ASN Report 2018

1.4  ̶  Radioactive waste management support facilities • Treatment Treatment is a fundamental step in the radioactive waste management process. This operation serves firstly to separate the waste into different categories to facilitate its subsequent management, and secondly to significantly reduce the volume of waste. The La Hague plants which process the spent fuel assemblies are involved in this process because they apply a dissolution and chemical treatment process to separate the cladding and the fission products. The hulls and end-pieces are then compacted to reduce their disposal footprint. Socodei’s melting and incineration facility called “Centraco” significantly reduces the volume of the VLL and LL/ILW-SL waste that is treated there. This plant has a unit dedicated to the incineration of combustible waste, and a melting unit in which the metal waste is melted down. The radioactive effluents can also be concentrated by evaporation, like the operations carried out in Agate (BNI 171), with this same aim of volume reduction. • Conditioning Radioactive waste conditioning consists in placing the waste in a package which provides a first containment barrier preventing radioactive substances being dispersed in the environment. The techniques used depend on the physical-chemical characteristic of the waste and their typology, which explains the large variety of packages used. These packages are subject to approvals by Andra if they are intended for in-service disposal facilities, and to packaging agreements by ASN if they are intended to be directed towards disposal facilities still under study. In some cases the packaging operations are carried out directly on the site of waste production, but they can also take place in dedicated facilities, like the La Hague plants, which package spent fuel hulls and end-pieces in CSD-C packages and fission products in CSD-V packages, and the effluent treatment stations such as the Stella station in BNI 35. The waste conditioning operations are sometimes carried out in the facilities in which they are to be stored, which will be the case for the LL/ILW-SL waste packages in the Iceda facility, or directly in a disposal facility, such as Cires and CSA which carry out these operations on a portion of the incoming packages. • Storage Storage, as defined by Article L. 542-1-1 of the Environment Code, is a temporary management solution for radioactive waste. The waste is kept in storage for a limited period pending its transfer to disposal, or in order to achieve a sufficient level of radioactive decay to enable it to be sent to conventional waste management routes in the particular case of very short-lived waste, which comes chiefly from the medical sector. Some facilities (see opposite) are specifically dedicated to the storage of radioactive waste, such as Écrin, commissioned in 2018, and Cedra. This will also be the case with Iceda and Diadem once these facilities enter service. As for the CSD-C and CSD-V packages, they are stored directly in various facilities on the La Hague site pending commissioning of the deep geological repository for HL and ILW-LL waste. • Research and development Support facilities are used for research and development work to optimise radioactive waste management. Among these, the Chicade facility (BNI 156) operated by the CEA on the Cadarache site conducts research and development work in low-level and intermediate-level objects and waste. This work primarily concerns aqueous waste treatment processes, decontamination processes, solid waste packaging methods and the expert assessment and inspection of waste packages. 364  ASN report on the state of nuclear safety and radiation protection in France in 2018 14 – RADIOACTIVE WASTE AND CONTAMINATED SITES AND SOILS