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is involved. It is hoped that the hydrogen-uranium mixing can be controlled by proper selection of initial velocity profiles and upstream geometry.

        Studies related to the plasma reactor concept can be divided into three areas. These are nuclear reactor physics, radiant energy transfer, and turbulent plasma flow. A very comprehensive summary of NASA/Lewis supported research in these areas has recently been published by Ragsdale and Rom (17). The past studies have generally approached the three problem areas by treating each area separately, without including the coupling mechanisms by which nuclear, plasma and radiation effects are related physically. The present study will consider only the coaxial flow system, which appears to be the simplest concept. This system presents a sufficient number of problems, without considering the added complexities of vortex flow or magnetic containment. The purpose of the present study is to identify specific problems in the above three areas, develop methods for relating these problems, and analyze them in a consistent manner. The high temperature uranium is properly treated as a plasma rather than an ordinary gas, and the effects of the plasma characteristics on nuclear criticality are determined. The effects of fuel and coolant inhomogeneities on radiant energy transfer are included. Temperature distributions