A Canadian Nuclear power station engaged with Steve Vick International to design and supply an effective method for sealing and decommissioning an active pipeline. Historically, this type of operation could only be carried out during scheduled reactor shut downs. The devised SVI solution allowed for the operation to take place while the reactor, and therefore, the pipeline was still active and in use.
The solution was to use a combination of SVI techniques for pipeline decommissioning. Entry to the live pipe was achieved using lightweight, small and easy to use hot-tapping saddles and ‘Under Pressure Drill’.
The internal flow-stopping or sealing operation was achieved by introducing an SVI Foambag into the pipe via the new hot-tapping saddle connection. This method ensured that the operation could be carried out without any containment breaches.
The SVI FOAMBAG™ technique was initially developed over 30 years ago for the gas distribution industry. It was found to be far superior to air bag flow-stopping methods for a number of reasons, introduction into a pipe could be carried out in live situations, the sealant used in the Foambag was excellent at encapsulating any loose debris or contamination within the pipe and the Foambag adheres to the internal wall of the pipe.
The combination of all of these advantages ensures that a Foambag can seal inside pipes even when there is a relatively high level of pipe degradation or loose contaminates and debris.
The Foambag system meets the UK gas industry technical standard T/SP/E/59 and has become a trusted method of flow-stopping sections of live gas mains. The system has been further developed for use within the nuclear and off-shore oil decommissioning sectors. Succsessful deployment of SVI systems has been carried out at various sites including Sellafield and the Dunlin Alfa off-shore oil platform.
The technique is suitable for non-standard diameters, materials and shapes and can be used on tapers and bends as well as on vertical pipe.
A technician at the power station said:
“Your FOAMBAG™ solution was so effective and easy to deploy it was amazing, I actually have not one negative thing to say about it. The product was as promised and worked as described and allowed us to abandon the pipeline without the need to shut the reactor which saved us a large amount of additional work.”