The hydrogen isotope radiolytic yields, G(H2), G(HD) and G(D2) were determined in H2O/D2O mixtures under chemical conditions close to a LOCA in a PHWR like Atucha I Nuclear Station, that is 2·10–3 MH3BO3 and p(H+D)=8.5±0.2. The total hydrogen radiolytic yield G(H2+HD+D2) as a function of the deuterium atom fraction goes through a flat maximum at about 0.58. This result in dicates that the 4% flammability limit for hydrogen in the reactor's containment with be reached sooner than what is expected assuming a linear combination of pure H2 and D2 radiolytic yields. Hydrogen radiolytic production in 10–3 M KBr in H2O/D2O mixtures gives the same results as in the boric solutions suggesting a bimolecular B(OH)
+OH reaction. Identical isotope concentration factors were calculated for both solutions.
The specific effect due to Gd3+ ion on the radiolysis of aqueous nitrate solutions was determined by measurement of H2, H2O2 and NO
radiolytic yields produced by gamma-irradiation of aerated and deaerated solutions of gadolinium, sodium and calcium nitrates in the concentration range of 10–5 to 0.3M. Important O2 consumption in aerated and O2 evolution in deaerated Gd(NO3)2 solutions was found by radiolysis in comparison with the inert cations nitrates. In the former the Gd3+ ion generates an O2 transporter producing an increase in the H2O2 yield and a decrease in the NO
yield, while in the latter it enhances the H2 and NO
production with respect to the same nitrate concentration of the Na+ solutions.