Iter cryoplant tanks ready for shipment

WNN 18 May 2016

The two biggest tanks for the Iter fusion reactor’s cryoplant have been completed in the Czech Republic. An exceptional convoy will be required to transport them to the Iter construction site in southern France.

The quench tanks measure 35 meters in length, 4.5 meters in diameter and weighing about 160 tonnes. They were produced by French gas technology company Air Liquide and its subcontractor Chart Ferox. Air Liquide was awarded a contract in May 2014 by Iter’s European domestic agency, Fusion for Energy (F4E), for the engineering, procurement, installation and testing of the tokamak reactor’s cryoplant. The contract was worth some €65 million ($74 million). Manufacture of the two tanks began at Chart Ferox’s facility in Decin in the Czech Republic last August and was completed recently.

ITER cryoplant tanks - 460 (ITER)

The cryoplant quench tanks (Image: Iter)

The cryoplant produces and distributes the cooling power needed to cool the fusion reactor’s magnets, thermal shields and cryopumps. The plasma within the Iter reactor is expected to reach 150 million °C. Cold helium will be circulated inside the reactor’s superconducting magnets to bring their temperature down to -269°C.

However, the magnets may occasionally experience a so-called ‘quench’. This is when they stop superconducting, become more resistant and increase in temperature by about 50°C. With reduced magnetic performance it is no longer possible to confine the plasma. As the temperature rises, the helium circulating through the cryogenic system starts to expand and is therefore diverted to the quench tanks where it is stored at -196°C.

Europe is providing Iter’s Liquid Nitrogen Plant and auxiliary systems that will cool down, process, store, transfer and recover the cryogenic fluids of the machine. Two nitrogen refrigerators will cool down Iter’s Liquid Helium Plant and two helium loop boxes. They will also supply the purification system, quench tanks, heaters and dryers with nitrogen in liquid or gaseous form. The two helium loops will cool down the thermal shields of the cryostat, vacuum vessel and regenerate the cryopumps. Some 8kg of helium will be processed per second. A helium purification system is planned to recover and clean helium gas from any impurities.

Construction work on Iter began in 2010 and is expected to come to an end in 2019. A commissioning phase will follow that will ensure all systems operate together and prepare the machine for the achievement of first plasma in November 2020. The facility is expected to reach full operation in 2027. Iter’s operational phase is expected to last for 20 years.