As part of a validation study of burnup calculations of BWR cores, lattice physics analyses were performed on the measured burnups and the isotopic inventories of U, Pu, and Nd isotopes of eight samples taken from 9Â9-9 BWR fuel assemblies of three and five cycles of irradiations. Burnup calculations in assembly geometry were carried out with a neutronics code system, SRAC, and a Monte Carlo burnup calculation method, MVP-BURN, based on a nuclear data library, JENDL-3.3. The measured burnups were determined based on the Nd-148 method, where the fission yield of 148 Nd, energy release per fission, and correction factors for neutron captures by 147 Nd and 148 Nd were analytically obtained by averaging with burnups. The C/Es of the sample burnups are 0.96 to 1.07 for both analysis methods. By modifying the power histories to adjust the calculated burnups to the measurements of the samples, burnup calculations were performed again and the isotope inventories were compared with the measurements. The C/Es of the inventories are 1.00 to 1.09 for 235 U, 0.91 to 1.04 for 239 Pu, 0.96 to 1.07 for 240 Pu, and 0.90 to 1.02 for 241 Pu for the six samples excluding those of a corner fuel rod.

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The Na‐P1‐type zeolite having a high cation‐exchange capacity (CEC) was obtained using the waste coal fly ash from thermal power stations and a 2M NaOH solution at 100°C. The Na‐P1‐type zeolite was formed with the reaction time of 6 h at 100°C, and its CEC value increased with an increase in the reaction time. The addition of a suitable amount of NaAlO2 to the fly ash was also effective for improving the CEC value. A new composite material consisting of the Na‐P1‐type zeolite and magnetite was synthesized from the fly ash and iron chlorides because the magnetic collection was possible using this composite material after radioactive Cs+ ion adsorption. The existence of nanosized magnetites in the polycrystalline zeolite (several micrometers) was confirmed by TEM observations. The CEC and magnetic property of these composite materials were characterized.