ML19296C311

Final Deficiency Rept:Vertical Fire Dampers Supplied by Ruskin Mfg Co Fail to Close Completely.Caused by Disconnection of Damper Blade Closure Spring During Cycling. Dampers Will Be Modified Per Encl Drawings

ML19296C311
Person / Time
Site:	Wolf Creek, Callaway
Issue date:	02/12/1980
From:	BECHTEL GROUP, INC.
To:
Shared Package
ML19296C308	List: ML19296C306 ML19296C311
References
NUDOCS 8002250557
Download: ML19296C311 (5)

Text

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Final Report on Vertical Fire Danpers for the SRTPS Project Bechtel Power Corporation Gaithersburg, Maryland February 12, 1980 e

800225 559

TABLE OF CONTENTS 1.0 Introduction .

2.0 Description of Deficiency 3.0 Analysis of Safety Ieplications 4.0 Corrective Action 5.0 Conclusi.on P

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1.0 INTRODUCTION

In co=pliance with 10CFR50.55(e), this report is being issued due to failure of vertical fire dampers supplied to SNUPPS Project (Callaway ,

and Wolf Creek Jobsites) by Ruskin Manufacturing Cocpany, Grandview, FMssouri, to close cocpletely. The da=pers had been delivered te Union Electric's Callaway Unit No. 1 and Kansas Gas & Electric's Wolf Creek Jobsites.

2.0 DESCRIPTION

OF DEFICIENCY A nonconfor:ance report generated at Callaway Jobsite indicated failure of the lower end of the damper blade closure spring (flat ribbon coil type) to re=ain in place, resulting in incocplete closure of the vertical dampers. This failure was identified while the da=pers were being operationally cycled. One end of spring, on datpers designed for vertical installation, becomes disconnected during cycling. Release of the spring interferes with full closure of the damper.

A bracket at the lower end of the vertical da=pers holds the spring which is connected to the dacper blade. The brackets were originally designed to be installed as shown in the left hand sketch of Ruskin Manufacturing Co=pany Drawing No. 5398 (copy attached). To provide extra support for the bracket, Ruskin decided to tack weld the top edge of the bracket to the datper blade guide, as shown in the middle sketch on Ruskin Drawing No. 5398. The tack welding resulted in widening of the gap in the brackets and allowing the springs, in some instances, to slip out while they were recoiling during closure of the damper.

3.0 ANALYSIS OF SAFETY IMPLICATIONS Fire da=pers are provided for all HVAC system penetrations of fire rated walls to prevent spread of a fire through the ductwork froc one area of the plant to another. Many of the fire rated walls provide separation of redundant safe shutdown equipment. Approxicately 85 vertical fire dampers are used in the Auxiliary Building, 22 in the Fuel Building, 117 in the Control Building, and 2 in the Reactor Building in each of the SNUPPS Units.

Failure of a damper to fully close during a fire situation could potentially per=it the fire to spread fro: one fire area to another

. area containing safety related equipment.

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4.0 CORRECTIVE ACTION A #6 screw using a washer, star lockwasher, and hex nut, will be installed in the narrow portion of the spring slot, as shown in the ,

Ruskin Manufacturing Company Drawing No. 5398. The vertical fire dampers for Callaway Jobsite have been returned to Ruskin for necessary modification. Fire dampers for Wolf Creek, not yet installed, will either be returned to Ruskin for the necessary modification or else modified on site. Dampers already installed at Wolf Creek will be modified at the jobsite. Vertical fire dampers, not yet shipped to SNUPPS Units, will be modified prior to delivery. All vertical fire daepers modified per this report will be operationally cycled, prior to or during installation, to confirm acceptability.

This deficiency has been . sported to the NRC by Ruskin Manufacturing Company as a 10CFR Part 21 defect. The Ruskin report has provided the necessary generic information, required by 10CFR Part 21 reporting requirements.

%.0 CONCLUSION Af ter modification, all vertical fire da=pers will close completely, as intended, and will prevent spread of fire from one fire area to another area containing safety related equipment.

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