[en] The Szilard-Chalmers effect in solid was investigated. In order to study the initial distribution of ¹²⁸ I O₄ as a function of neutron flux, samples were irradiated utilizing both the manual vertical irradiation channel and the thermal column of the ET-RR-1 Research Reactor in Egypt. The initial retention was reached a maximum of 40% after 120 minutes at 5.5 x 10⁸ ns^-1 cm^-2. The data was analysed using first order reaction. As a result, the activation energy and the vibration constant were found to be E = 0.95 eV and K = 2.82 x 10¹¹ respectively. Kinetics comparison of the deshydration and irradiation reactions for this solid shows disorder in the crystallographic form. Such disorder may be the result of deshydration or irradiation reaction, where the loss of water molecule will lead to formation of vacancies which, in turn, are responsible for the distribution process. (author). 17 refs., 3 figs