Transport of Low-Level NORM – A Case for Consistency and Practicality

In 1996 the IAEA adopted a system for exemption of low-level radioactive material from transport regulations based on the principle that exemption values should be commensurate with the risk posed by the material as represented by the maximum potential radiation dose to individuals. For many naturally occurring radionuclides the derived dose-based, radionuclide-specific exemption concentrations were substantially lower than the previous radionuclide-independent definition of radioactive material (70 Bq g-1) due to the stringent dose criterion applied. It was recognized that this would bring large quantities of previously unregulated naturally occurring radioactive material (NORM) handled in industry into the scope of the transport regulations. To minimize the economic impact of the dose-based values, a special provision was included to provide for a 10-fold increase in exemption values for radionuclides in natural material provided the material is not intended to be, and has not previously been, processed for recovery of its radionuclides (the wording regarding previous use was added in 2003). This “10 times” or “10x” provision for certain natural material reflects a second concept underlying IAEA guidance, namely, that a dose criterion may be relaxed within cautious bounds to achieve a balance between practical issues and radiological concerns. On the other hand, restriction of the provision on the basis of past or intended use of the material is inconsistent with the basic principle underlying the Transport Regulations in that there is no risk basis for assigning different exemption values to identical materials on the basis of their past or anticipated use. In fact, under this provision the same material can move in and out of the scope of regulatory control as its anticipated use changes. As a practical matter, safety guidelines for potentially hazardous material should be based on measurable properties of the material and not on intended use. To improve the practicality as well as the consistency of the Transport Regulations as applied to NORM, the 10x provision should be revised to apply to all natural materials, regardless of their intended use.