Radiolysis of methyl iodide in aerated borate spray solution

The radiolytic decomposition of methyl iodide in aerated borate spray solution by γ-rays at room temperature results in the formation of I-, CH3OOH and CH4. The initial yields of I- and CH300H increase with the increasing CH3I concentration. The concentrations of all products of CH3I radiolysis decrease with increasing absorbed dose. The potential influence of CH3I on the radiolytic products from water, G(H2O2) and G(H2), was also investigated. The values of G(H2O2) diminish both with increasing concentration of CH3I and the absorbed dose. No CH3I was found in the solutions irradiated with doses of the order of 105 to 106 Gy corresponding to those expected after a loss-of-coolant accident. The agreement between the decomposition of CH3I and formation of I-observed at all doses and all CH3I concentrations suggests that I- is the only iodine-containing radiolytic product. (author)