Specifically, the company was commissioned to design a method of safely removing one metre lengths of ducting without contaminated particles becoming airborne, to carry out on-site trials and subsequently supply application equipment and sealants which Sellafield operatives would be trained to use.
The method devised by Steve Vick involved using the company’s patented FOAMBAG™ technique, whereby a specially tailored fabric bag is inserted into a void and injected with an expanding resin foam. For the Sellafield project, to prevent the breach in containment of the glovebox extract duct, it was decided to drill into the duct through a valve system and insert a FOAMBAG™ into it via an air tight gland system. A calculated quantity of closed-cell expanding polyurethane foam was then injected into the bag using a Steve Vick applicator system. During expansion, some of the foam is designed to seep through the semi-porous fabric bag to adhere to the walls of the duct making an airtight seal.
The application system was initially designed so that foam injection could take place from a remote position at least five metres away from the ducts, thus reducing the operative’s exposure time. However, after the technique was demonstrated to engineers at Sellafield it became clear that the method was so quick and efficient that exposure times were no longer an issue. This allowed the quantities of foam used to be reduced, further speeding up the process and reducing wastage.
Once the foam in the FOAMBAGs had fully expanded and cured, an operative was then able to cut through the ducts at the point of injection. The foam provided an airtight seal at both ends of the severed duct, making it safe to remove and transport the pipe.
Asked for comments on the project, Tony Cueto, Sellafield Ltd project engineer said, “After only four weeks of research and development, Steve Vick were able to demonstrate a working system to us at Sellafield. It took only one day to fully train and assess our operatives at an off-site location in Cumbria and this actual scope of the project was completed in just two weeks with no problems, radiological and conventional, occurring. We were impressed with the speed, support and outcome of the Steve Vick team’s work.”
Thirty years’ experience
Steve Vick International has been at the forefront of sealant engineering in the safety critical gas industry for more than 30 years and has been employed by various bodies in the nuclear decommissioning sector to provide solutions to the problems associated with removing pipes and ducts and sealing pressurised underwater pipelines.
In recent years the company has committed more resources to this area with the aim of increasing its share of contracts. One of the key benefits of the Steve Vick sealing technique is that the foam injection process can be carried out from up to 50 metres away, making it highly appropriate in contaminated, or underwater situations. Also, as the cured foam is extremely lightweight, the filled duct or pipe can be easily removed and disposed of.
Steve Vick has exhibited at a number of the Nu-Tech Nuclear exhibitions which have resulted in several different projects, some of which are still on-going.
Date published – 4th November 2011