ML17331A681

Submits Interim Rept on Corrective Actions Taken in Response to IE Bulletin 80-11, Masonry Wall Design. Mods on 39 Walls Will Be Completed by 811001.Final Rept Will Be Forwarded by 811031

ML17331A681
Person / Time
Site:	Cook
Issue date:	03/20/1981
From:	Hunter R INDIANA MICHIGAN POWER CO. (FORMERLY INDIANA & MICHIG
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
AEP:NRC:0418B, AEP:NRC:418B, IEB-80-11, NUDOCS 8104030543
Download: ML17331A681 (4)

Text

INDIANA L MICHIGAN ELECTRIC COMPANY P. O. BOX 18 BOWLING GREEN STATION NEW YORK, N. Y. 10004 March 20, 1981 AEP:NRC:0418B Donald C. Cook Nuclear Plant Unit Nos. 1 and 2 ApR 0 1198'I I Docket Nos. 50-315 and 50-316 Msh lQCLtAR REGNATOC License Nos. DPR-58 and DPR-74 gOhNISSON

/ 'P Mr. James G. Keppler, Director 4h U. S. Nuclear Regulatory Commission Office of Inspection and Enforcement Region III 799 Roosevelt Road Glen Ellyn, Illinois 60137

Reference:

1) NRC IE Bulletin 80-11 dated May 8, 1980

2) Letter AEP:NRC:0418 dated July 10, 1980

3) Letter AEP:NRC:0418A dated January 14, 1981

Dear Mr. Keppler:

This letter is an interim report on the activities being carried out at the Donald C. Cook Nuclear Plant to address the concerns of Reference (1). In References (2) and (3) we reported the status of the evaluation which was partially completed at that time. This letter reports the results of our plant survey and the status of the wall evaluations.

As reported earlier, one hundred and thirty (130) masonry walls at the Cook Plant fall under the scope of the bulletin. We have completed the plant survey of all the accessible walls. Eighteen (18) walls were inaccessible during power operation (on one face of the wall) and will be surveyed during the current Unit 2 refueling outage, and the next refueling outage for Unit l.

The results of our field walk and design evaluation are:

a) Number of walls recently designed which meet Reference (1) Criteria.. ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 6 810408 0 QgU MAR 2 5 >98)

E I

ll k

.a)

II f~l~ i' (

• Piaa'I df

~,u

Mr. James G. Keppler AEP: NRC: 0418B b) Number of walls that can withstand the seismic forces, and no pipe break loads exist...........82 c) Number of walls that require modifications for seismic forces, and no pipe break loads exist...........................................39 d) Number of walls that do not require modification for seismic forces and are under evaluation for pipe break loads... ... . . . . . . . 3 TOTAL 130 The modification of the 39 walls noted above will commence shortly and we expect to complete the work by October 1, 1981. Some of the modifi-cations can be performed during plant operation but some require a refueling outage. By October 1, both units will have been out of service for refueling outages.

The 39 walls requiring modification are not load bearing walls; they are for radiation shielding and area separation purposes. Since these walls are built for specific local conditions and are not part of the structural system, the failure of any of these walls in the unlikely event of a design basis earthquake does not affect the integrity of the building. Further, it is only under the most conservative assumptions that collapse of these walls could possibly damage safety-related equipment at the Plant. For example, we have assumed an affected area equal to the area of the wall, with no credit for any intervening equipment or inherent resistance of the equipment itself to wall debris. Considering the exceedingly low probability of occurrence of a DBE, and that the necessary modifications will soon be implemented, continued plant operation is warranted until the completion of such modifi-cations.

The final report of the description of the design modifications and plant changes will be submitted by October 31, 1981. We do not intend to submit another interim report by May 1, 1981 as previously noted in reference (3)

Very truly yours,

. Hunter Vice President cc: R. C. Callen G. Charnoff John E. Dolan - Columbus R. W. Jurgensen D. V. Shaller - Bridgman NRC Resident Inspector 8 Cook Plant

4'I