Actinides recycling assessment in a thermal reactor

• Actinides recycling is assessed using BWR fuel assemblies.
• Four fuel rods are substituted by minor actinides rods in a UO2 and in a MOX fuel assembly.
• Performance of standard fuel assemblies and the ones with the substitution is compared.
• Reduction of actinides is measured for the fuel assemblies containing minor actinides rods.
• Thermal reactors can be used for actinides recycling.

Actinides recycling have the potential to reduce the geological repository burden of the high-level radioactive waste that is produced in a nuclear power reactor. The core of a standard light water reactor is composed only by fuel assemblies and there are no specific positions to allocate any actinides blanket, in this assessment it is proposed to replace several fuel rods by actinides blankets inside some of the reactor core fuel assemblies. In the first part of this study, a single uranium standard fuel assembly is modeled and the amount of actinides generated during irradiation is quantified for use it as reference. Later, in the same fuel assembly four rods containing 6 w/o of minor actinides and using depleted uranium as matrix were replaced and depletion was simulated to obtain the net reduction of minor actinides. Other calculations were performed using MOX fuel lattices instead of uranium standard fuel to find out how much reduction is possible to obtain. Results show that a reduction of minor actinides is possible using thermal reactors and a higher reduction is obtained when the minor actinides are embedded in uranium fuel assemblies instead of MOX fuel assemblies.