Since highly enriched targets were substituted by low-enriched targets, the same molybdenum yield doubles the the resulting aqueous, medium-level radioactive waste to an annual volume of up to 15,000 liters worldwide – which furthermore has to be cemented to be suitable for final disposal, so that in the end radioactive waste with a volume of 375,000 liters is produced every year.

The solution: Get rid of the water
To alleviate this problem, Chemnitz and his colleague Riane Stene developed a new method for extracting Mo-99 without the use of aqueous chemistry.
In collaboration with the fluorine chemistry group at Philipps University of Marburg, the researchers developed a system in which the uranium-molybdenum test plates react with nitrogen trifluoride in a plasma. These plates had the same molybdenum content as would later be present in actual irradiated targets.

Finally, they separated the excess uranium from the molybdenum via a light-controlled reaction. The separation of the two elements in this manner is every bit as efficient as the sodium hydroxide treatment performed in the first step of the conventional reprocessing procedure – with the notable exception that it produces no aqueous waste.

Only six major research reactors produce molybdenum-99
"Currently, six major irradiation facilities worldwide produce Mo-99. Of these research reactors, four are over 40 years old, which leads to unforeseen repairs and associated shutdowns – as has already happened in the recent past. That is why we are proud that the FRM II, together with the French Jules-Horowitz reactor, will be able to secure the European demand for Mo-99 in the future," says Tobias Chemnitz.

TUM has submitted a patent application for the process. Regardless that further development work is still needed, Chemnitz is confident that this novel approach will provide a viable alternative to established processes in the medium term.

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