Patent Number: 
Section: claims

1. A method of producing cesium-131, comprising:dissolving at least one non-irradiated barium source in water or a nitric acid solution to produce a barium target solution;subjecting the barium target solution to neutron radiation to produce cesium-131; andremoving the cesium-131 from the barium target solution. 2. The method of claim 1, wherein dissolving at least one non-irradiated barium source in water or a nitric acid solution comprises dissolving at least one nonirradiated barium compound selected from the group consisting of barium carbonate (BaCO3), barium chlorate (Ba(ClO3)2.H2O), barium chloride (BaCl2), barium formate (Ba(CHO2)2), barium fluoride (BaF2), barium nitrate (Ba(NO3)2), barium metal, and barium oxide (BaO) in the water or nitric acid solution. 3. The method of claim 1, wherein dissolving at least one non-irradiated barium compound in water or a nitric acid solution comprises dissolving at least one of a non-irradiated, natural barium compound and a non-irradiated, enriched barium compound in the water or nitric acid solution. 4. The method of claim 1, wherein dissolving at least one non-irradiated barium source in water or a nitric acid solution to produce a barium target solution comprises dissolving an amount of the at least one non-irradiated barium source in the water or nitric acid solution to provide a concentration of the at least one non-irradiated barium source of greater than or equal to approximately 0.5 M. 5. The method of claim 1, wherein dissolving at least one non-irradiated barium source in water or a nitric acid solution comprises dissolving an amount of the at least one non-irradiated barium source in the water or nitric acid solution to provide a concentration of the at least one non-irradiated barium source of from approximately 0.5 M to approximately 1 M. 6. The method of claim 1, wherein dissolving at least one non-irradiated barium source in water or a nitric acid solution comprises dissolving the at least one nonirradiated barium source in from approximately 1 M to approximately 3 M nitric acid. 7. The method of claim 1, wherein removing the cesium-131 from the barium target solution comprises flowing the barium target solution through a separation device comprising a calixarene compound. 8. A method of producing cesium-131, comprising:irradiating a barium target solution comprising nitric acid and at least one non-irradiated barium-130 compound to produce cesium-131;complexing the cesium-131 with a calixarene compound; andseparating the cesium-131 from the irradiated barium target solution. 9. The method of claim 8, wherein irradiating a barium target solution comprising at least one non-irradiated barium-130 compound comprises irradiating the barium target solution comprising at least one naturally occurring barium-130 compound or at least one barium compound enriched in barium-130. 10. The method of claim 8, wherein separating the cesium-131 from the irradiated barium target solution comprises removing the cesium-131 by liquid-liquid extraction. 11. The method of claim 8, wherein separating the cesium-131 from the irradiated barium target solution comprises removing the cesium-131 by extraction chromatography. 12. A method of producing cesium-131, comprising:irradiating a target solution comprising barium and nitric acid to produce an irradiated barium target solution;enabling the irradiated barium target solution to decay for an amount of time sufficient to produce cesium-131; andcontinuously separating the cesium-131 from the irradiated barium target solution. 13. The method of claim 12, wherein irradiating a barium target solution to produce an irradiated barium target solution comprises exposing the barium target solution to neutron irradiation. 14. The method of claim 12, wherein continuously separating the cesium-131 from the irradiated barium target solution comprises continuously circulating the irradiated barium target solution through an isotope production system. 15. The method of claim 12, wherein continuously separating the cesium-131 from the irradiated barium target solution comprises continuously contacting the irradiated barium target solution with a calixarene extractant solution comprising at least one calixarene compound, at least one modifier, and a diluent. 16. The method of claim 12, wherein continuously separating the cesium-131 from the irradiated barium target solution comprises complexing the cesium-131 with a calixarene compound selected from the group consisting of: calix[4]arene-bis-(tert-octylbenzo)-crown-6, 1,3-alternate-25,27-di(octyloxy)calix[4]arenebenzocrown-6, 1,3-alternate-25,27-di(decyloxy)calix[4]arenebenzocrown-6, 1,3-alternate-25,27-di(dodecyloxy)calix[4]arenebenzocrown-6, 1,3-alternate-25,27-di(2-ethylhexyl-l-oxy)calix[4]arenebenzocrown-6, 1,3-alternate-25,27-di(3,7-dimethyloctyl-1-oxy)calix[4]arenebenzocrown-6, and 1,3-alternate-25,27-di(4-butyloctyl-l-oxy)calix[4]arenebenzocrown-6. 17. The method of claim 12, wherein continuously separating the cesium-131 from the irradiated barium target solution comprises continuously flowing the irradiated barium target solution through an extraction column comprising at least one calixarene compound supported on a solid support. 18. A method of producing cesium-131, comprising:dissolving at least one non-irradiated barium source in nitric acid to produce a barium target solution;irradiating the barium target solution in a nuclear reactor to produce cesium-131; andflowing the irradiated barium target solution through at least one separation device to remove the cesium-131. 19. The method of claim 18, further comprising continuously flowing the irradiated barium target solution through the nuclear reactor and the at least one separation device.