SMR Core Depletion and Spent Fuel Characterization with Nodal Code Ants

Numerous emerging small modular pressurized water reactors rely on compensating core excess reactivity with control rods instead of soluble boron. The spent fuel characterization for these reactors requires detailed modeling of the irradiation due to the distortion of power and neutron spectrum in the vicinity of deeply inserted control rods. This paper presents a micro-depletion-based method implemented in nodal code Ants for calculating spent fuel inventory. The technique utilizes the Kraken reactor simulator framework developed at VTT Technical Research Centre of Finland for preparing group constant data and running coupled fuel cycle simulations. The work is based on calculating LDR lite first fuel cycle with Ants-Kharon-SuperFINIX coupling scheme where group constant data and homogenized microscopic cross sections are prepared with Serpent. Results from the fuel cycle are compared to a reference Serpent solution. The comparison shows that the microscopic depletion model in Ants can produce satisfactory inventory estimates on a core level. Further work contains assessing the advantages of the micro-depletion method over conventional methods and expanding the analysis to higher burnups.