The study of molten-salt target/blanket systems with one-directional coupling

Some sub-critical molten-salt target/blanket systems with an expected one-directional coupling of neutrons were numerically studied. The analysis has shown that there exists an essential back coupling in the system with U235-U238 'active' target that may be explained by transport of neutrons of intermediate energies in backward direction while the system with threshold fissioning material Np237 being more decoupled. It has been shown that relative reactivity (and power) response of the system with one-directional coupling and operating at the level of 1% sub-criticality on the change of fuel concentration is the same as for the system without this property operating at the level of sub-criticality 5-10%. This means that 5-10 times lower proton beam current in an one-directionally coupled system provides the same level of safety as in the system without this property. 4 refs., 3 figs., 7 tabs