New approach to find the equilibrium cycle in PWR reactors using genetic algorithms

•Methodology for performing in-core fuel management PWR, using genetic algorithms.•Approach structured to find the equilibrium cycle of the Almaraz II reactor.•The equilibrium cycle reached all the physical conditions provided, lasting 240 EFPD.•The cycle has an average discharge burnup of 28.93 MWd/kgHM. This work presents a methodology applied for performing in-core fuel management PWR (ICFM), using genetic algorithms (GAs). A system was developed in which the GAs interact directly with a reactor physics code created for this purpose. The nodal code, called NOD2ABC, is responsible for providing the neutron characteristics of the reactor that one wants to carry out the ICFM and sending them to the GAs to optimize them, based on some criteria. This code was developed in 2-D and uses the Nodal Expansion Method (NEM). The reference reactor of the Central Nuclear Almaraz II, made available by the International Atomic Energy Agency (IAEA), was chosen and used in this work with the objective of qualifying and validating all the methodology used in the ICFM. The Assemblies of Almaraz II were modeled using the SCALE 6.0 system, developed by the Reactor and Nuclear Systems Division (RNSD), of the Oak Ridge National Laboratory (ORNL), with the purpose of generating the homogenized multigroup cross sections applied in the implemented nodal code. A new ICFM approach, using GAs, was structured to find a possible equilibrium cycle of the modeled reactor. The equilibrium cycle found reached all the physical conditions provided, lasts 240 days with the reactor operating at full power and has an average discharge burnup of 28.93 MWd/kgHM.