The new conversion refining process using high molecular weight alkylamines was developed in order to obtain directly highly purified UF₄ or UO₃ from ore leaching solution without the precipitation process of yellow cake. Suitable conditions for each of the extraction, conversion and stripping process were described, and also the flow diagram of this new refining process was shown.

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Spatial dependence of thermal neutron spectra in spherical core-reflector D₂O-system was studied by using ¹⁷⁶Lu, Mn and Dy. The sub-cadmium activation ratios of non-1/υ to 1/υ detectors were analysed instead of thermal activation ratios. A remarkable spatial change of thermal neutron spectrum was observed in a small core system.
The good agreement was found between the experiment and the proposed theory with a effective mass, 5.0 amu, of D₂O molecule.
The infinite medium spectra also were calculated with the monoatomic gas model of effective mass, 3.6 amu and were compared with experiments. In this case also, the good agreement was obtained between the experimental valves and the theoretical ones estimated from infinite medium spectra.
The slightly heavy effective mass obtained from analysis of the spatial distribution is discussed.

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A new swellingless and large particle exchanger was prepared by calcination of bentonite which belongs to a representative of montmorillonite group, and its adsorbability for strontium ion has been examined.
The calcination is not affective to the exchange capacity up to 500°C, however, it decreases with the rise of calcination temperature above 500°C. The rate of the decrease in its capacity was maximum in the exchanger treated with sodium hydroxide. There was not found a simple relation between the concentration of acid and the rise of the capacity, on the other hand, there is a semi-logarithmic relation between the concentration of sodium hydroxide and the capacity. Only Na-form exchanger except Natural- and H-form can be used in column for the removal of strontium, because both latter have very low capacity for it.
It is concluded that Natural-form bentonite had selectivity for cesium ion as the result of very low capacity for strontium comparing with cesium.
However, montmorillonite is possible to have a high capacity for strontium corresponding to cesium in the treatment with sodium hydroxide.

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The breakthrough experiments of U(IV) and U(VI) have been done through an anion exchange resin column of 100 cm height and 1.2 cm diameter with 8_N-hydrochloric acid.
Uranous ions gave better separation factor (0.9993) than uranyl ions (1.0000) just as in the case of cation exchange resin reported in the previous paper. The mixed solutions of uranous and uranyl ions gave much favorite separation factors (0.99920.9986), which can be explained by effective contribution of the isotope effect of electron-exchange reaction.
²³⁵U(VI)+²³⁸U(IV)_??_²³⁸U(VI)+²³⁵U(IV)
The whole experimental results agreed with the theoretical values derived from the following fundamental equation by assuming ke=1.002.
ln S₂₃₈²³⁵(U)=ln S₂+ln{1+S₁keS₂^-1-1/1+ρ}+ln{1+(ke_-1-1)/1+ρ}
where S₁ is the separation factor with the system containing only uranous ions, S₂ is for uranyl; ρ and ρ are the ratios of uranyl ions to uranous ions in the solution and in the exchanger resin, respectively.

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The investigation of the mechanism of skin contamination was carried out by a living rabbit skin in the same manner as that of pig skin^†. The rabbit skin was contaminated with carrier free ⁹⁰Sr-⁹⁰Y or ³²P. Consequently, the adhered contamination of epidermis (abbr.; the adhered contamination) or the permeated contamination of dermal (abbr.; the permeated contamination) was obtained in the like result as that of pig skin. In regard to ⁹⁰Sr-⁹⁰Y and ³²P, the adhered contamination increased steeply within 30 min after contamination and then it increased gradually with an increase of contaminating time. Result obtained also showed that according to pH, ⁹⁰Sr-⁹⁰Y indicated the large difference but ³²P almost all did not indicate such difference in the adhered contamination. On the other hand, the definite permeated contamination was obtained at the long time contamination without the case of acidic ³²P, although there was no regularity in the tendency to the permeated contamination. Particularly, ⁹⁰Y contributed considerably to the adhered contamination and the permeated contamination, if the contaminating solution of ⁹⁰Sr-⁹⁰Y is alkaline. Furthermore, the result obtained recommends an early decontamination-within 30 min after contamination-is of great advantage to a decontamination of human skin.

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Recent progress of radiation chemistry on polymers in Japan has been reviewed from 39 papers which were presented in 5th Conference of Radioisotopes 1963 Tokyo.

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