Transportation Safety Aspects of Ore and Related Material – Inconsistencies in Current Exemption Values

The IAEA’s system for exemption of material from the transport regulations is based on the fundamental principle that exemption values should be commensurate with the risk posed by the material, as represented by effective dose and skin dose. Important departures from that principle as well as inconsistencies between exemption values for different radionuclides have resulted from special provisions for natural materials that depend on their intended use, and from exposure scenarios and other assumptions and rules used in the derivation of exemption values. This paper examines the sources and extent of inconsistencies in exemption values for transport, particularly as they relate to naturally occurring radionuclides, and suggests ways to achieve greater internal consistency in exemption values as well as greater consistency with the fundamental principle underlying the current system.