Assessment of the radiation chemistry of water and aqueous solutions at elevated temperatures

Recently obtained experimental data which are relevant to the chemistry of water-cooled reactors are summarised and assessed. Several reports on the yields of some of the primary radiolytic products from water are broadly in agreement that the pattern of water radiolysis does not change very markedly between room temperature and ca. 250 deg. C. The yields of radicals (eaq-, H, OH) increase smoothly by ca. 0.2% per deg. C in neutral solution, and by ca. 0.1% per deg. C in 0.4 mol dm-3 H2SO4. The pK's of OH and HO2 show temperature dependences typical of weak acids. It is concluded that yields and pK's can be extrapolated to reactor temperatures with some confidence. Kinetic measurements reveal that some important reactions which are diffusion controlled at ambient temperature become activation controlled at elevated temperatures. (author). 21 refs, 3 figs, 2 tabs