Modeling the evolution of uranium-233 radioactivity

For the calculation justification and optimization of the fuel cycle on the basis of thermonuclear operating units and nuclear reactors - fuel consumers and as part of the development of the UNK software package, the GAMSOUR software module was developed for calculating the specific and group spectrum of delayed gamma rays in irradiated material and the effective radiation doses of personnel when working with it. The results of verification of the UNK software package for calculating the dose rate of materials containing U-233 with U-232 impurities are presented. The results of the comparison with the dose rate calculations obtained by other programs showed that the differences in the assessment of the dose rate depending on the exposure time of uranium-233 do not exceed several cents over the entire time interval up to 15 years. The results of the research have shown that in order to correctly account for gamma rays sources, it is necessary to take into account the Tl-209 nuclide. The exclusion of this nuclide from the U-233 decay chain leads to a systematic underestimation of the gamma rays source and, consequently, the effective radiation dose depending on the exposure time of U-233. The GAMSOUR software module is implemented as an independent software tool and can be used in software complexes for solving the gamma rays transfer equation.