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Kinectrics examines the effects of compressed air on feeder ice plugs by conducting tests on feeder mock-ups.

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Freeze Jackets for Feeder Maintenance

Expanded capabilities for feeder maintenance using new freeze jacket design

The temporary blockage of water-filled feeder pipes by the formation of internal freeze (or ice) plugs has been routinely employed for many years in the nuclear industry as part of feeder maintenance activities. Ice plugging is achieved by flowing liquid nitrogen through a metal jacket wrapped around a segment of feeder pipe.

Current freeze jacket designs have limited capability in terms of location of installation. Traditionally, the size of freeze jackets has required a significant amount of clearance between pipes. In addition, jackets have typically been capable of operation only on vertical segments of pipe.

Kinectrics, a leader in this technology for the nuclear industry, has developed a freeze jacket design capable of being installed both horizontally and vertically and, in areas with a clearance as low as 2 inches between adjacent pipes.

Kinectrics’ new freeze jackets are installed using integrated remote tooling to enable placement in pipes that are out of arms’ reach.

Freeze jackets have been developed by Kinectrics for various feeder pipe sizes ranging from 1.5 inch to 3.5 inches (nominal) in diameter. The use of aluminum as the main jacket material keeps weight to a minimum for improved ease of handling.

A companion pipe temperature monitoring system has been developed along with the freeze jackets. Thermocouples are attached directly to the jacket, to be used with cabling to allow pipe temperature monitoring at a panel on the reactor vault floor. The panel has an Ethernet interface to enable remote monitoring and logging.

The Kinectrics freeze jacket design has been fully tested and a full set of production units has been successfully deployed to an operating CANDU site.