This paper deals with the lift of the electron temperature in the electromagnetic field. In view of the small ionization degree in the working gas of MHD power generation, the collision of charged particles with each other is assumed to be negligible. Under this assumption the differential equations to determine the collective behavior of electrons in the electromagnetic field were derived from the Boltzmann equation, and have served to yield some theoretical information on the lift of electron temperature.
The electron temperature reaches a new steady value in about 10/μsec after the application of an electromagnetic field, and the temperature increase is proportional to the reduced mass of main and seed gas particles if the seeding rate is properly chosen to obtain maximum electrical conductivity of the working gas. Furthermore, the electron temperature increase is of the order of 100°C in typical MHD power generators operated on He +Cs gas. This means that the ionization degree of the seed material, and consequently, the electrical conductivity, are expected to increase by about 30% compared with those corresponding to the gas temperature, when considering practical ranges of operating

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In connection with a program to study the behavior of punctured fuel elements for the Tokai Atomic Power Reactor, the diffusion coefficient of fission gas in uranium oxide powder formed by CO₂ oxidation of U was determined by post-irradiation experiment, in which the fractional release of fission gas during isothermal heating of the powder was measured. The U was oxidized at 600 ?? and 700 ??, and in both cases the O/U ratio of the oxides, measured gravimetrically, was 2.0. The diffussion coefficients in the oxide powder formed by oxidation at 600 ?? were found to be 1.4× 10^-20, 1.3×10^-19, 1.1×10^-18 and 1.0×10^-17cm²sec^-1, respectively at 450 ??, 550 ??, 650 ?? and 750 ??, and in the oxide powder formed at 700 ??, 7.4×10^-19 and 3.6×10^-16cm²sec^-1 at 600 ?? and 700 ??, respectively. Activation energies calculated for the two oxide powders were comparatively low.

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A higher order effect was found in the transfer function measurements on the Argonaut Reactor at the Argonne National Laboratory. The gain and phase were altered when the direction of rotation of the pile oscillator was reversed. This effect can be explained by considering higher spatial modes and the dipole characteristics of the oscillator. The dipole represents the finite dimensions of the pile oscillator, which is a corrective term when the monopole effect is dominant.

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The fluorination of U₃O₈ powder by BrF₃ vapor was attempted. The reaction proceeded even at 67°C and under 10 mmHg BrF₃ partial pressure, producing UF₆. The reaction rate increases with temperature up to about 220°C, and its activation energy is 0.9kcal/mol. The reaction rate, however, decreases at temperatures slightly above 220°C and rises again after passing through a minimum at 225°C-230°C.

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An approximate calculation method for unscattered flux from spherical and cylindrical sources with a slab shield is presented. The method is based on modifying the source geometry to a form convenient for calculation: The sphere is approximated by a conical fragment of spherical shell, and the cylinder by a columnar fragment of cylindrical shell. The procedure for manual calculation is relatively simple, and the difference between results of appoximate and exact calculations is less than +5% for large sources (μs, R0>4), and±15% for small sources (μsR0=0.25). Graphs of the functions for approximate calculation are presented. The method has several advantages over Rockwell's method.

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