Serpentinite and ferroserpentinite concretes - shielding material of nuclear reactor biological protection

Long-term temperature tests (about 5000 hours) were effected for serpentinite concretes in the temperature range -30 degC to 450 degC. When heated to 200 degC the concretes were found to lose 75 to 90% of water content in dependence on the volume, geometrical shape and the age of concrete. At 300 to 350 degC after a sufficient time period, the water is completely lost. After 28 days of hardening, the serpentinite concrete showns a density of 2100 to 2200 kg.m-3 and a compression strength of 10 to 15 MPa. At 450 degC the density is about 2000 kg.m-3 and the compression strength increases 1.5 times. The thermal conductivity coefficients, shrinkage factors and linear expansion coefficients, the relaxation lengths of neutron flux and of gamma radiation are shown. The values are also given for ferroserpentinite concretes. The components are described of serpentinite and ferroserpentinite concretes and mortars. (H.S.)