Decontamination process

A small amount of one or more weakly acidic organic complexing agents are added to the reactor coolant and pH value adjusted to produce a decontaminating solvent which is circulated through the cooling system. The metal oxides are thereby dissolved off from the inner surfaces and the resulting metal ions and radionuclide ions are complexed. The coolant containing the complexed metal ions and radionuclide ions are passed through a strongly basic anion exchange resin bed which was previously saturated with a solution containing the same proportions of complexing agents and the same pH value as the decontaminating solution. As the decontaminating solution passes through the resin bed the metal complexed anions are exchanged for the metal ion-free anions in the bed whilst the metal ion-free anions in the solution pass through the bed. By this means the metal ions are removed and the decontaminating solution is regenerated. (orig./WI)