14C selective extraction from French graphite nuclear waste by CO2 gasification

International audienceThe decommissioning of French gas-cooled nuclear reactors, all stopped since 1994, will generate 23,000 tons of nuclear waste containing 14C among other radionuclides. This work aims at presenting and testing a selective extraction treatment of this radionuclide from graphite waste by carbon dioxide gasification.In previous works, we highlighted that graphite turns into a heterogeneously degraded carbon with neutron irradiation and 14C could preferentially be concentrated in the most degraded zones. Moreover, these last react selectively with CO2 that would allow the 14C extraction from graphite waste.The results on graphite waste are promising with the quarter of 14C inventory extracted for a relative weight loss of few percent. Up to 68% of 14C inventory was extracted, but with a more important mass consumption. Thus, the potential of this selective 14C extraction would allow imagining alternative scenarios for graphite waste management