Cyril W Bishop Engineering Services Ltd. Pipefreezing Images 3

 

Pipefreezing has been widely used in the nuclear industry, where the benefits of not having to drain down pipe contents that are (or could be) radioactive are immense.  These pictures are from the secondary reactor vessel cooling system at Hunterston power station in Scotland. Because of the safety issues involved, heat-flux monitoring was used on all freezes.  Click on the pictures for a larger version.

 

	A Bishop Engineering technician tends two freezes to enable modifications to the secondary cooling circuit. New pipework on the adjacent circuit is visible in the foreground. Because of the enclosed nature of the pipework tunnel, considerable effort was required to ensure that nitrogen vapour was removed, and a continuous supply of fresh air was pumped into the tunnel. See the Safety page.
	Looking into the cut end of a freeze-isolated pipe: the ice plug is clearly visible. This picture was taken at a full-scale trial of the operation depicted above.
	Scottish Nuclear engineers were concerned that in-situ welds were not exposed to extreme low temperatures, so trace heating was used to keep a 1" branch line warm: the lack of frost on the branch indicates that it is above 0oC.

 

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