ITER will require a massive cryogenic system to cool down magnets and other components so as to operate properly. Eight cryopumps will ensure the correct vacuum conditions inside the vacuum vessel and the cryostat, and will be connected to this refrigeration system through cold valve boxes (CVBs).
A total of eight CVBs – one for each cryopump – will distribute helium through the different parts of the cryopumps. F4E, in collaboration with its contractor Research Instruments (RI) and subcontractor Cryoworld, has already completed half of the production. Four CVBs have been manufactured, passed the required factory acceptance tests and have been shipped to undergo further works.
The CVBs are 4-tonne pieces of equipment measuring more than 3 m in height and around 2 m in diameter. They will deal with cryogenic fluids in a wide range of temperatures: from super-cold -269 °C up to fairly hot 230 °C. Also, components will withstand a hostile environment with high magnetic fields and radiation. Integrating all the valves, pipes and accessories together in a rather limited space is another constraint. Michael Pekeler, RI director of superconducting RF, fusion and special manufacturing projects, elaborates on this. “Our team at RI and our partners at Cryoworld are very satisfied to see the valve boxes for F4E becoming reality. Their design was quite challenging, as the high neutron flux at the location of installation did not allow usage of almost any off the shelf components. We are grateful for the excellent collaboration with F4E and ITER experts throughout the design and manufacturing phase of this equipment.”
Lluís Mora, F4E Cryoplant and Fuel Cycle technical responsible officer, gives us more insight into the CVBs. “They are equipped with 25 cryogenic valves, relief systems, pressure and temperature sensors that are specifically selected to work under the harsh ITER environment. Component selection, manufacturing, assembly and testing is done following high quality standards. All development is followed thoroughly by nuclear safety officers from F4E and ITER Organization.”
The contract to prepare the final design and manufacturing of these systems was awarded in 2018. The final design review meeting was held in October 2020, during a very restrictive time for meetings imposed by the COVID-19 pandemic. Now that Cryoworld has finished half of the CVBs production, Research instruments will complete their manufacturing by installing the electrical wiring, pneumatic connections, and by completing the factory acceptance testing. After that, the CVBs will be ready for delivery to the ITER Organization, which is expected to take place towards the end of the year.