Development of the control system for the ESS Cryogenic Moderator System

Abstract A Cryogenic Moderator System (CMS) was designed to circulate subcooled liquid hydrogen at a temperature of 17 K and a pressure of 1.0 MPa to remove the nuclear heating at the moderators, which is estimated to be 6.7 kW for a 5-MW proton beam power. The CMS is cooled via a plate-fin type heat exchanger by a large-scale 20 K helium refrigeration system, referred to as the Target Moderator Cryoplant (TMCP) with a cooling capacity of 30.3 kW at 15 K. The CMS Basic Process Control System (BPCS) is responsible of controlling a wide array of equipment, so different device types, generic software control blocks with a wide range of features and Operator Interface elements developed. Control system hardware structure and network configuration were designed with modularity and availability in mind. This paper presents a detailed description of the CMS BPCS architecture and the interaction between the TMCP and the CMS.