The oxidation state of fission fragment iodine in potassium chloride

Iodine isotopes in fission fragments formed by recoil from a film of uranium oxide into solid potassium chloride during reactor irradiation, have been shown to exchange with both oxidised iodate and reduced iodide carriers. On annealing after the irradiation the oxidised form of the fission fragment decreases initially, and then increases relative to the reduced form depending on the temperature of the annealing. The effect is interpreted quantitatively as a reaction with electron donors, such as chloride ion defect centres formed in the lattice, which also undergo a simultaneous annealing process to form electron acceptors, such as chlorine. Estimates are made of the activation energies involved. (author)