Abstract: A method for the treatment of radioactive evaporator concentrates from the evaporation system of nuclear plants comprises the steps of (a) freeing the evaporator concentrates from undissolved components, (b) crystallizing the sodium sulfate contained in the evaporator concentrates as Glauber's salt (Na2SO4.10 H2O) on an immersion cooler, (c) recrystallizing the Glauber's salt deposited on the immersion cooler, (d) optionally, repeating the recrystallization step (c) once or several times, (e) separating essentially inactive sodium sulfate from the process, and (f) recycling the depleted evaporator concentrates of step (a) to the evaporation system.

Abstract: Phosphoric acid solution used in the decontamination of radioactive metal articles is reacted with oxalic acid to precipitate the iron oxalate which is then pyrolyzed to form a mixture of oxides in small volume for storage as a radioactive waste. The solution from which the oxalate is removed is evaporatively concentrated and reused for decontamination.