Impact de quelques techniques de lavage sur la décontamination de tuiles et béton contaminés par du césium et du strontium radioactifs.

C. CAMARASA﷓CLARET, F. PERSIN, J. REAL Radioprotection (2000), 35(1), 45-57

Washing processes impact on the decontamination of tiles and concrete contaminate by radioactive caesium and strontium An accident on a nuclear reactor with a radionuclide deposition on urban surfaces could present a danger of external of irradiation for the populace. In order to evaluate this risk, and taking into account the few available data in the literature, it appeared essential to us to test in the laboratory the efficacy of decontamination techniques on judiciously selected urban surfaces before considering a feasibility study on a large scale. The originality of this work consisted in evaluating by the means of experiments in controlled environment the decontaminating efficiency of a rain event and washings with aggressive solutions on clay tiles and concrete contaminated with strontium and cesium aerosols. The rainwater proved not to be very to be effective in eliminating the radionuclides, the weaker its effect the higher its intensity. A greater efficiency was obtained after 2h30 of washing with the NH4CI (0,1 mol l-1) solution applied directly after the contamination. The residual activity then amounts to 90% on the tiles and 40% on the concrete. The results obtained are average for the concrete but not very satisfactory for the tiles and confirm, under conditions of accidental deposit, the difficulty in moving such a contamination.