Gaseous Fission Reactor - Theory of Operation

Theory of Operation

The vapor core reactor (VCR), also called a gas core reactor (GCR), has been studied for some time. It would have a gas or vapor core composed of UF₄ with some 4He and/or 3He added to increase the electrical conductivity, the vapor core may also have tiny UF₄ droplets in it. It has both terrestrial and space based applications. Since the space concept doesn’t necessarily have to be economical in the traditional sense, it allows the enrichment to exceed that which would be acceptable for a terrestrial system. It also allows for a higher ratio of UF₄ to helium, which in the terrestrial version would be kept just high enough to ensure criticality in order to increase the efficiency of direct conversion. The terrestrial version is designed for a vapor core inlet temperature of about 1500 K and exit temperature of 2500 K and a UF₄ to helium ratio of around 20% to 60%. It is thought that the outlet temperature could be raised to that of the 8000 K to 15000 K range where the exhaust would be a fission-generated non-equilibrium electron gas, which would be of much more importance for a rocket design. A terrestrial version of the VCR’s flow schematic can be found in reference 2 and in the summary of non-classical nuclear systems in the second external link. The space based concept would be cut off at the end of the MHD channel.