Europe’s first cryoplant components ready for ITER

Europe is one of the ITER parties with a big stake in the field of cryogenics of the biggest fusion machine in history. The cryoplant can be described as a massive refrigerator which is going to generate extremely cold temperatures for some of the ITER components to achieve fusion power. For instance, to confine the super-hot plasma, expected to reach 150 million ˚C, the magnets will need to be cooled with liquid helium to reach a superconducting state at 4.5 K, close to absolute zero. In 2014 F4E signed a contract for the European share of components to ITER’s powerful cryogenic system with AirLiquide.

One of the facilities that F4E is responsible for, as part of its contribution to ITER’s cryogenic system, is the Liquid Nitrogen – LN₂ – plant. Basically, two nitrogen refrigerators with a power of 1 200 kW at 80 K will pre-cool ITER’s Liquid Helium Plants and cool down the 80 K helium loop boxes. In turn, the two 80 K helium loop boxes will thermally shield the cryostat, the vacuum vessel and the cryopumps of the fusion device. It is estimated that 8 kg of helium per second will be processed.

The F4E workforces are eagerly expecting the delivery of four turbines which will be inserted in the cold boxes of the LN₂ plant. Simon Saulquin, F4E’s Technical Officer overviewing the production of this equipment, explains that “this will be Europe’s first cryogenic component to be delivered and the first-ever for ITER’s cryogenic system. The good collaboration between F4E and its contractors helped us to meet the tight schedule and manufacture this vital component on time.” The role of the four turbines will be to generate vast amounts of cooling power for the ITER plant by expanding the gas previously processed by the nitrogen compressors. Two of the turbines will generate a cooling power of 500 KW and two others of 150 KW. The four turbines have been manufactured by Cryostar, one of AirLiquide’s subcontractors.

The two nitrogen compressors of the LN₂ plant, which have successfully gone through the Factory Acceptance Test (FAT), are expected to arrive to ITER by the end of September. Representatives from F4E and AirLiquide, Europe’s contractor for its share of cryogenics, have celebrated the successful completion of this manufacturing milestone. The tests were carried out in the premises of Atlas Copco Energas, Cologne, AirLiquide’s subcontractor for this specific component, responsible for the engineering, manufacturing and testing of the compressors. Manufacturing started in April 2015 and almost a year and a half later the two compressors weighing 85 tonnes each are ready to be transported to Cadarache. The compressors are 14.5 m long x 7.9 wide x 4.6m high and have a maximum working pressure of 37 bar. When they will be switched on they are expected to consume approximately 5 MW each in order to trigger off the cooling gas sequence of ITER’s Cryoplant.