Analysis and Measurement of Loss of Radioactive Contents of a Type-B(U) Package Design for Transport of Cobalt 60

The International Atomic Energy Agency's Regulations for the Safe Transport of Radioactive Material (IAEA 1990a) rule the international transport of such material and provide the basis for domestic transport regulations in Argentina. The document establishes the technical, operational, and administrative requirements which shall be accomplished to carry out the transport of radioactive material (RAM). In order to achieve an appropriate level of safety during transport, the Regulations, inter alia, specify shielding and containment performance requirements for each type of package. This paper considers compliance assurance with the maximum level of loss of radioactive contents (LRC) established by the Regulations for a Type B(U) package design used for the transport of 12.95 PBq of 6 °Co, as a special form radioactive material. In particular, paragraph 548 of the Regulations establishes the following acceptance criteria when the package is subjected to the tests to withstand: normal conditions of transport, the LRC is restricted to :5; 10-6 A2/hour, and (1) accident conditions of transport, the LRC is restricted to~ A2/week for 6 °Co. (2) According to the Regulations, the structural and thermal performance of the special form RAM is high enough to ensure containment under both normal and accident conditions in transport. However, due to the very high specific activities of 6 °Co involved (about a maximum of8 TBq.g-1 from a CANDU Type Reactor in Argentina), if a few milligrams of 60Co in the form of aerosolized material were released from the containment system into the environment, this would imply an important LRC with its associated risk. Taking into account the above concepts, the authors of this paper have assumed that the evaluations of package design compliance for leakage testing are primarily based on assuming both the failure of a special form RAM during the transport of packages and the possibility of noncompliance, during their manufacture, with the acceptance criteria specified in the leaching and volumetric leakage assessment methods. For such purpose, different scenarios were considered so as to verify package containment compliance with the Regulations' requirements.