Modelling research on the control scheme and control characteristic of a small gas-cooled reactor

The nuclear power system is one vital choice for interplanetary migration. The control rod and sliding reflector are the two most widely used control schemes with different characteristics for the space nuclear reactor. In the present paper, the control rod scheme and sliding reflector scheme of the 2.6 MWt reactor model are investigated and compared. According to the neutron physics analysis, the core arrangement and the control assembly motion scheme for the reactor start-up process are proposed, along with the reactivity insertion behavior. The results show that the reactivity insertion of the control rod scheme is $18.76, which is lower than the $26.01 of the sliding reflector scheme, and the weight of the former is 79.6 kg larger than the latter. However, the control rod scheme has significant advantages in core power flattening and control accuracy. Upon comprehensive consideration, the control rod scheme is recommended as the control scheme. The research results can lay the foundation for the control system layout scheme and control strategy design.