Simulation Study of Nuclear Heating Reactor Control Method in Slight Boiling Operation Mode

Abstract Nuclear Heating Reactors (NHRs) could achieve multi-purpose target including heating and seawater desalination without emission of greenhouse gases. Institute of Nuclear and new Energy Technology (INET) have designed two operation modes for NHRs: pressurized mode and slight boiling mode. The former shows a higher level of maturity, while the latter guarantees better economic outcomes but still lacks comprehensive testing and analysis. Previous researches on operation of NHR slight boiling mode mainly concentrate on avoiding instabilities during reactor start-up process, while the power adjustment process is also important but seldom researched. NHR-200II/S is designed to obtain the slight boiling operation capability based on the parameters of NHR-200II, and RELAP5 code is employed for the simulation of operation processes. A proportional-integral-derivative (PID) control scheme is introduced to maintain the primary loop pressure by adjusting the flow rate of intermediate loop. The PID coefficients are determined and the effect of the control scheme is verified by power adjustment processes. The ability of proposed control scheme to maintain stable operation of NHRs in slight boiling mode is shown.