Further refrigeration system for ESS

The European Spallation Source (ESS) project is a neutron research facility currently under construction outside Lund, Sweden, to provide insights into various materials. In May 2015, ESS placed an order with Linde Kryotechnik for the accelerator cryogenic plant (ACCP). Now, ESS turns again to Linde Kryotechnik – this time to build the Target Moderator Cryogenic Plant (TMCP).

The ESS accelerator will deliver a 5 MW proton beam to a spallation target at 2.0 GeV with a nominal current of 62.5 mA to generate fast neutrons. The cooling of the spallation target with liquid hydrogen circulating in the cryogenic moderator system (CMS) transforms these fast neutrons to slow neutrons which compose the useful radiation.

The liquid hydrogen itself is cooled by a helium refrigeration cycle, the target moderator cryogenic plant (TMCP) providing cooling capacity up to 30 kW at 15-20 K, with an exceptional turndown ratio higher than13. TMCP’s maximum cooling capacity of 30 kW will make it the world’s largest plant of its kind.

The TMCP project is challenging in many ways. The refrigeration capacity provided by the TMCP has to be precisely balanced instantaneously with the heat load of the CMS. In addition the TMCP has to meet highly dynamic requirements as the heat load ceases quickly in case the proton beam trips off. Furthermore transitions within the wide range of cooling capacity have to be achieved seamlessly.

The groundbreaking ceremony of the European Spallation Source took place September 2nd, 2014, the commissioning is scheduled for 2019 and operation at full load is expected for 2025.
ESS is publshing weekly updates of the site work.