Neutronic Analysis of the Uranium Tetra-Fluoride, Ultrahigh Temperature Vapor Core Reactor System

摘要

Static and dynamic neutronic analyses, are being performed, as part of an integrated series of studies, on an innovative uranium tetra-fluoride (UF/sub 4/) Ultrahigh Temperature Vapor Core Reactor (UTVR)/Disk Magnetohydrodynamic (MHD) generator for space nuclear power applications. This novel reactor concept operates on a direct, closed Rankine cycle in the burst power mode (hundreds of MW/sub e/, for thousands of seconds). The fuel/working fluid is a mixture of UF/sub 4/ and metal fluoride. Preliminary calculations indicate high overall system efficiencies (x2O%), small radiator size (x5 m/sup 2//MW/sub e/), and high specific power (x5 kW/sub e/kg). Neutronic analysis has revealed a number of attractive features of this novel reactor concept. These include some unique and very effective inherent negative reactivity control mechanisms such as the vapor-fuel density power coefficient of reactivity, the direct neutronic coupling among the multiple fissioning core regions (i.e., the central vapor core and the surrounding boiler columns), and the mass flow coupling feedback between the fissioning cores.