Shielding design and heat transfer analysis of the transportation container of a hot batch in the Mo production facility.

In molybdenum-99 (Mo) production facilities via the fission method, appropriate transportation containers must be used to transfer irradiated targets from the irradiation facility to the processing facility, following the requirements for transferring radioactive materials. In the Mo production industrial plan of Iran, the transportation container must be capable of carrying a holster containing nine irradiated low-enriched uranium targets, known as a hot batch. In this article, the proper shielding of two-layer containers based on the gamma spectrum emitted from the radioisotope inventory of a local hot batch, including fission products, activation products, and other radioisotopes produced from their decay chains, was investigated by using Monte Carlo code MCNP6. The simulation results indicated that a two-part container including a moving part of depleted uranium with a thickness of 7 cm and a fixed part of lead with a thickness of 7.2 cm could be an appropriate choice for the local hot batch transport. Also, heat transfer analysis using ANSYS software showed that transporting the hot batch immersed in water inside the container improved thermal distribution.