Creys-Malville (Superphenix) decommissioning program and sodium treatment

The Creys-Malville or Superphenix NPP is a 3000 MWth sodium-cooled Fast Breeder Reactor, with four secondary sodium loops and 2 x 620 MWe turbogenerators. Superphenix is a pool-type reactor, with 3,300 tons of primary sodium and 2,500 tons of secondary and auxiliary sodium. The Fast Reactor design requires the use of a non-moderator coolant, which explains why water is de facto eliminated. Most of the Fast Reactor designs worldwide, and that includes Superphenix, use sodium as coolant, based on the following criteria: - non moderator, - small neutron capture cross section, - high power density removal capacity, - easy pumping, - large operating range in the liquid state without pressurization, - good radiation behaviour, - limited piping corrosion, - limited noxiousness, - high industrial availability and low cost. Superphenix is the largest Fast Reactor in the world. It reached first criticality in September 1985 and first grid connection in January 1986. Following a French governmental decision to abandon the FBR technology, Superphenix was officially shutdown in February 1998. The decommissioning of Creys-Malville is part of the EDF industrial strategy, which aims at dismantling its 8 'first-generation' reactor units and Superphenix, over a 25-year period. To this end, EDF has established a specific unit dedicated to the decommissioning of nuclear power plants, waste management and environment protection: the Engineering Center for Decommissioning and Environment (CIDEN, Lyon). The Creys-Malville site is part of the CIDEN organization. The aim of the Creys-Malville decommissioning project is to achieve the complete dismantling of the plant by 2026. The regulatory frame is now fully set (statutory decrees of March 2006) and allows the dismantling of the reactor and all decommissioning-related operations until the end. (author)