A Preliminary Core Design of the Space Nuclear Reactor

Los Alamos national laboratory(LANL) is the first developer to use uranium in space reactors instead of plutonium which used for the first time by NASA. In this paper, we proposed a new concept of the space reactor based on the thorium fuel with helium gas cooling. Some design parameters are proposed including neutron distribution and spectrum by using MCNP6.1 code system. In Addition, a depletion analysis is carried out to estimate the life cycle of the suggested space reactor. Neutron distribution of the space reactor is shown in the three different energy ranges such as thermal, epithermal and fast energies as shown in Fig. 3. It shows that the spectrum is dominated in the fast energy region. Fig. 4 depicts the neutron spectrum, which shows the typical fast spectrum. The depletion calculation of the space reactor is performed by using the BURN card, which is combined with CINDER depletion module. It is estimated that about 5 years cycle is possible with this design as shown in Fig. 5. And it is expected to increase upto 30 years by changing the composition of U-233 contents and core configuration.