Nuclear Power Station Reactor Building Vent Stack

A nuclear power station in the United States had a reactor building vent stack suffering from deterioration and section loss due to corrosion of the structural steel framing supporting th

STRUCTURAL, a licensee of STRUCTURAL TECHNOLOGIES’ engineered products and services, was contracted to replace the metal paneling enclosing the vent stack, demolish the existing roof, cut out the existing deteriorated structural steel, install a completely new steel frame, install a new slab on metal deck roof, and install a waterproofing membrane on the new roof.

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Crane lifting new steel frame on roof of powerplant building

Overhead view of work area and roof frame

Roof support frame segments were assembled on the ground

Use of swing stage to transport crew members to work area eliminated the need for complex scaffolding

Knee braces placed on corner of steel frame

Project Overview

Fabrication and installation of new steel roof support frame on vent stack
Installation of waterproofing membrane on new roof
Innovative access plan minimizes use of scaffolding

A nuclear power station in the United States had a reactor building vent stack suffering from deterioration and section loss due to corrosion of the structural steel framing supporting the roof.

STRUCTURAL, a licensee of STRUCTURAL TECHNOLOGIES’ engineered products and services, was contracted to replace the metal paneling enclosing the vent stack, demolish the existing roof, cut out the existing deteriorated structural steel, install a completely new steel frame, install a new slab on metal deck roof, and install a waterproofing membrane on the new roof. Necessary precautions had to be taken as the original roof contained asbestos, lead and radioactive contaminated materials.

STRUCTURAL developed a plan where knee braces would be welded to the existing structural steel columns at each corner near the roof elevation, thus forming a group of supports for a large system scaffold platform.

This configuration allowed construction of the system scaffold to be performed on the ground instead of up in the air. A swing stage was used as an elevator to reach the scaffold on the roof and a manbasket hoisted via crane was used at the start of the project to setup the knee brace supports on the stack.

STRUCTURAL’s understanding of access and material handling allowed them to provide the owner with a cost-effective vertical access solution that reduced scaffold weight by 98 percent and eliminated the risk of collapse of surrounding roof structures.