Crystal binding effect on the effective resonance integral of UO₂ fuel has been evaluated with a simplified phonon frequency distribution. Gaussian frequency distribution having one fitting parameter was adopted. With this distribution the line shape of the resonance cross section was expressed by a superposition of the ψ-functions, which lead to a rather simple calculation of the resonance integral. The calculated results on UO₂ crystal showed about 1% increase in the effective resonance integral at room temperature. Although this effect decreased at an elevated temperature, it conversely makes 5 to 10% decrease in Doppler coefficient com-pared with the free gas treatment.

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The resonance activation integral of ⁵⁵Mn was measured relatively to that of ¹⁹⁷Au by absolute counting on ⁵⁶Mn and ¹⁹⁸Au: ⁵⁶Mn was measured with a Ge(Li) counter whose detecting efficiency for γ-rays had been previously determined by a set of IAEA calibrated γ-sources, while ¹⁹⁸Au was measured with a 4πβ-γ coincidence counter. The neutron spectrum was deter-mined by P1 calculation and was verified by time-of-fiight method.
The ratio I_l/υ/I_res was obtained experimentallymaking use of boron filters of three different thicknesses.
The results were I_total=14.1±0.6 barn and I_l/υ/I_res=0.57±0.06,
for a cutoff energy of 0.63 eV.

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Some fundamental properties of chromatographic alumina, used for the preparation of radio-isotope generators and for the separation of fission products, were examined in connection with pretreatment procedures prescribed for the alumina to improve its properties in respect of alumina dissolution by certain eluants, its adsorption capacity for certain ions, and the effects of differences in the mode of storage.
The commercially available brand of chromatographic alumina used in this work showed an increase in its adsorption capacity and a decrease in alumina dissolution, when it was ignited for 10 hr at 400C and treated thereafter with boiling dilute hydrochloric acid. When treated by the above procedure, the properties of the alumina in respect of dissolution and adsorption capacity were found to be unaffected by extended periods of storage under conditions correspond-ing to normal operation.
The pretreated alumina was made into column form. The dissolution of alumina with vari-ous kinds of eluants and the adsorption capacity for chloride, sulfate, fluoride, tellurite, tellu-rate, and molybdate ions were examined. The dissolution of alumina differed according to eluant, the sequence from larger to smaller dissolution being sodium hydroxide, hydrochloric acid, nitric acid, ammonium hydroxide and sodium chloride. It was also observed that the adsorption capacity and the elution conditions for tellurium and molybdenum were greatly affected by the pH of the solution and their valency.

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For design calculations to determine the local power distribution in a fuel assembly of a power reactor, the neutron flux is usually assumed to be symmetrical at the outer boundary of the assembly. In actuality, experimental data on power distributions are obtained in a finite system where this symmetry does not apply, so that the calculated values cannot be directly compared with observed data. In a zero power critical experiment in particular, the measure-ment must be performed in a fairly small core assembly so economize the amount of fuel materials to be used for simulation. This introduces the necessity of special considerations in the comparison between design and observed data.
The authors propose a method incorporating direct corrections to the experimentally deter-mined power distributions based on the geometrical buckling of the system. In this method the experimental power P₀(r) is divided by the neutron flux Q(r) which is determined in the critical state with geometrical buckling in a bare (one neutron energy group) reactor, neglect-ing the reflector region of the experimental system. A sample application of the method to an actual light water lattice has confirmed the validity of the method.

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