Dose rate estimation of gamma-rays emitted from a LEU miniature plate

The LEU miniature plate irradiated in the Tehran Research Reactor, which produces the radioisotope molybdenum-99, is a radioactive source consisting of various radioisotopes. Before any practical application, it is necessary that the dose rate of gamma rays emitted from this source be calculated. This was done for comparison with the recommended dose rates for radioactive materials transport and radiation protection of employees during hot tests. In this paper, the validity of a proposed method for calculating the dose rate of gamma rays emitted from hot targets was investigated, experimentally. The Monte Carlo code MCNPX and multi-step algorithm written in MATLAB were used in the proposed method. The results showed that the calculated dose rate was always lower than the measured dose rate. Therefore, based on a conservative view, it is better to multiply the calculated dose rate values by 2 and then compare them with the allowable limits. This will enable you to determine the appropriate shield thickness.