A method of constructing a space construction has a preparing step, a first mixing step, a second mixing step, a matrix layer building step, a three-dimensional fiber webs paving step, and a gamma ray screening layer building step. Prepare an agitator, a strengthening material, a composite material, multiple three-dimensional fiber webs, and multiple gamma ray screening elements. Mix the strengthening material and the composite material to form a first building material. Mix the multiple gamma ray screening elements and soil on a planet to form a second building material. Build at least one matrix layer with the first building material. Pave two three-dimensional fiber webs on the at least one matrix layer. Build at least one gamma ray screening layer adjacent to one of the two three-dimensional fiber webs with the second building material. A product constructed by the method is also provided.

A nuclear fuel includes uranium(IV) oxide (UO.sub.2) and manganese (Mn) as a dopant. The Mn dopant may be present in the fuel in an amount up to the solubility limit for Mn under a given set of conditions, for example, about 0.01 wt % to about 1 wt %. The nuclear fuel is substantially free of aluminum (Al). The nuclear fuel exhibits enhanced grain size development during sintering temperatures as low at 1400 K due to an increase in uranium sub-lattice vacancies induced by dissolution of the Mn dopant at interstitial defect sites. The Mn-doped nuclear fuel exhibits improved grain sizes at lower temperatures compared to Cr-, Al-, and undoped UO.sub.2, and therefore desirably exhibits lower fission gas release and higher plasticity, reducing the chances of fuel rod failure.

Ceramic composite materials that are reinforced with carbide fibers can exhibit ultra-high temperature resistance. For example, such materials may exhibit very low creep at temperatures of up to 2700 F. (1480 C.). The present composites are specifically engineered to exhibit matched thermodynamically stable crystalline phases between the materials included within the composite. In other words, the reinforcing fibers, a debonding interface layer disposed over the reinforcing fibers, and the matrix material of the composite may all be of the same crystalline structural phase (all hexagonal), for increased compatibility and improved properties. Such composite materials may be used in numerous applications.

The present invention relates to a modified red sludge or a modified bauxite residue and processes for producing same, and to a storage medium comprising a modified red sludge, a heat store comprising a storage medium and numerous uses of a It modified red sludge as storage medium, more particularly in a heat store system. The modified red sludge here contains the following components: haematite (Fe.sub.2O.sub.3), corundum (Al.sub.2O.sub.3), rutile (TiO.sub.2) and/or anatase (TiO.sub.2), quartz (SiO.sub.2), optionally perovskite (CaTiO.sub.3) and optionally pseudobrookite ((Fe.sup.3+, Fe2+).sub.2(Ti, Fe.sup.3+)O.sub.5) and/or nepheline ((Na,K)[AlSiO.sub.4]). A novel material is thus provided, and production thereof is described for use as storage medium in a sensitive energy storage system in the low-, medium- or high-temperature sector.

The invention relates to a composition which contains modified chromate-deficient red mud, comprising a mineral composition of10 to 50 wt. % of iron compounds,12 to 35 wt. % of aluminum compounds,5 to 17 wt. % of silicon compounds,2 to 10 wt. % of titanium dioxide,0.5 to 6 wt. % of calcium compounds,0 to 1 ppm of chromium (VI) compounds, andoptionally additional unavoidable impurities. The composition, in particular the modified chromate-deficient red mud, contains a poorly soluble reducing agent for Cr(VI). In this manner, an inexpensive chemical composition is provided in particular as an iteratively functioning long-term adsorbent for pollutants in liquid, gaseous, and solid milieu. The invention further relates to a method for producing same and to uses thereof.

A method for preparing low-background cement includes: uniformly mixing a seed crystal of cement, C.sub.4AF whiskers, and high-magnesium raw material to yield a first mixture, calcining the first mixture at 1400-1500 C., to yield a low-background clinker, the first mixture including 1.0-5.0 wt. % of the seed crystal of cement, 1.0-5.0 wt. % of the C.sub.4AF whiskers, and the balance is the high-magnesium raw material; and grinding a second mixture of the low-background clinker and gypsum, to yield low-background cement. The seed crystal of cement is a high-magnesium and low hydration heat clinker, has a specific activity of Ra-226 radioactive nuclides within 50 Bq/kg, and the MgO content of the clinker is between 4.0 wt. % and 5.0 wt. %, with 50 wt. % <C.sub.3S <55.0 wt. %; and the high-magnesium raw material has a MgO content between 2.5 wt. % and 3.0 wt. %.

A shielding material for shielding radioactive ray and preparation method thereof. The shielding material consists of water, a cementing material, a fine aggregate material, a coarse aggregate material and an additive, wherein the fine aggregate material consists of a borosilicate glass powder and a barite sand, and the coarse aggregate material consists of a barite. A content of boron element in the borosilicate glass powder accounts for 0.5%-1% of the total weight of the shielding material. A content of barium sulfate in the barite sand and the barite accounts for 71%-75% of the total weight of the shielding material. Other contents include water, the cementing material and the additive, and a sum of contents of all components is 100% total weight of the shielding material.

The cementitious material for a radioactive waste disposal facility includes base cement, and porous and amorphous silica powder. The amount of the silica powder in the entire cementitious material ranges from 35% to 65% on a mass basis.

A material in the form of an alveolar monolith consisting of a matrix of an inorganic oxide with a hierarchical and opened porosity comprising macropores, mesopores and micropores, said macropores, mesopores and micropores being interconnected, and nanoparticles of at least one metal cation exchange inorganic solid material being distributed in said porosity. A method for preparing this material and a method for separating a metal cation notably a cation of a radioactive isotope of a metal such as cesium using this material.

The present invention relates to a modified red mud/a modified bauxite residue and also to processes for the production thereof and to a storage medium comprising a modified red mud, to a heat storage means comprising a storage medium and to numerous uses of a modified red mud as storage medium, in particular in a heat storage means. The modified red mud contains the following components: haematite (Fe.sub.2O.sub.3), corundum (Al.sub.2O.sub.3), rutile (TiO.sub.2) and/or anatase (TiO.sub.2), quartz (SiO.sub.2), optionally perowskite (CaTiO.sub.3) and optionally pseudobrookite ((Fe.sup.3+,Fe.sup.2+).sub.2(Ti,Fe.sup.3+)O.sub.5), nepheline ((Na,K)[AlSiO.sub.4]) and/or hauynite ((Na,Ca).sub.4-8[Al.sub.6Si.sub.6O.sub.24(SO.sub.4)]), wherein the modified red mud is substantially free from Na.sub.2O and/or glass. A novel material is thus provided, and the production thereof for use as a storage medium in a sensitive energy storage system in the low-, medium- or high-temperature range is described.