An Interval Bound Algorithm of optimizing reactor core loading pattern by using reactivity interval schema

► We present a new Loading Pattern Optimization method - Interval Bound Algorithm (IBA). ► IBA directly uses the reactivity of fuel assemblies and burnable poison. ► IBA can optimize fuel assembly orientation in a coupled way. ► Numerical experiment shows that IBA outperforms genetic algorithm and engineers. ► We devise DDWF technique to deal with multiple objectives and constraints.