5 results about "Neutron moderator" patented technology

A radioisotope production capsule is described. Each capsule includes generally an inner container for housing one of a target material and a neutron moderator, an outer container surrounding the inner container for housing the one of the target material and the neutron moderator not housed by the inner container, and cladding for isolating the target material from the neutron moderator. One or more modular capsules are placed in each of a plurality of plug fingers. Each single plug finger loaded with one or more capsules is inserted into a guide thimble of an array of guide thimbles in a fuel assembly.

The application discloses a neutron gamma detector with high dynamic range and time resolution, comprising: a plurality of layers of detection units, a plurality of neutron moderators and a detector shell; each detection unit is arranged along the axis of the detector shell, and a neutron moderator is arranged between each detection unit; the detection unit comprises a neutron / gamma sensitive scintillator array, a photomultiplier tube array and a preamplifier array, and each layer of neutron / gamma sensitive scintillator array is matched with one layer of photomultiplier tube array and one layer of preamplifier array. The detector utilizes the multiple layers of neutron moderators to form the gradient of the neutron and gamma ray detection efficiency of each layer of scintillator, the neutron / gamma sensitive scintillator array matched with the photomultiplier tube array and the preamplifier array can measure and obtain a pulse count matrix, and then the neutron and gamma count rate at each layer of detector can be extracted. Meanwhile, the time resolution and dynamic range are improved based on the structural design of the detector.

The application relates to a high-temperature-resistant composite neutron moderator material and a manufacturing method thereof, and belongs to the nuclear power field. The manufacturing method of the high-temperature-resistant composite neutron moderator material comprises the following steps: determining the hydrogen partial pressure of a metal hydride at a working temperature, establishing a moderator material particle model comprising a metal hydride core, a buffer layer and a SiC sealing layer and calculating the stress borne by the SiC sealing layer at the working temperature; calculating the allowable stress of the SiC sealing layer at the working temperature and adjusting the moderator material particle model according to the allowable stress to obtain a corrected moderator material particle model; and manufacturing a high-temperature-resistant composite neutron moderator material finished product based on the corrected moderator material particle model. The method can be used for manufacturing a neutron moderator material with good stability and reliability at a high temperature, and improves the safety and reliability of a commercial nuclear power plant reactor.

A nuclear fission reactor comprising a passive thermal shut-down device, and a reactor core containing fissile fuel. The passive thermal shutdown device comprises a reservoir and a Pythagorean syphon. The reservoir is in thermal communication with the reactor core, and containing a neutron poison material which has a free surface. The Pythagorean syphon has an inlet within the reservoir, an outlet in fluid communication with the reactor core. When the neutron poison material overtops the syphon due to thermal expansion, the neutron poison material flows through the Pythagorean syphon and into the reactor core. Also provided are nuclear fission reactors having passive thermal shutdown devices using a Pythagorean syphon to control the flow of fissile fuel, neutron moderators, or neutron reflectors.

This application provides a spherical bed fuel molten salt breeder reactor system and its operation method. The system includes: a reactor body containing a solid spherical bed, the solid spherical bed comprising solid fuel spheres and neutron moderator spheres. The solid fuel spheres are used to initiate fission reactions to produce neutrons and completely confine fission products inside the spheres. The neutron moderator spheres are used to moderate the neutrons. A breeder cooling circuit connected to the reactor body circulates a liquid molten salt containing thorium but not fissile nuclides. When the liquid molten salt flows through the solid spherical bed, thorium-232 in the liquid molten salt absorbs neutrons and is then multiplied into uranium-233 or its precursors. An online chemical processing subsystem connected to the breeder cooling circuit is used to extract and enrich uranium-233 or its precursors from the liquid molten salt. A fuel loading and unloading system connected to the reactor body is used to adjust the composition ratio of solid fuel spheres and neutron moderator spheres in the solid spherical bed.