Experimental Testing of Annular Target Surrogates for the Production of Molybdenum-99

Technetium-99m (Tc-99m) is a diagnostic radiopharmaceutical that is currently used about 100,000 times daily for diagnostic imaging procedures globally [1]. The parent isotope for Tc-99m is molybdenum-99 (Mo-99), most commonly obtained through the irradiation of high enriched uranium (HEU). In accordance with the Department of Energy’s Global Threat Reduction Initiative (GTRI), an effort is underway to develop a process to produce Mo-99 using low enriched uranium (LEU). One method utilizes LEU cast in the form of a metal foil as opposed to current powder based dispersion designs for HEU. New high-volume production LEU target concepts need to be analyzed to assure safe, reliable operation during all stages of production as use of a foil requires a significant modification to the current target design.Analytic and numeric models have been built to simulate the thermal-mechanical behavior of LEU-foil based targets under irradiation conditions. Experimental testing is being used to validate the models. Heating conditions are controlled by heater placement and cooling water circulation to place the target interfaces into controlled states of compression and tension. Thermocouples are used to measure the temperature at key locations so that the thermal contact resistance can be evaluated and compared with the predictions.© 2012 ASME