ML20003D945

Second Part 21 Rept Re Structural Inadequacy of Vlk Air Extractors Used in Ventilation Sys at Facilities.Caused by Supplier Design Deficiency on Extractors Larger than 16 Inches in Width.Final Rept by 810715

ML20003D945
Person / Time
Site:	Grand Gulf
Issue date:	03/12/1981
From:	Mcgaughy J MISSISSIPPI POWER & LIGHT CO.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
REF-PT21-81-382-000 PT21-81-382, PT21-81-382-000, NUDOCS 8104010576
Download: ML20003D945 (5)

Text

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P. O. B O X 16 4 0. J A C K S O N, MISSISSIPPI 39205 Yd[cNUol,jR March 12, 1981 Office of Inspection & Enforcement U. S. Nuclear Regulatory Commission Region II 101 Marietta Street, N.W.

-Suite 3100 Atlanta, Georgia 30303 Attention: Mr. J. P. O'Reilly, Director ,

SUBJECT:

Grand Gulf Nuclear Station Units 1 and 2 Docket Nos. 50-416/417 File 0260/15525/15526 PRD-80/63, Interim Report #2, VLK Air Extractors AECM-81/101 i

Reference:

AECM-80/285, 11/14/80 On October 15, 1981 Mississippi Power & Light Company notified Mr. J.

Rausch, of your office, of a Potentially Reportchle Deficiency (PRD) at the Grand Gulf Nuclear Station (GGNS) construction site. The deficiency concerns the structural inadequacy of VLK Air Extractors used in ventilation systems at GGNS.

Our investigation into this matter has not been completed. We have, however, determined this deficiency is reportable within the meaning of 10CFR50.55(e). The condition is not reportable under 10CFR21 because the items have not been offered to MP&L for acceptance. Attached is our interim report.

We expect to submit a final report by July 15, 1981.

Yours truly, p r J. P. McGaughy, Jr.

ATR:mt ATTACHMENT (

1 cc: See page 2 Member Middle South Utilities System

Mi~Z122iPPI POWER O LI2HT CZMPANY l

Mr. J. P. O'Reilly AECM-81/101 NRC Page 2  ;

cc: Mr. N. L. Stampley Mr. R. B. McGehee Mr. T. B. Conner Mr. Victor Stello, Director Office of Inspection & Enforcement U. S. Nuclear Regulatory Commission Washington, D.C. 20555 Mr. G. B. Taylor South Miss. Electric Power Association P. O. Box 1589 Hattiesburg, ME 39401

Attachment to AECM-81/101 Page 1 of 2 INTERIM REPORT #2 TO PRD-80/63 I. Description of Deficiency During installation and operation of supply registers in a non-safety related system, the VLK Air Extractors proved to be structurally inadequate. Specifically, when the extractors are installed to direct air flow vertically downward to air registers in the bottom of the duct, the weight of the assembly bears on a single vane, causing it to bend, thus allowing the vanes to shut, thereby closing off the air flow to the register. Similarly, in the horizontal application, the vane assemblies have a tendency to sag, especially for vane assemblies which are 18 inches or longer. Although the problem was identified on a non-safety -

related system, the same type of air extractors are used in safety-related systems.

It has been* deter =ined that the condition is reportable within the meaning of 10CFR50.55(e) because the ex:ractors are used in HVAC systems having safety related functions.

The supplier, Tuttle and Bailey, has reported this condition to the NRC, Washington, D.C. , as a Part 21 deficiency.

II. Approach to Resolution of the Problem The cause has been identified as a supplier design deficiency on extractors larger than 16 inches in width. The VLK worm gear cannot generate sufficient force to actuate the extractor. The problem is compounded by a flexing of the blade to which the actuator is attached causing sagging of the extractor.

The supplier is recommending corrective action as follows:

1. The installation of supporting straps designed to position and lock the extractor in place.

2. Rendering the mechanical operator inoperable and adjusting the air extractor by use of the supporting straps.

The adoption of the corrective action is dependent on the completion of seismic testing of the redesigned extractors and the subsequent review and evaluation of the test results.

III. Status of Froposed Resolution The redesigned extractors are undergoing seismic testing. Preliminary indications reveal that the test results will be satisfactory.

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Attachment to AECM-81/101 Page 2 of 2 IV. Reason Why a Final Report Will be Delayed Actions to preclude recurrence have not been established.

- Seismic testing has not been completed.

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