RADIOLOGICAL LIMITS FOR TYPE B PACKAGES WITHIN THE TERMS IAEA-SM-286/55 OF THE IAEA TRANSPORT REGULATIONS

The paper discusses the radiation levels and activity release limits applicable to Type B packages with particular reference to consignments of irradiated nuclear fuel. Within the IAEA Regulations for the Safe Transpon of Radioactive Material, external irradiation and maximum permissible non-fixed surface contamination levels are defined in terms of conventional radiological protection criteria, whereas permitted activity releases are expressed in terms of the non-special form Type A package contents limit A2 values and are not directly comparable. However, by considering a range of possible exposure scenarios relevant to the transpon of Type B packages and noting that an intake of A2 x 10-6 corresponds to an effective dose equivalent of 50 mSv, it is possible to derive the dosimetric limits implied by the permitted activity releases contained in the Regulations. This facilitates comparisons with external radiation and surface contamination limits under both normal transpon and accident conditions. ln the latter case, the safety standards for Type B packages implied within the Regulations may be compared with those widely used in the establishment of emergency guidelines at power reactor sites and other fixed nuclear installations.