IHEP scientists announced that important progress had been made on the R&D of the cryogenic accumulator for the China Spallation Neutron Source (CSNS) Project.

As one of the key devices of the CSNS cryogenic hydrogen system, the cryogenic accumulator is used to mitigate the pressure swing caused by the dynamic heat load from the neutron moderation, and to protect the cryogenic hydrogen system and the moderators from any mechanical damages.

A series of experiments were carried out at room temperature and liquid nitrogen temperature to test the function of the accumulator before installing it into the hydrogen cold box. The results proved that the accumulator could regulate pressure well, and when a sudden dynamic heat load of 700 W was added to the cryogenic hydrogen loop, a pressure variation of only 11.53 kPa occured, which was much better than the designed requirement of 50 kPa.

The accumulator is widely adopted in the spallation neutron sources in operation around the world. By comparing with the operating principles of the accumulator in SNS and JSNS, the CSNS cryogenic group has developed a unique scheme with two welded bellowses and a series of technical improvements have been made to guarantee the pressure regulating performance of the accumulator.

 Cryogenic experiment

 Monitor interface

 Some experimental results