Development of Process Flowsheet for Separation of Tellurium-125m from Antimony-125 and Production of Pilot Sample of Tellurium-125m Generator
Tech Area / Field
- FIR-ISO/Isotopes/Fission Reactors
- FIR-FUC/Fuel Cycle/Fission Reactors
3 Approved without Funding
Khlopin Radium Institute, Russia, St Petersburg
- Los Alamos National Laboratory, USA, NM, Los-Alamos
Project summaryThis project is going to continue the ISTC Project no. 1306 “Development of Methods for Antimony-125 Recovery from Spent Fuel and Separation of Tellurium-125m from Antimony-125 for Production of Tellurium-125m Radionuclide Generator”. In the framework of this study we developed the procedure of recovery and purification of antimony-125 from spent nuclear fuel wastes and obtained the preliminary results on separation of tellurium-125m from antimony-125 on model solutions.
Tellurium-125m can be used in various areas of science and technology, and also in medical sources for tissue therapy as an alternative to iodine-125. In addition, sources based on tellurium-125m are widely used in nuclear -resonance spectroscopy. According to its radiation characteristics, tellurium-125m is suitable radionuclide for producing sealed sources for X-ray fluorescence analysis. Carrier-free tellurium can be used in other fields. High-power sources based on tellurium-125m exhibit the phenomena characteristic of g-laser. For production of such sources, it is a need to have such concentration of tellurium-125m nuclei, which can be produced by the reaction (n, g) in a matrix enriched with tellurium-124 at the flux density of thermal neutrons approximately 1022 neutrons per 1 cm2. In so doing, the activity of tellurium-125m should be no less than 10 Ci. Hence, at present this problem can be solved only by development of high-power sources based on fission antimony-125 recovered from spent nuclear fuel wastes (after three-year storage one kilogram of spent nuclear fuel of the WWR type reactors contains approximately 4.2 Ci of antimony-125). Thus, spent nuclear fuel wastes are inexhaustible source of antimony-125. In this case, the samples of fission antimony should be significantly cheaper than the reactor samples, especially, in production of this radionuclide in the industrial scale. The use of the present procedures of radiochemical separation of antimony-125 and tellurium-125m involves some problems for regular production of large amounts of tellurium-125m.
As a result of the studies performed in the framework of the ISTC project no. 1306 we developed the procedure of recovery of antimony-125 from spent nuclear wastes. The possibility of recovery of significant amounts of antimony-125 from various processing solutions on inorganic sorbent was demonstrated. Even in the sorption stage antimony is separated from uranium, alkali, alkaline earth, and rare-earth elements, which are not sorbed under these conditions and are completely separated in washing. The presence of the products formed in corrosion of chemical apparatus (Fe, Cr, Ni, and Co) does not noticeably affect antimony sorption. The yield of antimony is approximately 85% of the initial amount. The experiments were carried out on both model and real processing solutions.
The results of experiments on separation of tellurium-125m and antimony-125 showed the fundamental possibility of producing high-power generator of tellurium-125m. Using various procedures of separation (sorption, electrochemical, thermochromatographic, etc.) we obtained preliminary results on model solutions with a high separation factor for the above pair and the yield of tellurium-125m approximately 80% of the amount to be accumulated.
The main objects of the project are:
- Optimization of the conditions of antimony-125 recovery from the solutions formed in processing of nuclear fuel as applied to hot cells.
- Development of process flowsheet for separation of tellurium-125m from antimony-125.
- Production of pilot sample of tellurium-125m generator with the power of approximately 1 Ci.
The results of this study and experiments under conditions of hot cells will enable us to recommend the developed process flowsheet on recovery of antimony-125 from spent nuclear wastes and separation of tellurium-125m from antimony-125 for testing under real processing conditions and production in commercial scale using wastes of radiochemical plants both in Russia and abroad.