On the Contamination of Platinum with Fission Products and the Decontamination of Contaminated Platinum with Acids

The contamination of platinum with nuclear fission products and its decontamination has been studied. Platinum plates were contaminated by soaking in a solution of fission products. The contamination increased with increase of the soaking time, and was saturated in about 3 hr. It was confirmed by the methods of autoradiography, electron microscopy and optical microscopy that the contamination was markedly affected by the surface condition of platinum. The results of the experiments of the decontamination are summarized as follows: (1) Decontamination with tap water: A sample soaked in the solution of fission products only for a short time was easy to decontaminate and the amount of the residual contamination reached equilibrium more rapidly than in the long-soaked sample. (2) Decontamination with acids: HCl, HNO3, H2SO4, H3PO4 and HF were tried. The effect of temperature on the decontamination was very significant. The decontamination with HCl of high temperature was more effective than with the other acids. (3) Decontamination with fused salts: The decontamination with fused KHSO4 was more effective than with the acids and other fused salts. Only one immersion of the contaminated platinum plate into fused KHSO4 could remove 99.4% of the contamination. Finally, it may be confirmed that the degree of the contamination of platinum with fission products is very low and it is easy to decontaminate it with the decontaminating agents such as HCl and KHSO4.