SET OF FUEL ASSEMBLY FOR BOILING-WATER REACTOR, AND REACTOR CORE LOADED WITH THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a set of fuel assemblies for boiling-water reactor that has higher flexibility in operation than before and also increases safety in loading into an initial loading reactor core or a long-period cycle reactor core.SOLUTION: A set of fuel assemblies which are loaded in the same reactor core at the same time and are equal in assembly average enrichment to one another has at least two types differing in number of combustible poisoned fuel rods from each other. Further, types which are equal in number of combustible poisoned fuel rods include types which are mutually different in border position where axial combustible poison concentration changes with respect to at least one combustible poisoned fuel rod in a fuel rod group constituting each fuel assembly.