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Conference Article: Evaluation of a decontamination model

Rippin, D.W.T. (Eidgenoessische Technische Hochschule, Zurich (Switzerland)); Hanulik, J.; Schenker, E.; Ulrich, G. (Swiss Federal Institute of Technology, Wuerenlingen)

Abstract

In the scale-up of a laboratory decontamination process difficulties arise due to the limited understanding of the mechanisms controlling the process. This paper contains some initial proposals which may contribute to the quantitative understanding of the chemical and physical factors which influence decontamination operations. The basic concept of decontamination by wet chemical treatment is that the activity near the surface boundary is removed as the surface itself is dissolved away by the decontaminating fluid. Earlier work has demonstrated that the extent of penetration of active material into the contaminated surface can be either predicted or measured. Thus, the depth to which the surface layer should be removed to achieve the desired level of decontamination can be determined. Understanding of the decontamination process will allow the determination of the most appropriate conditions for the controlled removal of the surface layer to the required depth at any scale of operation. If a mathematical model of the process can be developed which describes with acceptable accuracy the behaviour of the process as a function of the design and operating conditions, such a model will be of considerable assistance in the interpretation of labortory data and the subsequent problems of scale-up, design and operation.

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key words: chemical reactions; decontamination; depth; diffusion; mathematical models; surface contamination; cleaning; contamination

Reference:: Specialists meeting on coolant chemistry, plate-out and decontamination in gas-cooled reactors Juelich, Federal Republic of Germany 2-4 December 1980; International Atomic Energy Agency, Vienna (Austria); IWGGCR--2, pp:107-113