Radium content and radon exhalation rate from sulfur polymer composites (SPC) based on mineral fillers

Abstract

Several samples of materials of potential interest as component in building materials, especially in sulfur polymer concrete (SPC) composites, were checked for their radium content and radon exhalation rate. However, the radiation hazard strongly depends on radon exhalation rate from these materials, the influence of SPC composition was investigated concerning radon exhalation and emanation from the composite matrix. The accumulation method using RAD7 device was used for specific exhalation rate determinations. The activity concentrations of Ra-226 in the man-made tiles were in the range of 6.1–593 Bq·kg−1. The Rn-222 exhalation rates from these materials were in the range of 103 mBq·m−2 h−1–9.22 Bq·m−2 h−1, whereas from the SPC composites from 40.2 to 438 mBq·m−2 h−1. SPC manufacture technology and sulfur polymers applied for composites preparation allow for nearly 50-fold decrease of radon emanation coefficient. Different factors (e.g.: physical form of additives or polymer composition and its weight fraction) affecting radon emanation coefficient and its exhalation rate from examined raw materials and composites were discussed. Using a standard room parameters, the Rn-222 concentration resulting from its exhalation from the walls and annual internal doses were estimated indicating for satisfactory results even for raw materials of the highest Ra-226 concentration.