Year
2010
Abstract
This paper covers the history, current situation and expected future of criticality safety in transport. The bases for the current requirements must be easily available to avoid future misunderstandings. Since the first 1961 edition of the IAEA Transport Regulations there have been misunderstandings, often due to the combination of radiological and criticality safety. The definitions of a fissile material and of a confinement system are examples of recent confusion. Any radioactive material with trace quantities of fissile nuclides has also been a fissile material. This will change. Natural and depleted uranium that is not in the same package as other fissile material will remain excluded. The concept of a material design remains controversial, even though it is used in current Regulations and keeps millions of professional material designers busy. The confinement system is a misunderstanding. A small problem was ‘solved’ by a definition that is completely different to the intent. The evidence is now clear; the confinement system varies from nothing to five page descriptions. It is a safety problem since the confinement system is defined to be all that is needed to preserve criticality safety. Specialists agree that the confinement system has totally lost its original intent: subcriticality of the containment system if it could be removed from the main packaging. This is related to loading, unloading, inspection and emergency response. A constructive cooperation between criticality safety and other specialists between January 2008 and January 2010 appears likely to result in improvements concerning safety and usefulness of the Regulations. Other conference papers are expected to present the improvements in more detail.