Setting radon-specific release criteria and demonstrating compliance for land affected by NORM

Residues from industrial activities involving naturally occurring radioactive materials (NORMs) may cause radiation exposures to members of the public, particularly when NORM-affected land is brought into residential use. To provide an adequate protection against radiation in such situations, the following limiting criteria are currently required in Spain for releasing NORM-affected land: (i) no more than a 300 μSv yr−1 increase (excluding radon doses) over the natural background; (ii) 222Rn concentrations in hypothetical future dwellings lower than 200 Bq m−3; and (iii) reduction of all radiation exposures to as low as reasonable achievable. This paper addresses some of the problems encountered in translating the 222Rn criterion into site-specific release limits and in demonstrating compliance with them.