Shielding Designs for Radioactive Material Transportation Canister

Abstract

Gamma-ray shielding is important for the container of radioactive material emitting photons. This study aimed to propose new canister shielding designs for radioactive materials transportation by using well-known materials in terms of shielding performances, costs, and total weights. The calculations were carried out using MCNP 6.2 software. 5.26 x 107 Bq, 0.6617 MeV energy Cs-137 was used as a radiation source in all simulations, and dose results were gathered from a point at the outer surface and one meter away from the canister surface. The dose equivalent is used to convert the photon energy to dose rate (mSv per hour). The geometry used in the simulation is a standard cylindrical 200L drum geometry (canister). There are restrictions for transportation canisters; the proposed designs should have high shielding capacity while lower total weights and lower costs are desired. As a result, the designs focused on in this study could potentially be a new radioactive waste shielding material compared to others. Many transport casks are made of 2 ~ 3 cm thick steel, so calculations were made on the total thickness of 1, 3, and 5 cm for all materials. The study did not consider concrete because it always requires thick use for shielding, and lead, steel, and copper have different pros and cons. Tungsten is heavy and expensive, but combining lead glass at the right thickness yields good results. Still, the steel-lead glass combination in a sandwich form gave excellent results. In other words, instead of making canisters from single materials such as steel or lead, using glass sandwiched between the plates gives much better results.