Liquid nitrogen plant getting ready to make ITER cooler

White smoke coming out, confirming the presence of liquid nitrogen inside the storage tank of the ITER Cryoplant, Cadarache, France, April 2022. © ITER Organization

The ITER Cryoplant, the massive refrigerator that will keep magnets and many other systems at low temperature, is getting closer to completion. After the commissioning of the helium storage tanks, which are now filled with this gas, the F4E-ITER Organization Cryogenics Project Team is preparing the distribution line system to operate, in order to supply helium to all the other parts of the cryoplant. At the same time, commissioning of the liquid nitrogen (LN2) plant is ongoing.

A 26 m tall cylinder with a storage capacity of 300 m3 is the protagonist. After being cleaned and purged to remove impurities, the tank was cooled and filled up to 80 % of its capacity, which is the usual working level. For this task, twelve Air Liquide road trailers of 25 m3 each were unloaded into the tank. Nitrogen, like helium, will be used by other systems in the cryoplant and parts of the ITER machine. Liquid nitrogen is taken from the storage and is pressurised by a system of pumps, to be later warmed up to room temperature by heaters, to be subsequently directed to the different systems. Pumps and heaters are the next pieces of equipment to be commissioned.

Filling the storage tank with liquid nitrogen from a 25 m3 road trailer in Cadarache, France, April 2022.
Filling the storage tank with liquid nitrogen from a 25 m3 road trailer in Cadarache, France, April 2022. © F4E

“The past few months allowed the integrated project team to arrange the work in the best way to use efficiently resources and to minimise risks. In the coming weeks, we will have to operate much more delicate rotating machinery and I am sure the team will be well prepared for this challenge. Thanks to the team’s dedication and effort, we will reach our goals and deliver the LN2 cryoplant and auxiliary systems,” explains Grigory Kouzmenko, F4E Project Manager.

Liquid nitrogen has a number of uses in ITER: it will help cooling down helium in the 80 K loops and liquid helium plant cold boxes, making it ready to use for other systems such as cryopumps and superconducting magnets. Liquid nitrogen will also be used in the gaseous helium purification systems, or in the gaseous nitrogen generator. This piece of equipment, which takes air, liquefies it and separates the nitrogen from it, is just starting its own commissioning. Getting ready the nitrogen and helium facilities enables the commissioning of the remaining equipment. Step by step, we are getting closer to the complete commissioning of the ITER Cryoplant.