Multiplication characteristics of a gas-cooled ADS with fast-thermal coupling configuration

The design of the subcritical core is based on the scheme of high temperature gas-cooled reactor, and to improve the ability of transmutation, the subcritical core is divided into two regions, which form up the fast-thermal coupling configuration. The parameters of fuel arrangement, position of target, height of active core, and height of top/bottom reflector are optimized to achieve the good physical and thermal performance. In the process of optimization, the influences of these parameters on the characteristics of the core are investigated through numerical experiments simulated by the MCNP6 code. The results indicate that the Keff and the Ks may differ considerably for the gas-cooled ADS with fast-thermal coupling configuration. Moreover, we find that even with the same Keff, the Ks of the subcritical core is different for similar schemes.