14 C selective extraction from French graphite nuclear waste by CO 2 gasification

Abstract The decommissioning of French gas-cooled nuclear reactors, all stopped since 1994, will generate 23,000 tons of nuclear waste containing 14 C 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 14 C could preferentially be concentrated in the most degraded zones. Moreover, these last react selectively with CO 2 that would allow the 14 C extraction from graphite waste. The results on graphite waste are promising with the quarter of 14 C inventory extracted for a relative weight loss of few percent. Up to 68% of 14 C inventory was extracted, but with a more important mass consumption. Thus, the potential of this selective 14 C extraction would allow imagining alternative scenarios for graphite waste management.