Long term management of graphite waste in France - 13106

Industrial long-term management solutions are available in France (repositories) for low and intermediate level short-lived waste (LIL-SL waste) and very low-level waste (VLL waste). These existing solutions are briefly described below. The management strategy for the other categories of radioactive waste is defined in the 2006 Planning Act on the sustainable management of radioactive materials and waste (Act 2006-739 of 28 June 2006). For high level (HLW) and intermediate level long-lived (IL-LLW) waste, reversible disposal in a deep geological repository is studied, with license application planned to be issued in 2015, and, subject to authorization, the repository would be commissioned in 2025. The relating R and D program is carried out within the Meuse / Haute-Marne Underground research laboratory. For low level long-lived waste Andra provided the Government by the end of 2012 with a report outlining various potential management scenarios. The description of these scenarios for graphite waste constitutes the main topic of this article. Since 2010 recent developments in graphite waste treatment and progress in radiological characterization led Andra and waste owners to consider alternative management scenarios for these waste, based on potential treatment and sorting, making it possible to open different disposal options. The following scenarios are being investigated from the perspectives of safety, cost and project risks: - Separate management of graphite sleeves and piles as a function of their radiological inventory. In this scenario, piles would be co-disposed with radium bearing waste in a shallow disposal facility while remaining graphite waste, including sleeves, would be disposed with IL-LL waste in Cigeo; - Extraction of radionuclides, co-disposal of partially decontaminated graphite with radium bearing waste in shallow disposal facility and disposal of concentrated residues with ILW-LLW waste in Cigeo; - Gasification of graphite after decontamination, disposal of residues with ILW-LLW waste in Cigeo. - Design of a specific repository for the entire graphite waste or the consideration of its disposal of in Cigeo. The acceptability of piles in a shallow surface repository depends in particular on the inventory of Chlorine-36 and Carbon-14, on the leaching rate of Chlorine-36 and on the fraction of organic Carbon-14, on the inventory of Americium 241, Plutonium-239 and 241 and on Niobium-94 as well as on site characteristics. For the potential disposal of sleeves in Cigeo, a suitable packaging with respect to Cigeo requirements has to be defined. The sequences of their delivery have to be analysed in connection with their interim storage possibility. Finally the concerned graphite waste will be taken into account in Cigeo's safety case. For the 'decontamination' scenario, the decontaminated graphite disposal of in a shallow surface repository will also depend on the site characteristics, on residual radiological activities in particular in chlorine-36 and carbon-14 (organic and inorganic) and on their leach rate after treatment. These last two elements are connected to the accessible performance of treatment processes. The scenario 'gasification' with disposal of concentrated residues in Cigeo would lead to a significant reduction of the total volume to dispose of. The management of effluents and rejections on the processing plant site is to be examined.