CLEARANCE/EXEMPTION LEVELS FOR SLIGHTLY RADIOACTIVE MATERIALS ARISING FROM NUCLEAR DECOMMISSIONING AND NON-NUCLEAR INDUSTRIES

摘要

The management of the relatively large volumes of slightly radioactively contaminated material, arising from the decommissioning of nuclear facilities, represents a substantial fraction of the cost of such projects. The recycling of a relevant fraction of this material (or its reuse or disposal) without radiological restrictions, was identified by a Task Group of the OECD/NEA Co-operative Programme on Decommissioning, as a significant means of reducing such costs. The lack of internationally accepted "clearance levels" of radioactivity, at which the material could be utilised without radiological restrictions, seriously limits recycling as a waste management option. The emergence of the NORM/TENORM issue is of great significance for the discussion of clearance regulations. TENORM arisings occur in huge quantities, two to three orders of magnitude larger than those used in European studies on recycling in the nuclear industry, and the activity levels are generally the same as in very low to low-level nuclear waste. The regulation of TENORM is in its early stages. Their occurrence in a large number of industries, as well as their activity levels and quantities, has not been generally appreciated, even by regulatory authorities, until fairly recently. National and international bodies have suggested or are in the process of suggesting regulations for TENORM. The most important development is the publication of the European Commission Directive of May 1996 (ratified in May 2000) laying down basic safety standards for protection against ionising radiation, arising both in the nuclear and non-nuclear industries. The International Atomic Energy Agency has also started looking into this area in connection with the revision of its Safety Series 89 document. Significant to note is that both these bodies suggest release criteria into the general economy that are more relaxed for the radioactive materials from non-nuclear industries than for similarly contaminated material from nuclear industries. This issue is being taken up by several other bodies as well. This paper reviews the current debate and underlines the need for consistency in developing regulations and criteria for exemption and clearance of all radioactive materials regardless of their origin.