Conductive Inserts to Reduce Nuclear Fuel Temperature

Technology Licensing Opportunity - This is not a procurement. Researchers at INL have found that placement of novel conductive inserts with UO2 fuel pellets will dissipate heat efficiently, allowing the fuel to operate at much lower temperature. The inserts act as cooling fins, producing large peak temperature drops in the fuel. One design incorporates six radial fins issuing from the center of the pellet. Among the scenarios analyzed, using molybdenum resulted in a peak temperature drop of 842 C at a linear heat generation rate of 500 W/cm. The second design involves thin alternating discs of molybdenum (50 microns) sandwiched between thin discs of UO2 (95 microns). In this scenario, the temperature drop was even more significant, 995 C at 500 W/cm. In both scenarios, only 5% of the UO2 volume was taken up by the thermal conductors. While we performed a variety of parametric analyses on factors such as thermal conductivity of the inserts, the geometry and volume of thermal conductors, the two designs described provide significant temperature reductions while taking up very little UO2 volume. These novel designs would benefit not only SMR and micro-reactor applications at enrichments greater than 5%, but also could benefit uprates and increased burnups at the current commercial limit of 5% enrichment, because of sustained thermal conductivity throughout the lifetime of the fuel. Our results point to the need for irradiation studies and further analyses, and their prompt communication can accelerate developments across these research fronts. Experimental and modeling efforts are underway. Idaho National Laboratory (INL), managed and operated by Battelle Energy Alliance, LLC (BEA), is offering the opportunity to enter into a collaborative research agreement, potentially leading to an exclusive license, to commercialize this technology. [U.S. Patent Application No. 16/661,398, October 23, 2019.]