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

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