CHAPTER IV

        PRESSURE-TEMPERATURE ANALYSIS OF URANIUM PLASMA FUEL REGION


Introduction

        In order for the uranium fuel region to function efficiently as a source of energy in the plasma core reactor, the uranium should exist at temperatures in the 50,0000K to 100,0001K range. Under these conditions, heat transfer is accomplished primarily by radiation. At these temperatures, the uranium fuel is highly ionized and must therefore be treated as a plasma rather than an ordinary gas. Since uranium becomes appreciably ionized at temperatures above a few thousand degrees Kelvin, the plasma effects are important at all temperatures of practical interest. In performing a nuclear analysis or radiative heat transfer analysis of an externally moderated high temperature reactor, these plasma effects must be considered. In order to account for these effects, it is necessary to determine the composition of the uranium plasma fuel region as a function of plasma temperature and pressure. Basic Equations for Arbitrary Temperatures

        An uranium plasma in local thermodynamic equilibrium is characterized by the following set of equilibrium ionization and recombination reactions. The uranium atom and


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