The GEDEON program. An R and D initiative in support of the ADS development in France

The GEDEON initiative: R and D on basic physics issues of ADS. Also: R and D in the perspective of a 'demo' experiment. The context in France: R and D for waste management; R and D organisations have collaboration agreements with industrial partners; the French Ministry for Research has promoted a study on the relevance of an ADS 'demo'. The context in Europe: The 5th Framework Program; A tri-country initiative towards an 'ASAP demo' (at present being enlarged to other countries). GEDEON is coordinating and supporting R and D activities in this context. Four organisations are presently supporting financially GEDEON: CEA, CNRS, EdF, FRAMATOME. Workshop help to focus on issues and to start cooperative projects nuclear data, pyrochemistry, and materials for target and window. Also: some joint projects, such as the MUSE program at MASURCA. Links with ongoing R and D activities such as High Intensity Accelerators. Present R and D fields: Spallation Target physics: double differential data (analysis of SATURNE experiments), neutron multiplicities (GANIL), spallation product distribution (GSI). Nuclear Data Np-237 and Tc-99 σc in the resonance region (GEEL), Am-242 σf at thermal energy (ILL). Nuclear data validation with integral experiments: MA sample irradiation and Irradiated Fuel Analysis. Spallation physics and particle transport modeling: the SPARTE code. Neutronics and control of subcritical cores: the MUSE Program at MASURCA; MUSE-1, MUSE-2 (1995-96) with Cf-252 external source, MUSE-3 with commercial 14 eV n source. Future program: MASURCA cores coupling to a performing deuteron accelerator (GENEPI). System studies: scenario studies (e.g. double strata fuel cycle); use of thorium. Also reduced radiotoxicity 'at the origin'. Potential of pyrochemistry to handle highly active fuel and supports not compatible with PUREX (heterogeneous recycling targets, dedicated MA-based fuels); also: potential of the IFR concept revisited (homogeneous recycling). Potential of molten salts (e.g. to burn Pu and MA with a reduced TRU inventory, the AMSTER concept). Materials (case of Pb/Bi liquid target): behaviour of structural steels under proton and neutron mixed spectrum: at approx. 50-70 μA/cm2; approx. 100 pa in the window/50 pa in the target container; high H and He production (90 00 and 5 00 ppm respectively); potential embrittlement due to P, S (spallation products), etc. Corrosion and embrittlement due to Pb/Bi: a preliminary choice: 9 Cr martensitic steel. Program being built: between CEA and CNRS (irradiation effects, corrosion, embrittlement, technology for quality control); in the frame of the 5th Framework Program of EU. Need for full scale target irradiation (approx. 1 Wt). GEDEON supports activities towards that goal. R and D on high intensity accelerators. GEDEON has provided a link between the physicists developing ADS concepts and accelerator experts. Under the present collaboration between CEA and CNRS, a high intensity test-bed is being developed: IPHI, a 100 A 10 eV proton injector, which should make it possible to validate beam dynamics codes; knowledge of beam distribution; to demonstrate reliability-availability. Superconducting cavities should be used above 10000 eV. Measurements of conceptual single-cell unit are underway and prototyping of a multi-cell cavity is in progress. Major future undertakings: MUSE program; material studies and target development; irradiation effects: collaboration for experiments at PSI are presently under discussion; nuclear data: participation to the CERN TOF facility experiments; validation of the SPARTE code and its use for conceptual design. Safety of subcritical systems: physics, code development, experimental validation in MUSE. High intensity accelerators: specification and experimental tests of performances required by an ADS. System studies. Intercomparison with critical systems. Role of thorium