I&HLW transportation and handling in a deep geological disposal

The reference solution for the long-term management of intermediate and high level long-lived radioactive waste in France is defined in the French law as deep geological disposal. IRSN is the technical safety organization whose responsibility is to assess the safety of the facility envisioned by the French radioactive waste management organization (WMO). IRSN bases its safety review on the safety case elaborated by the WMO, which is meant to evolve with the whole project development steps (conceptualization, siting, design, construction, operation and post-closure). With this regard, the demonstration of operational safety has to show evidence that, amongst other aspects, operations related to the transfer of the waste along ramp and drifts to its emplacement in disposal tunnels are safe.Among the scenarios to be taken into account when evaluating the safety of waste handling in underground tunnels, the occurrence of a fire is particularly scrutinized by IRSN, because of its potential impact on waste containment that could lead to radioactive material releases. Moreover, fires in tunnels have specific features, as underlined by experience feedback in conventional tunnels (underground subways, railways, roads...), that need to be taken into account in terms of duration of the fire, pressure effect, temperature, smoke dispersion, etc. In turn, a geological disposal facility shows important challenges when dealing with accidental situations such as a fire because of its architecture and size associated with a potentially tremendous radiological source term: evacuation, intervention, mitigation of consequences, etc.Therefore, waste transfer casks that will be designed specifically for underground handling in the geological disposal facility will have to withstand particularly severe accidental situations based on the occurrence of fire. The safety assessment related to these casks should at least embrace fire scenarios that are already scrutinized in transport of radioactive materials, especially in railway and road tunnels.