Nuclear fuel assembly with an integrated passive safety device
AssigneeCommissariat a l'Energie Atomique
InventorGuy Lemercier
Life of this patent
Estimating the term…
Abstract
Certain of the nuclear fuel assemblies contained in a fast neutron nuclear reactor core have an integrated passive safety device. More specifically, said device is constituted by an annular block (48) forming at least the lower part of the upper neutron protection (42) of the assembly. The block (48) is formed by elements (50) of a neutron-absorbing material, embedded in a matrix (52) meltable at a temperature above the temperature of the sodium during the normal operation of the reactor. A perforated, inner envelope (54) mechanically secures the block (48), whilst enabling the elements (50) to drop in the assembly following the melting of the matrix (52).
Claims8
Nuclear fuel assembly having an integrated passive safety device, comprising an external tubular envelope in which are located, starting from the top, an upper neutron protection and a bundle of nuclear fuel needles, the passive safety device including elements made from a neutron-absorbing material, normally maintained above the bundle of nuclear fuel needles by meltable means, the latter automatically bringing about the dropping of said elements when the temperature exceeds a predetermined threshold, which is higher than the normal operating temperature, wherein the neutron-absorbing material elements are embedded in a matrix constituting said meltable means, in order to form an annular block constituting at least a lower part of the upper neutron protection.
Dependencies are inferred from the claim text.