Method for the manufacture of Radium-225-containing material from Radium-226-containing materials by subjecting a starting material containing Radium-226 to neutron irradiation from a nuclear reactor to convert .sup.226Ra into Radium-225 to provide a Radium-225-containing material, characterised in that the neutron irradiation of Radium-226-containing starting material is performed in a moderated nuclear reactor; and the Radium-226-containing starting material is shielded with a thermal neutron absorption shield.

Provided is a body, a method for manufacturing the body and a method of using of the body for nuclear shielding in a nuclear reactor. The body may include boron, iron, chromium, carbon and tungsten.

A biological protection for closing an opening in a wall delimiting a radiation zone, this protection comprising at least one iris diaphragm with a base in the form of a flat disk carrying petals formed by plates having a triangular contour and made of a material protecting against ionising radiation. These petals are movable parallel to the base between an open state in which the petals delimit together a central aperture and a closed state in which the petals are closely joined to form together a continuous closed wall.

The present disclosure is directed to systems and methods useful for the construction and operation of a Modular Integrated Gas High-Temperature Reactor (MIGHTR). The MIGHTR includes a reactor core assembly disposed at least partially within a core baffle within a first high-pressure shell portion, a thermal transfer assembly disposed at least partially within a flow separation barrel within a second high-pressure shell portion. The longitudinal axes of the first high-pressure shell portion and the second high-pressure shell portion may be collinear. The reactor core assembly may be accessed horizontally for service, maintenance, and refueling. The core baffle may be flexibly displaceably coupled to the flow separation barrel. Coolant gas flows through the reactor core assembly and into the thermal transfer assembly where the temperature of the coolant gas is reduced. A plurality of coolant gas circulators circulate the cooled coolant gas from the thermal transfer assembly to the reactor core assembly.

Collimators and other components for use in neutron scattering experiments or to provide neutron shielding in nuclear reactors or accelerator based neutron sources are produced by additive manufacturing from multiple different types of material, such as boron carbide (B.sub.4C), steel, isotopically enriched boron carbide (.sup.10B.sub.4C), and blends thereof.

Provided is a body, a method for manufacturing the body and a method of using of the body for nuclear shielding in a nuclear reactor. The body may include boron, iron, chromium, carbon and tungsten.

A nuclear power plant comprises a nuclear reactor, the nuclear reactor comprising reactor fuel elements, a reactor vessel surrounding the nuclear reactor and a primary shield surrounding the reactor vessel. The reactor fuel elements are arranged between a first height and a second height above the first height. The primary shield comprises a base portion, an intermediate portion and a top portion. The base portion has an upper height below the first height and the base portion comprises concrete. The top portion has a lower height above the second height and the top portion comprises concrete. The intermediate portion is arranged vertically between the base portion and the top portion of the primary shield. The intermediate portion comprises at least one support structure and a matrix material containing tungsten or boron, and the least one support structure extends between the top portion and the bottom portion of the primary shield.

The present disclosure provides for cementitious shielding compositions, methods of making the cementitious shielding composition, structures incorporating the concrete cementitious shielding composition, and the like, where the cementitious shielding composition includes elemental boron and/or a boron compound, for example as boron particles. The boron particles can be homogeneously distributed throughout the cementitious shielding composition and can have a largest least dimension of about 100 microns or less. The present disclosure, in some aspects, can reduce or eliminate problems associated with minerals found in concrete aggregates, because those materials are degraded over time by neutron radiation, which leads to disorganized lattice structures, manifested as damage by radiation-induced volumetric expansion (RIVE), and potentially further damage from alkali-silica reaction (ASR).

Collimators and other components for use in neutron scattering experiments or to provide neutron shielding in nuclear reactors or accelerator based neutron sources are produced by additive manufacturing from neutron absorbing material, such as boron carbide (B.sub.4C) or isotopically enriched boron carbide (.sup.10B).

Collimators and other components for use in neutron scattering experiments or to provide neutron shielding in nuclear reactors or accelerator based neutron sources are produced by additive manufacturing from neutron absorbing material, such as boron carbide (B.sub.4C) or isotopically enriched boron carbide (.sup.10B).