LOW LOSS FLEXIBLE CRYOGENIC TRANSFER LINES FOR JET

At JET, a large toroidal fusion experiment, long flexible transferlines (up to 80 m) will be used to supply liquid nitrogen and helium from a central distribution board to series of cryogenic users. The main virtue of such lines is the fact that they can be completely tested at the manufacturer's premises, and that the requirements for installation, test and commissioning are minimum. For the cryogenic helium line a low loss flexible configuration was developed and tested. The performance data obtained showed heat losses of less than 5 mW/m for the liquid He-go line and less than 500 mW/m for the boil off flow.