Technetium behaviour in Boom Clay – a laboratory and field study

Abstract

Summary This paper describes a study of technetium solubility and migration under chemical conditions representative of those prevailing in a Boom Clay environment. Laboratory and in situ measurements yielded similar aqueous concentrations of technetium, of about 1×10 −8 mol dm −3 , close to the concentrations measured for hydrated technetium(IV) oxide TcO 2 ·1.6H 2 O in the solubility studies. From fitting the curves of the Tc concentrations as function of time, distribution coefficient (K d ) values were estimated to lie between 0.8 cm 3 g −1 and 1.8 cm 3 g −1 . Exposure of the system at 80 °C and to γ-radiation dose rates of several hundred Gy h −1 resulted in only minor differences in behaviour.