Diffusion in an arc plasma across a magnetic field is investigated. The geometry is similar to that reported in ORNL-1890 but with the addition of magnetic mirrors on the ends of the arc chamber. It is shown that mirrors do not eliminate the "short circuit" effect. Comparison of the e-folding length, rₒ, of the radial ion density with and without mirrors, affords a direct measurement of ℓ/λ where ℓ is the arc length and λ the mean-free-path. In addition rₒ is independent of gas pressure with mirrors and varies as √p without mirrors. The condition for the elimination of the "short circuit" effect is discussed, as well as the case in which the "short circuit" is still present but the ions diffuse (rather than stream) to the end walls. In this case rₒ is directly proportional to the gas pressure. These effects are compared to some experimental results of Neidigh

This quarterly progress report discusses ongoing work at the Metallurgy Division at the Oak Ridge National Laboratory. Topics discussed include thorium research, the preferred orientation of uranium, studies in the ceramics laboratory, the homogenous reactor program, studies in the x-ray laboratory, studies in the metallographic laboratory, the experimental plate-cladding program, and fuel and control element fabrication.