Microwave radiation used to immobilise radioactive iodine

Iodine radioisotopes are produced by fission of uranium fuel in a nuclear reactor. Radioactive iodine is of concern because it is highly mobile in the environment and selective uptake by the thyroid gland can pose a significant cancer risk following long-term exposure.

Furthermore, iodine-129, which is a type of radioactive iodine, has an extremely long half life of 15.7m years, so is one of the most significant long-term hazards faced by the population due to its emission during the geological disposal of nuclear waste.

Prof Neil Hyatt, from the university’s Department of Materials Science and Engineering, has now developed a way of locking up iodine radioisotopes in a solid material suitable for ultimate disposal, such as lead iodovanadinite (Pb5(VO4)3I).

To do so, Prof Hyatt and his team created a solid material for immobilisation of iodine with the formula Pb5(VO4)3I, by heating a mixture of lead iodide, lead oxide and vanadium oxide.

Previously, this had only been achieved using high pressure and a sealed container, because iodine is volatilised at high temperature. However, using the knowledge that vanadium is a good absorber of microwaves at 2.45GHz, the team was able to heat the mixture of chemicals in a microwave oven to produce Pb5(VO4)3I in about three minutes.