In the Gas-Cooled Fast Reactor (GFR) development plan, the Experimental Technology Demonstration Reactor (ETDR) is the first necessary step towards the electricity generating prototype GFR. It is a low power (∼ 50 MWth) Helium cooled fast reactor. The pre-conceptual design of the ETDR is shared between European partners through the GCFR Specifically Targeted Research Project (STREP) within the European Commission's 6th R&D Framework Program. After recalling the place of ETDR in the GFR development plan, the main reactor objectives, the role of the European partners in the different design and safety tasks, the paper will give an overview of the current design with recent progresses in various areas like:
○ Sub-assembly technology for the starting core (pin bundle with MOX fuel and stainless steel cladding).
○ The design of experimental advanced ceramic GFR fuel sub-assemblies included in several locations of the starting core.
○ Starting Core reactivity management studies model including experimental GFR sub-assemblies.
○ Neutron and radiation shielding calculations using a specific MCNP model. The model allows evaluation of the neutron doses for the vessel and internals and radiation doses for maintenance operations.
○ System design and safety considerations, with a reactor architecture largely influenced by the Decay Heat Removal strategy (DHR) for depressurized accidents.
The design of the reactor raises a number of issues in terms of fuel, neutronics, thermal-hydraulics codes qualification as well as critical components (blowers, IHX, thermal barriers) qualification. An overview of the R&D development on codes and technology qualification program is presented. Finally, the status of international collaborations and their perspectives for the ETDR are mentioned.