AbstractThe kinetics of the radiation-induced reactions of carbon monoxide with either an equimolar mixture of deuterium and tritium or pure tritium was investigated at several total pressures and within a range of concentrations that simulate those expected in the fuel cycle of a fusion machine, i.e. 1–6% CO in DT or T2 containing 0–8% He. The reaction rate was found to be directly proportional to the initial tritium concentration in the gas mixture. From the initial rate of CO pressure decrease, an average CO consumption yield per ion pair of 1.6±0.8 was calculated from a total of 24 experiments. At a constant composition of CO, DT and He, the rate of CO consumption decreased strongly with decreasing total pressure. The main gaseous products found were per-tritiated methane, per-tritiated higher hydrocarbons, and carbon dioxide. Water and possibly formaldehyde were identified as minor products. Heated palladium/silver from permeators such as used in fusion machine fuel clean-up considerably enhance the radiation-induced reaction rate between tritium and carbon monoxide.