serves as a heat source through liberation of radiant energy from fissioning uranium nuclei. The radiant heat transfer from the uranium plasma to the hydrogen coolant plasma is accomplished by seeding the coolant with a material which is sufficiently opaque to reduce the coolant-wall interface temperature below the melting point of graphite. The radial mixing of flowing uranium and hydrogen is simulated by use of analytic expressions. Numerical techniques are developed for the engineering analysis of the principle characteristics of the fissioning plasma reactor, under conditions of local thermodynamic equilibrium.

        The reference model study leads to several basic requirements which must be satisfied in order to develop an operable fissioning plasma reactor. The nuclear analysis of such problems as critical mass, reactivity balance, and kinetic behavior must treat both the fuel and coolant as plasma regions rather than ordinary gases. In order to sustain a critical uranium mass at the desired high temperatures, pressures as high as 1000 atmospheres will be required. In order to heat the relatively transparent hydrogen coolant and also to prevent melting of the graphite containment, the coolant will have to be seeded. Additional theoretical and experimental studies of plasma instabilities associated with the coaxial flow of uranium and hydrogen are needed to analyze such problems as system


xii