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Conference Article: The uncertain future for nuclear graphite disposal: Crisis or opportunity?

Abstract

Over the last twenty years, numerous proposals have been made for the long-term treatment of radioactive graphite waste. These plans have ranged from sea dumping through incineration to land-based disposal, sometimes preceded by a variable period of “safe-storage” within the original reactor containment, to allow for the decay of shorter-lived isotopes ahead of dismantling. A number of novel chemical or physical pre-treatments of the graphite, with the objective of facilitating its subsequent disposal or improving the environmental consequences of the chosen disposal route, have also been suggested. There are patents issued on systems for transmutation of long-lived isotopes to reduce the radiological consequences of disposal of intact graphite, and for separation of certain isotopes such as carbon-14 from the matrix in an incineration process. Although these far-reaching proposals are not apparently cost-effective, scope for cost-recovery does exist, i.e ., in terms of disposal of the separated carbon-14 in cements used for immobilisation of other radioactive solid waste materials. More recently, political and environmental factors have further complicated the issue. Nuclear regulators are challenging the proposed length of “safe-storage” schemes on the basis that essential knowledge on the reactor materials may be lost in the interim. International agreements such as OSPAR have effectively eliminated the possibility for disposal at sea, whilst public opinion is strongly expressed against any expansion of existing land-based disposal sites or the creation of new ones. As a particular example, the United Kingdom authorities recently denied to the official body charged with the development of a deep repository the necessary planning consents to develop an exploratory rock-structure laboratory on the most favoured site. The current drive towards minimising or eliminating any radioactivity release to the environment has the unintended consequence of causing the waste to be retained in interim surface storage. It appears to the authors to be an appropriate time to review the situation closely and to consider the problem entirely on the basis of established scientific fact and a comparative risk analysis, unfettered by the perceived political constraints to which the nuclear operators and decommissioning organisations are necessarily subjected. This paper seeks to raise again for scientific debate all of these possibilities for graphite disposal, without prejudice necessarily to political constraints, in order to try to focus on genuinely the most satisfactory outcome to all concerned.

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Reference:

IAEA Technical Committee Meeting on "Nuclear Graphite Waste Management", held from 18-20 October 1999 in Manchester, United Kingdom

International Atomic Energy Agency, Vienna (Austria)

TCM-Manchester99, pp:13-28