Effects of ionizing radiation on iodine chemistry in the containment

Effects of ionizing radiation on iodine chemistry in the containment 

Time (hours) P dose rate (Gy/h) y dose rate (Gy/h) 

The radiolysis of water leads to the appearance of a large number of oxidizing and reducing radical and molecular primary products in pure water, absorption of 100 eV y radiation results in the decomposition of water according to the generally accepted equation 

In non-aerated solutions water radiolysis does not change the pH of the solution, while in aerated solutions it lowers the pH. The most important radiolysis products with respect to iodine chemistry are the radicals OH-, eaq , H- and the molecules H2O2 and H2. Some of these primary products are highly reactive, leading to secondary reactions and resulting in a final composition which depends on the radiation dose rate as well as on the nature of the constituents of the solution. As an example, an increase in the radiation dose rate results in an increased formation of H2O2, which in tium may react with Caq to form the OH- radical and the OH ion on the other hand, formation of the oxidizing OH- radical may be suppressed 

In the radiation-induced reactions, the yields of the different iodine species depend on the solution pH. With increasing pH, the radiolytic I2 yield generally decreases, reaching very low values at pH 6 to 7 (see Fig. 7.33., according to Lin, 1980 Weber et al., 1991). In acid solutions, I will be oxidized by radiolytically produced OH- and H- radicals, as well as by H2O2, to form I2 according to the sununary reactions 

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