Reactor core for a light water cooled reactor, fuel assembly and control rod
AssigneeHitachi, Ltd.
InventorsRenzo Takeda, Motoo Aoyama, Masanao Moriwaki
Life of this patent
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Abstract
A reactor core for a boiling water reactor, a fuel assembly and a control rod intended for Pu multi-recycling at a breeding ratio of about 1.0, or 1.0 or more while keeping the economical or safety performance to the same level as in a boiling water reactor now under operation. The reactor has an effective water-to-fuel volume ratio of 0.1 to 0.6 by the combination of a dense lattice fuel assembly constituted of fuel rods formed by adding Pu to degraded uranium, natural uranium, depleted uranium or low concentrated uranium, and having coolants at a high void fraction of 45% to 70% and a cluster-type, Y-type or cruciform control rod.
Claims28
A reactor core for a boiling water reactor having fuels comprising uranium enriched with plutonium or plutonium and actinoid nuclides, wherein an average void fraction for the reactor core during operation at 50% or more rated power is from 45% to 70% and a length of a portion having an average enrichment of fissionable plutonium of 6 wt % or more along a horizontal cross section of a fuel assembly is between 40 cm and 140 cm in the direction of the height of the reactor core, whereby a breeding ratio of about 1.0 or more and a negative void coefficient are achieved.
A fuel assembly having fuels comprising uranium enriched with plutonium or plutonium and actinoid nuclides, wherein an effective water-to-fuel volume ratio is between 0.1 and 0.6 and a length of a portion having an average enrichment of fissionable plutonium of 6 wt % or more along a horizontal cross section of the fuel assembly is between 40 cm and 140 cm in the direction of the height of the fuel assembly, whereby a breeding ratio of about 1.0 or more is achieved.
A control rod to be inserted between fuel assemblies loaded to a reactor core for a boiling water reactor, wherein wings are arranged such that each spacing between the wings is 120 degrees and center lines extending from the respective wings in a horizontal cross section of the control rod constitute a regular triangle.
A hexagonal fuel assembly in which fuel rods are arranged in a regular triangular lattice pattern so as to form three sets of fuel rod rows, each set of fuel rod rows being parallel with a pair of opposing sides of the hexaaonal fuel assembly and the number of rows in two sets of fuel rods being equal to each other and greater by one row than that of the remaining one set of fuel rod rows among the three sets of fuel rod rows.
Dependencies are inferred from the claim text.