Flux Flattening in a Graphite Moderated Core

摘要

An axial flux flattening program was instituted at N Reactor to lower the peak to average flux from 1.45 to the 1.25-1.30 range. Axially varying fuel enrichments are being used to accomplish the reduced peaking. The flux flattening program objectives are to improve operational constraints, safety margins, nuclear material production, and to homogenize fluence impacts upon the graphite moderator for the rest of the reactor's life. Development of numerical methods and computer models to provide design information was key to the program's success. (ERA citation 12:013486)