SOME ECONOMIC AND TECHNOLOGICAL QUESTIONS RELATED TO THE UTILIZATION OF CONCRETE IN THE SHIELDING OF NUCLEAR REACTORS (in German)
The basic requirements which must be met by concretes used for radiation- shielding applications are reviewed. High density, relatively high hydrogen content in the occluded water (0.4 to 1%), low heat of hydration, high specific heat capacity, high heat conductivity, a low value for the coefficient of thermal expansion and for the modulus of elasticity (resulting in a prevention of cracking and a minimization of the stresses produced by heating efects of the nuclear radiation), and a low value for the settling constant as well as high tensile strength (to prevent cracking) are prerequisites. The most widely used formulation for medium-weight concrete (bulk density on the density 3.5 tons/m/ sup 3/) is as follows: 60% barytes, 22% limonite, 11% portland cement, and 7% water; for heavy concrete (bulk density on the density 4.3 tons/m/sup 3.); 57% large and small steel scrap, 26% limonite, 13% portland cement, and 6% water. In order to increase the probability of neutron capture without emission of hard rays boron is sometimes added. The shape and particls size distribution of the heavy fillers are frequently unsatisfactory, resulting in low workability of the concrete mixtures, particularly when angular-shaped steel scrap is used as coarse aggregate. No effort should be made to reduce cement consumption since an increased cement content in the concrete results in high density of the latter, improves the workability, and increases the occluded water content. With slow- setting concretes, as is frequently the case when boron compounds are used, alumina cement should be used with the addition of calcium chloride. During the mixing of the concrete a pronounced tendency of the cement montar to stick to the walls of the mixer is observed and can be prevented by the addition of plasticizing compounds. When steel scrap is used the stratification of the concrete when it is poured into the mold and during the subsequent vibration must be prevented. Vibration is not required when friable aggregates such as barytes are used. (auth)
- Research Organization:
- Originating Research Org. not identified
- NSA Number:
- NSA-13-012007
- OSTI ID:
- 4262272
- Journal Information:
- Bauwirtschaft (West Germany), Vol. Vol: 11; Other Information: Orig. Receipt Date: 31-DEC-59; Related Information: Translated from Referat. Zhur. Khim. No. 9, 1958, Abstract No. 29642
- Country of Publication:
- Country unknown/Code not available
- Language:
- German
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Related Subjects
ALUMINUM OXIDES
BARIUM SULFATES
BARYTES
BORON
BORON COMPOUNDS
CALCIUM CHLORIDES
CAPTURE
CEMENTS
CONCRETES
DENSITY
DISTRIBUTION
ECONOMICS
ELASTICITY
EMISSION
EXPANSION
GAMMA RADIATION
GRAIN SIZE
HEATING
HYDROGEN
MIXING
NEUTRONS
PARTICLES
POLYMERS
RADIATIONS
REACTORS
SHIELDING
SPECIFIC HEAT
STEELS
STRESSES
TENSILE PROPERTIES
THERMAL CONDUCTIVITY
USES
VIBRATIONS
WATER