ML19326D550

Interim Deficiency Rept Re Liner Plate Bulge.Caused by Leaking Water Line in Exterior Concrete Wall.Corrective Action Not Yet Fully Determined

ML19326D550
Person / Time
Site:	Midland
Issue date:	03/30/1977
From:	Howell S CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
To:
Shared Package
ML19326D541	List: ML19326D545 ML19326D549 ML19326D550
References
HOWE-56-77, NUDOCS 8006180698
Download: ML19326D550 (2)

Text

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Consumcis

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J Power C0,mpa,y, General Offices: 2:2 West usenfoon Avenvo.. Jackson. Michsonn 49208 March 30, 1977 Hove-56-77 Mr J. G. Keppler, Regional Director -

Office of Inspection and Enforcement US Nuclear Regulatory Commission .

Region III .

. 799 Roosevelt Road .

Glen Ellyn, IL 60137 -

MIDLAND PLANT - UNIT NO. 2 LINER PLATE DOCKET NO. 50-330 .

This letter is an interim report in accordance with the requirements of 10 CFR 50: 55(e) dealing with the bulging of the Unit No. 2 liner plate at the Midland site.

Description of the Condition For Containment Unit 2, between azimuths 250 and 270 (about 20' vide), and from approximate elevation 593' to 696', the 1/h" liner plate bulged inward about 2' from the theoretical location and separated from the exterior vall.

Movement of this plate caused spalling of the concrete adjacent to the plate, general 2y about 3" in depth, except for some localized areas where spalling up to 10" vas noted. Movement of the liner plate also resulted in several small tears in the plate. The 1/2" thickened liner plate, located in an area of four penetrations covering about 6'-8" square, has also been bent. Initial obscr-vations indicate that this condition was caused by a leaking water line embedded in the exterior concrete vall at approximately azimuth 260 . The purpose of the

.vator line is to provide a water supply during construction.

Status To date, there has been a concerted effort to determine the extent of the damage to the liner plate and containment vall. Approximately 2,000 square feet of bulged liner plate and about 20 cubic yards of spalled concrete have been removed.

Examination- of the inside and outside concrete surfaces near the bulge indicate that the remaining concrete is structurally sound. Three holes have been core-

• i drilled and visually examined; the examination of the cores and holes show the concrete to be sound. Initial analysis and extuninations indicate the damane is confined to the bulged panel of the liner plate and the three inches of concretc

behind the liner. .

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r..2 r After the bulged plate and the spalled concrete were removed, ceveral tests of the embedded water line confirmed a leakage. Further study as to the cause of

.. this condition is in progress.

To date, the analysis and examinations of the liner plate and the adjacent concretc indicate no sit',nificant structural damace to the present containment integrity. The structural damar,e was limited to the snalled. concrete, which is a portion of an overall h2" thick exterior concrete vall. Analysis indicatcc that the reinforcement was not overstressed as a result of this condition.

Corrective Action As of this date, the corrective action has not been fully determined and the

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safety implications of the correction to the liner plate and concrete vall have not been determined. These subjects vill be discussed in a future report, either interim or final, which will ce sent on or before May 16, 1977 f JY Stephen H. Howell .

CC: Dr Ernst Volgenau (15) .

Director, Office of Inspection & Enforcement US Nuclear Regulatory Commission .

Washington, DC 205h5 Director, Office of Management Information and Program Control US Nuclear Regulatory Commission Washington,-DC 20545 e

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