DRAFT OF AN INTERNATIONAL STANDARD FOR LEAKAGE TESTING ON PACKAGES FOR THE SAFE TRANSPORT OF RADIOACTIVE MATERIALS

The recommendations expressed by the International Atomic Energy Agency (IAEA) for the Safe Transport of Radioactive Materials lay down, among other things, the limits for the release of radioactivity by the packages which transport radioactive materials, in terms of activity per unit of time, under both normal and accident conditions of transport. However, no advice is given on the methodology to be followed to demonstrate that the specified criteria have been met. The choice of methodology is left to the package designer, but the methodology must be agreed by the Competent Authority during the process of package approval. In most cases it is impossible to demonstrate by direct measurement that activity release limits are not exceeded. The method which is usually used to prove that a package has adequate containment is based upon carrying out a gas leakage test. In order to harmonise the approach of this problem worldwide, the INTERNATIONAL STANDARD ORGANIZATION (ISO) in 1986 asked a group of experts, representing about 15 countries, to write a standard concerning the leakage testing of packages for the safe transport of radioactive materials. This gave birth to the Working Group no1 0 rtVG 1 0) of the Sub Committee 5 \"Nuclear Fuel Technology• (SC 5) whose activities are overviewed by Technical Committee 85 \"Nuclear Energy\" (TC 85). The work of the WG 1 0 focused on the development of procedures to determine appropriate gas leakage rates and procedures for carrying out leaktightness tests. Such procedures are currently used but are often applied differently. The work was carried out with particular concern to provide for the future users of the standard (ie package designers, shippers of radioactive materials and Competent Authorities), a reference document which is accepted and used by the largest possible number of countries and provides the maximum help to all concerned.