Neutronics Characteristics Study of Conceptual Space Heat-Pipe-Cooled Fast Reactor Core

Abstract

With the continuous development of space exploration activity, the demand for space energy is increasing. Energy supply has become a very important guarantee for the normal operation of all kinds of space equipment. Therefore, the high-power and long-life space nuclear reactor, which can be operated automatically and not be affected by environment, becomes a very important choice for space energy system. In this paper, a space fast reactor core design scheme based on an integrated structure which combines the nuclear fuel rods and the central cooling heat-pipes was proposed initially. The fuel rod is a regular hexagonal prism, and the evaporator section of the heat-pipe is placed in the central hole of the fuel rod. The control of the reactor depends on six control drums in the side of the reflector. The neutronics characteristics of the reactor core were studied. The reactor core design scheme was calculated and analyzed through the establishment of the core calculation models by means of MCNP. The main dimensions and physical parameters of the reactor core were given, and the critical reactivity, power distribution and burnup of the reactor core were obtained. The fuel filling rate was improved because of the compact layout of the design scheme, which led to a reduction in the critical mass and the core volume of the reactor. At the same time, the use of structural material also decreased. As a result, the total mass of the core reduced. An increasing relative density of heat-pipe arrangement could avoid the problem generated by the failure of single heat-pipe effectively. Consequently, it has high safety and good reliability.