In-core fuel management strategy for the basket-fuel-assembly molten salt reactor

Molten salt reactor,with good economics and inherent reliability,is one of the six types of Generation Ⅳ candidate reactors.The Basket-Fuel-Assembly Molten Salt Reactor (BFAMSR) is a new concept design based on fuel assemblies composed of fuel pebbles made of TRISO-coated particles.Four refueling patterns,similar to the fuel management strategy for water reactors,are designed and analyzed for BFAMSR in terms of economy and security.The MCNPX is employed to calculate the parameters,such as the total duration time,cycle length,discharge burnup,total discharge quantity of 235U,total discharge quantity of 239pu,neutron flux distribution and power distribution.The in-out loading pattern has the highest burnup and duration time,the worst neutron flux and power distribution and the lowest neutron leakage.The out-in pattern possesses the most uniform neutron flux distribution,the lowest burnup and total duration time,and the highest neutron leakage.The out-in partition alternate pattern has slightly higher burnup,longer total duration time and smaller neutron leakage than that of the out-in loading pattern at the cost of sacrificing some neutron flux distribution and power distribution.However,its alternative distribution of fuel elements cut down the refueling time.The low-leakage pattern is the second highest in burnup,and total duration time,and its neutron flux and power distributions are the second most uniform.