In core fuel management in PWR reactors using genetic algorithms

Resumo

This work presents a methodology applied to perform an in core fuel management (ICFM) in pressurized
water reactors (PWR) using genetic algorithms (GA’s). The ICFM consists of defining a recharge pattern during
the reactor's operational cycles, that is, finding the best arrangement of fuel elements (FEs), new and partially
burned, which optimizes the reactor's performance, meeting its safety criteria. The proposed methodology is based
on developing an interface in which the GA can interact with the reactor physics simulation code, which has the
neutronic characteristics of each FE and must be reliable and fast. Then, it was necessary to develop, using a
technique already consolidated in the literature, a coarse-meshed nodal code that numerically solves the multigroup
diffusion equation for two energy groups, fast and thermal neutrons, in two dimensions. In this type of code, each
FE, represented by a node, must be homogenized and represented by its multigroup constants, for each reactor
burn step. The SCALE system, developed by The Reactor and Nuclear Systems Division (RNSD) of the Oak
Ridge National Laboratory (ORNL), was used to calculate these constants. All qualification and validation of the
results obtained from the homogenization of the EC's by SCALE together with the nodal code were carried out
comparing them with the benchmark of Central Nuclear Almaraz II provided by the International Atomic Energy
Agency (IAEA).