The radiolytic oxidation of methane in commercial advanced gas cooled reactors

Measurements of the rate of CH4 destruction in Hinkley Point 'B' AGR at different coolant compositions have indicated a higher CO concentration dependence than would have been expected from calculations based on previously used empirical expressions. The present results suggest much higher methane destruction rates at low CO concentrations. This has important implications on the sizing of the coolant control plant for future CAGRs and further tests may therefore be required to confirm the observed trend. If the comparatively simple expression for the CH4 destruction rate as a function of coolant composition derived in this paper is confirmed, it should be possible to derive reasonable values for full power CH4 destruction rates from measured data at lower powers, by a nuclear flux correction alone. (author)