Separation of actinium from an irradiated source material including thorium

A method of manufacturing a radioisotope of actinium comprising:

• providing an irradiated source material including thorium, the irradiated source material derived from fission product material created by the fissioning of a nuclear fuel;
• placing the irradiated source material including thorium in a containment vessel;
• storing the source material for a period of time thereby allowing some of the irradiated source material to decay into radioisotopes including at least one radioisotope of actinium;
• after storing the source material for the period of time, injecting the containment vessel containing the radioisotopes with supercritical carbon dioxide containing a ligand that selectively forms a metal complex with the at least one radioisotope of actinium but does not form a metal complex with the thorium, thereby forming a supercritical carbon dioxide mixture containing an amount of actinium radioisotope complexes;
• removing the supercritical carbon dioxide mixture containing an amount of actinium radioisotope complexes;
• and
• separating at least some of the actinium radioisotope complexes from the supercritical carbon dioxide mixture to provide a separation fraction containing the at least one radioisotope of actinium.