Abstract: Example embodiments are directed to a method of fuel bundle design, core design, or combined fuel and core design, to ensure Pellet Cladding Interaction (PCI) related fuel failures are mitigated. More specifically, example embodiments provide fuel and/or core designs that may be determined prior to operation of a nuclear power plant, or prior to production of fresh fuel bundles. The PCI optimized fuel/core designs may include some or all of seven PCI Evaluation Methods which may be incorporated into existing nuclear reactor simulation programs. PCI optimized fuel and/or core design enhances fuel reliability, allows faster beginning-of-cycle (BOC) startups and faster middle-of-cycle (MOC) sequence exchanges to maximize plant performance, and minimizes ramping restrictions, thereby maximizing nuclear power plant performance.

Abstract: In a nuclear reactor core, control blades form discrete control blade groups forming a core pattern including first and second main groups, respectively, symmetrically and asymmetrically arranged about the core. Each main group has first and second sub-groups, each sub-group at each control blade location within the core being located alternately in orthogonally-related X and Y directions in plan view of the core. The first sub-group of the first main group includes an operational sub-group. The blades of the first and second main groups are used simultaneously. The blades of the second main group are used only as shallow blades. The blades of the first main group are movable into deep or shallow positions from withdrawn positions. Each fuel bundle operates without an adjacent control blade for a time period twice as long as any previous period of operation with an adjacent control blade inserted into the core. Any one control blade is fully withdrawn for two consecutive periods after insertion.