Investigations of 222Rn and 220Rn emanation rates from concrete and the influence of pressure and temperature on these parameters

Results of measurements of 222Rn and 220Rn emanation rates from light concrete and 222Rn emanation coefficient for this material are presented. The measurements were performed with the aid of an apparatus presented earlier. Cubes of light concrete were closed in an emanation chamber. Radon isotope concentrations in the chamber were measured for about two weeks since the chamber was closed. Emanation parameters were calculated using a suitable mathematical model. 222Rn and 220Rn emanation rates were respectively: 0.29 x 10-3 and 0.08 Bq·m-2·s-1. 222Rn emanation coefficient was 2.1%. The influence of temperature and pressure changes on 222Rn emanation rate was also measured. The investigated cubes were closed in the emanation chamber and then pressure in the chamber was decreased by about 75 mm Hg. After one hour 222Rn concentration in the chamber was 1.8 in relation to the concentration in the chamber in which was atmospheric pressure. While increasing pressure by about 65 mm Hg, relative 222Rn concentration was 0.29. (author)