Global Nuclear Fuel - Americas, LLC

John Patrick Rea

David Joseph Kropaczek

Mehdi Asgari

Nuclear fuel assemblies include at least one fluence control structure for use in a nuclear reactor core with other nuclear fuel assemblies. Such flux-limiting assemblies and structures may be positioned outside of or around the other nuclear fuel assemblies in the core so as to reduce neutron flux beyond the fluence controlled nuclear fuel assemblies, and fluence control structures may be positioned at an outside edge of the core. Fluence control structures limit neutron flux with non-fuel materials in structures like fuel rods and inserts, channels, shield curtains, etc. at particular positions in fuel assemblies. An engineer may select and/or install fluence-limiting fuel assemblies with flux-limiting characteristics in cores having neutronics profiles expected to benefit from such flux limitation.

Nuclear reactor fluence reduction systems and methods

In a method for improving the energy generating output of a nuclear reactor containing one or more fuel rods in one or more fuel rod bundles while satisfying a maximum subcritical banked withdrawal position (MSBWP) reactivity limit, enrichments of individual fuel rods in an axial cross-section of a lattice being evaluated at the top of the fuel bundle are ranked, and the fuel pins of the highest ranked rod location in the lattice are replaced with pins containing natural uranium. A core simulation is then performed to determine whether there is any margin to a MSBWP reactivity limit. For each lower ranked candidate rod position, the pin replacing and core simulation functions are repeated until no rod location violates the MSBWP reactivity limit, so as to achieve a desired lattice design for the top of the fuel bundle.

Method for improving energy output of a nuclear reactor, method for determining natural uranium blanket layer for a fuel bundle, and a fuel bundle having a variable blanket layer

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Wilmington, NC, United States of America

John Patrick Rea