Research on Physical Properties of Long Life Core Using Thorium-Uranium Fuel

The neutronics characteristics of the square assembly that employs the homogenous thorium-uranium fuel have been analyzed and evaluated, and the numerical results show that the infinite multiplication factor of fuel assembly decreases more slowly with the increasing burnup. In other words, better reactivity performance could be provided, from the neutronics point of view, this is very good for the increasing of the reactivity control ability. On the basis of these above, the conceptual design of the long-life core using thorium-uranium fuel has been developed. The obtained physical design parameters show that its lifetime can reach up to 1000 equivalent full power days, the utilization ratio of ²³⁵U is 51.3%. The physical properties analyses presented that it is a very effective method to achieve the long-life core loading schemes for the use of thorium-uranium fuel in compact pressurized water reactors.