The present invention relates to a low-activation concrete comprising high-purity limestone aggregate and white cement, or high-purity limestone aggregate and aluminous cement. The low-activation concrete reduces the content of Europium, Cobalt and Cesium, as well as the content of elements such as Aluminium, Sodium, and Magnesium, when compared to standard concrete compositions and compositions for low-activation concrete already known in the art. The use of the low-activation concrete for forming an interior wall of a particle accelerator vault is provided as well.

This geopolymer molding production method comprises: a mixing step (S1) for mixing a first material containing aluminum and silicon with a hydrate of an alkali stimulant containing a hydrate of an alkaline hydroxide and/or a hydrate of an alkaline silicate; a compaction step (S2) for compacting the mixture obtained in the mixing step (S1) into a compacted mixture; and a curing step (S3) for curing the compacted mixture.

The novel process enables designing of raw materials and processing parameters, enabling synergistic and simultaneous chemical reactions among the various reactants of the design mix of chemical precursor of brine sludge which includes barium sulphate, magnesium hydroxide, calcium carbonate, sodium chloride, silica, aluminum containing compounds necessary for developing highly efficient shielding phases leading to homogenous matrix of shielding materials.

A sacrificial concrete for a core catcher and a preparation method thereof are provided. The sacrificial concrete includes raw materials in parts by weight as follows: cement, 575˜625 parts; a quartz sand, 1200˜1300 parts; a hematite ore, 700˜800 parts; water, 200˜220 parts; a water reducing agent, 7˜10 parts; and strontium oxide, 0˜10 parts. The process of the preparation method is simple, and the sacrificial concrete with excellent performances of fluidity, strength and high-temperature resistance can be prepared by the known mixing technology. The sacrificial concrete can reduce releasing of radioactive substances .sup.89Sr and .sup.90Sr, so as to improve safety of nuclear power plants in case of a severe accident. Moreover, the sacrificial concrete can be used not only in a core catcher of current third generation nuclear power plant, but also in a core catcher of future fourth generation nuclear power plant, and has widespread engineering application value.

The method includes forming an inner monolithic layer from crystals of beta phase stoichiometric silicon carbide on a carbon substrate in the form of a rod by chemical methylsilane vapor deposition in a sealed tubular hot-wall CVD reactor. The method further includes forming a central composite layer over the inner monolithic layer by twisting continuous beta phase stoichiometric silicon carbide fibers into tows, transporting the tows to a braiding machine, and forming a reinforcing thread framework. A pyrocarbon interface coating is built up by chemical methane vapor deposition in a sealed tubular hot-wall CVD reactor. Then, a matrix is formed by chemical methylsilane vapor deposition in the reactor. A protective outer monolithic layer is formed from crystals of beta phase stoichiometric silicon carbide over the central composite layer by chemical methylsilane vapor deposition in a CVD reactor. And then the carbon substrate is removed from the fabricated semi-finished product.

The present invention provides a bidirectional energy-transfer system comprising: a thermally and/or electrically conductive concrete, disposed in a structural object; a location of energy supply or demand that is physically isolated from, but in thermodynamic and/or electromagnetic communication with, the thermally and/or electrically conductive concrete; and a means of transferring energy between the structural object and the location of energy supply or demand. The system can be a single node in a neural network. The thermally and/or electrically conductive concrete includes a conductive, shock-absorbing material, such as graphite. Preferred compositions are disclosed for the thermally and/or electrically conductive concrete. The bidirectional energy-transfer system may be present in a solar-energy collection system, a grade beam, an indoor radiant flooring system, a structural wall or ceiling, a bridge, a roadway, a driveway, a parking lot, a commercial aviation runway, a military runway, a grain silo, or pavers, for example.

A radiation shield unit, which shields against neutron rays, X-rays, and γ-rays, contains 10 vol % or more and 90 vol % or less of gadolinium.

A self-supporting inorganic and radiation-hard neutron shielding panel for use in absorbing thermal neutrons. The panel is constructed substantially of concrete and includes a high level of boron by weight to enhance the absorption of thermal neutrons. A layer of radiation-resistant fiber reinforcement within the panel enables production of a thin, strong panel that is self-supporting and easily transportable. Mounting means are included on the panel to facilitate easy mounting on a wall or similar surface. The panels are constructed entirely of inorganic materials and include at least 58% boron by weight to maximize their effectiveness in shielding against thermal neutrons. Further disclosed are methods for forming the neutron-shielding panels.

The invention discloses a strontium ferrite-based sacrificial mortar and its preparation method, the strontium ferrite-based sacrificial mortar mainly comprises 720-1000 parts of sulphoaluminate cement, 100-300 parts of strontium ferrite, 600-650 parts of quartz sand, 400-450 parts of water and 0.01-35 parts of superplasticizer. The preparation process is simple, and the strontium ferrite-based sacrificial mortar can be prepared by using a conventional forced single horizontal shaft concrete mixer. The obtained mortar has excellent working performance, compressive strength and corrosion resistance. It can be used in the current third and future fourth generation nuclear power plant core catchers, and has obvious engineering application value.

Aspects of the present disclosure provide for cement, cement paste, cementitious paste, cementitious mortar, and concrete, methods of making cement, cement paste, cementitious paste, cementitious mortar, and concrete, structures incorporating the concrete, and the like, where the cement, cement paste, cementitious paste, cementitious mortar, and the concrete include elemental boron and/or one or more boron compounds (e.g., boron-doped cement, cement paste, cementitious paste, cementitious mortar, and concrete). The boron and/or a boron compound can be homogeneously distributed throughout the cement, cement paste, cementitious paste, cementitious mortar and/or concrete.