W. J. Oldstead, OELD 8007110% g