ADVANCED FIRST CORE FUEL ASSEMBLY CONFIGURATION

摘要

An advanced initial core fuel configuration is for improving the fuel management efficiency and thus economics for a nuclear reactor. The advanced initial core fuel configuration includes a plurality of fuel assemblies having different average enrichments of uranium 235 and arranging the fuel assemblies in an initial core configuration structured to emulate a known equilibrium reload cycle core at least in terms of spatial reactivity distribution. The resulting average enrichment within the initial core ranges from below about 1.0 percent weight of uranium 235 to about 5.0 percent weight of uranium 235. An advanced lattice design is also disclosed.

主权项

1. An advanced first core for a nuclear reactor comprising:
an interior; a periphery; a plurality of new fuel assemblies which when configured in a first core of a pressurized water reactor that has a plurality of regions of fuel assemblies, emulate energy output and discharge burn-up of a corresponding plurality of regions that make up a target equilibrium reload cycle core, each of said regions comprising a plurality of equilibrium reload cycle core fuel assemblies, each of said new fuel assemblies having a vertical length and having not been previously irradiated in a reactor core, a majority of said new fuel assemblies having a different elemental make up than a corresponding one of the equilibrium reload cycle core fuel assemblies, said new fuel assemblies having different average enrichments of uranium 235 including high enrichment fuel assemblies and low enrichment fuel assemblies, wherein said first core is loaded by the method comprising: arranging said plurality of new fuel assemblies in a first core configuration of a pressurized water reactor based upon energy output and discharge burn-up data obtained for substantially all of the plurality of the regions that makeup the target equilibrium reload cycle core, in order to emulate said target equilibrium reload cycle core in terms of spatial reactivity distribution, said first core including the interior and the periphery, wherein said first core is entirely made up of said new fuel assemblies, wherein substantially all of said high enrichment fuel assemblies are loaded toward the interior of said first core, and wherein an advanced lattice design and associated structure are provided for at least some of said plurality of new high enrichment fuel assemblies of said first core having a plurality of sides in which there is no extended barrier which would prohibit cross flow of a coolant over the vertical length of said fuel assemblies, in order that lateral circulation of said coolant across said fuel assemblies is provided as said coolant moves vertically, with the advance lattice having a peripheral row of fuel rods extending around the sides of the fuel assembly and a number of interior rows of fuel rods wherein most of the fuel rods in the peripheral row have a lower enrichment than most of the fuel rods in the interior rows.