CEA are conducting a research programme (Viala and Salvatores, 1994) on the potential of thermal or fast reactors for transmutation of waste in partnership with EdF, FRAMATOME and COGEMA (Salvatores et al., 1997a). Different laboratories within CEA are working within the ISAAC programme on the physics of ADS including accelerator technology, the physics of source driven multiplying systems and spallation physics.

Feasibility work on accelerator structures with coupled cells and on beam dynamics has been carried out. Theoretical studies on high intensity accelerators have been carried out in support of experiments (FODO, on the beam dynamics) and (SATURNE, on the design of a 100 mA proton source) (IAEA-TECDOC-985, 1997a).

The physics of multiple sub-critical systems plays a central role and are being studied in several experimental programmes. The MUSE experiments (Salvatores et al., 1997b) in the MASURCA facility in CADARACHE are providing understanding on the neutron source and the impact of the source spectrum and environment at different levels of sub­criticality. Supporting experiments to determine actinide and fission product cross­sections are being carried out in the Geel LINAC, other experiments were also carried out in Superphenix.

On the spallation physics, thin and thick targets, spallation residual nuclei measurements, differential cross-sections’ measurements and neutron production rates

are being studied in the SATURNE experimental programme. Codes to model cascades include the code system SPARTE, supported by the Monte Carlo code TRIPOLI and the nuclide time evolution code DAEWIN. Future work envisages the coupling with the standard neutronics code ERANOS (Doriath et al., 1994).

System studies have been performed based on various scenarios, in which an ADS is used to develop a relatively clean source of nuclear energy within a fuel cycle, where LLFP are eliminated and radioactive wastes are concentrated in a small number of facilities in a nuclear reactor park.

Basic nuclear and particle physics is performed by the Institute National de Physique, et de Physique des Particles of CNRS, and also in the Direction Des Sciences de la Materie of CEA. The PRACEN research programme was set up in these laboratories to perform radiochemical studies within nuclear storage facilities. A recent joint research programme ‘GEDEON’, involving a collaboration between CNRS, EDF and CEA, has been set up to encompass the common areas of interest of the ISAAC and PRACEN programmes and to explore innovative options for waste management.