A performance investigation of the GE-14 nuclear fuel bundle with weighted objective functions

Abstract

The GE-14 fuel bundle design was deemed to be state of the art at its introduction in the 1990s. With the recent advancements in nuclear reactor design and fuel fabrication technology, GE-14 fuel design may find more room for improvement. In normal operations of nuclear reactors, GE-14 fuel assemblies experience non-uniform critical power ratio fluctuations axially, which inhibits optimal performance. This thesis research focuses on the characterization of GE-14 fuel bundle performance and applying weighted objective functions to optimize the fuel bundle design to permit greater performance. Using the Monte Carlo code, MCNP6, it was found that there is a strong axial peak of the GE-14 bundles in the power shaping zone of the bundle. This peak becomes a hot spot for any reactor thermal limits and therefore limits the amount of power, which can be produced in the bundle. The use of objective functions allowed for the weighted optimization of all considered parameters. The functions to optimize include the lattice enrichment, gadolinium content, multiplication factor, and power peaking factors. With the objective functions the optimization level was reduced from a value of 8.257 to 3.318. This was accomplished by minimizing both enrichment and gadolinium content, reducing the power peaking factors, and increasing reactivity.