The behavior of radiation-produced gas atoms in Al-Li alloys was observed by means of ³H autoradiography. The technique is extremely useful for studying the behavior of gas atoms in specimens containing ³H in concentrations of the order of 10^-5 in atom fraction. Cold-worked microstructures of the specimen are also revealed in the autoradiographs. However, the effect of β-phase on the behavior cannot be observed by autoradiography.
Precipitation of the gas atoms could not be discerned within the grain in specimens irradiated in JRR-2 at ambient-water temperature.. Upon heating to 200°C, ³H was seen to precipitate along the dislocation within the grain and denuded zones free of the precipitate appeared along the grain boundaries. The amount of ³H remaining in the specimen decreases with rising heating temperature. In the case when the concentration of radiation-produced gas atoms contained is the order of 10^-5 in atom fraction, gas bubbles are observed in autoradiographs of specimens heated at a temperature as high as 500°C. On the other hand, bubbles are hardly observed in specimens heated at the same temperature when gas atoms are contained in concentrations of the order of 10^-4. Cold-working after irradiation accelerates the migration of gas atoms and the growth of gas bubbles.

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Measurements have been carried out on the electrical resistivity ρ (4°∼1, 100°K) and absolute Seebeck coefficient (77°∼800°K) of uranium carbonitride UC_1-xN_x (0_??_x_??_1), which has a NaCl structure. The electrical resistivity of various compositions from UN to UC_0.4N_0.6 exhibit changes, near the Néel temperature, in the slope of the lines relating the resistivity to temperature. From the resistivity-temperature relation, the temperature derivative dρ/dT has been determined in particular detail in the vicinity of the critical region, and the Néel temperature has been derived therefrom, for compositions from UN to UC_0.4N_0.6. A qualitative band picture is proposed based on the results of the composition-dependence of the temperature derivative of the Seebeck coefficient dS/dT. The composition-dependence of the electrical resistivity of UC_1-xN_x is discussed with reference to the density of state obtained from specific heat measurements reported in literature. The resistivity of the spin disorder term ρ_m∞ for compositions from UN to UC_0.4N_0.6 change apparently in the relation ρ_m∞_??_x5, and this is discussed in reference to the RKKY theory.

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Direct preparation of Na₂³⁵SO₄ from neutron irradiated KCl has been studied. Irradiated KCl was dissolved in water and passed through a H⁺-form cation exchanger column to remove K⁺ions. The effluent, after the addition of Na₂SO₄ carrier, was neutralized with NaOH. From this solution was separated solid Na₂³⁵SO₄ by the addition of ethanol, leaving NaCl in the solution.
Certain factors such as ethanol concentration and pH of the system, from which labeled sulfate was precipitated, as well as the amount of carrier, were found to affect greatly the recovery of the labeled sulfate. Conditions that bring about sufficiently high recovery were determined, and an effective means was established to prevent contamination with ³²P, a by-product formed by neutron irradiation of Cl.
Similar procedures have been examined to prepare labeled potassium sulfate.

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The slowing down equation for an infinite homogeneous monoatomic medium is solved exactly. The solution is obtained in analytical form. The calculated collision density is compared with the one obtained by Teichmann and Stefanovi'c respectively. For the special case of hydrogen, the present solution reduces to Bethe's solution.

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The carbothermic reduction in vacuum of thorium oxide with graphite has been studied with the aid of a high temperature thermobalance at temperatures range of 1, 300°∼1, 900°C. The effects of differences in the reaction temperature, molecular ratio of the reactants, and in the state of the reactants such as differences between loose powder mixture and pelleted form were examined. The reaction rate obeyed the diffusion-controlled kinetic equation, and an activation energy of 75±4 kcal/mole was obtained as a mean value of all the different cases covered, Some X-ray analyses of the product were carried out, which revealed a final product of ThC phase alone resulting from the C/ThO₂ mole ratio of 3, while with ratio of 4 the product contained a mixture of ThC and ThC₂. The reaction mechanism is also discussed briefly.

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A simple analyses is presented concerning the total response observed in neutron wave experiments under conditions outside the asymptotic mode region in finite polycrystalline media.
A discontinuity of the pseudo-fundamental eigenvalue due to sub-Bragg neutrons and the disappearance of the cold-neutron dominated discrete eigenvalue are indicated in the low-frequency region in finite polycrystalline media under ordinary experimental conditions. The analytically continued dispersion relation cannot explain the space- (or time-) dependent and system dimension-dependent experimental results in the pseudo-fundamental mode region. Here, the total solution including such contaminating components as the sub-Bragg neutron continuum or the spatial higher mode is obtained in an integral making use of suitable models and simple approximations.
The portion having the largest excitation amplitude in the solution is analyzed by a "saddle-point method" appled to the integral, and a simple relation for the effective relaxation coefficient observed in the experiment is derived. Numerical calculations give satisfactory agreement with experimental results in graphite, and the experimental conditions desirable for the exact observation of the pseudo-fundamental eigenvalue are discussed as well as practical results obtained for graphite.

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The conditions under which curium can be separated from irradiated ²⁴¹Am target were elucidated. The isolation process consists of three steps: In the first step, Am(III) is oxidized to pentavalent state in a dilute nitric acid solution, and then plutonium and curium are extracted from the irradiated target by solvent extraction with HDEHP. Curium in the organic phase is back-extracted with 1N nitric acid, and thereafter plutonium with a reducing solution containing ferrous sulfamate. The curium is finally purified by cation exchange, using α-hydroxy isobutyrate as the eluting solution. About 0.4μg of ²⁴²Cm and 4×10^-3μg of ²⁴³Cm were found in the curium fraction, which had been separated from 1mg of irradiated ²⁴¹Am sample.

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