FUEL PRODUCTION Two installations designed and used to fabricate nuclear fuel are being decommissioned on the Tricastin site (Drôme département): one specialised in the conversion* of uranium (Comurhex), the other in the enrichment* of uranium by gaseous diffusion (Eurodif). The operating history of these old installations is not fully known; determining the pollution present in the soils beneath the structures therefore remains an important issue. Furthermore, the industrial processes used at the time involved large quantities of toxic chemical substances (uranium, chlorine trifluoride and hydrogen fluoride, for example): the containment of these chemical substances is also an issue, as are the risks related to internal contamination of the workers. SUPPORT INSTALLATIONS “Support installations” are certain installations intended for the storage and processing of radioactive effluents and waste. Most of them were commissioned in the 1960s and are located at Cadarache, Fontenay-aux-Roses, La Hague and Saint-Laurent-des-Eaux. These installations were not initially designed to allow the removal of their waste, and in some cases they were seen as being the definitive waste disposal site. Retrieval of the waste from these facilities is all the more complex and will span several decades. The decommissioning operations must take account of severe corrosion and soil pollution phenomena, caused by ageing of the installations and events which occurred during their operation. These difficulties are compounded by incomplete knowledge of the operating history and the state of the installation to be decommissioned. Of these installations, the UP2-400 plant, the first reprocessing plant for the fuel from the first generation reactors (GCRs) is being decommissioned. It contains highly irradiating waste, such as technological waste, rubble, earths and sludges, sometimes stored loose, without preliminary sorting. Decommissioning is thus carried out in parallel with WRC* operations, which require the implementation of complex, unique engineering processes. FUEL REPROCESSING AND WASTE MANAGEMENT This concerns the spent fuel and waste storage and reprocessing installations, located on the La Hague site and operated by Orano. Their decommissioning usually entails prior retrieval and conditioning of legacy nuclear waste (WRC*). Owing to the incomplete record of their history, the waste inventory and radiological status of these installation are hard to establish. The laboratories are faced with the problem of management of the waste stored on the site at a time when the storage or disposal solutions had not yet been put into place. LABORATORIES These installations, which date from the 1960s, were devoted to research, in order to support an emerging nuclear power industry. Four civil laboratories have so far been definitively shut down in France. Decommissioning challenges • 9
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