(FT/1-2) The IFMIF/EVEDA Project: Outcome of the First Engineering Studies

Pascal Garin1), Masayoshi Sugimoto2)
1) CEA, Rokkasho, France
2) JAEA, Rokkasho, Japan

Abstract.  IFMIF is an accelerator driven neutron source consisting of two deuteron accelerators bringing two intense beams carrying each of them 125 mA to an energy of 40 MeV. These beams interact with a 25 mm-thick liquid lithium flow circulating at a speed of nominally 15 m/s and generate an intense flux of neutrons whose energy is centered at 14 MeV, the energy of D-T fusion reactions. The accelerator main subsystems are the following: (i) The injector, creating the deuteron beam by means of electron cyclotron resonance and at an energy of 100 keV; (ii) The RadioFrequency Quadrupole (RFQ), bunching and accelerating the beam up to 5 MeV; (iii) The Matching Section, optimizing the beam before its entrance into (iv) The Drift Tube Linac, with a Half Wave Resonator superconducting structure, being currently assessed (the first section up to an energy of 9 MeV will be tested during EVEDA); (v) The High Energy Beam Transport Line, transporting and shaping the beam to its required characteristics at the entrance of the Lithium Target (a rectangle of 20×5 cm2 with a flat energy profile of 40 MeV). (vi) Diagnostics and auxiliaries complete the system. The rapid flow of lithium and the highly activated environment pose many challenging issues: (i) Hydrodynamics of the flow (a laminar flow is required with a maximum ripple of ±1 mm); (ii) Erosion and corrosion of the loop; (iii) Purification and monitoring of impurities (hydrogen, nitrogen, oxygen and carbon) at only a few ppm, because of the point above; (iv) Safety for the installation and the personnel; (v) Diagnostics implementation in a highly radioactive environment; (vi) Rapid change of the backplate, subject to neutrons flux up to 60 dpa per year. Finally, the Test Facilities, which will host the samples to be characterized, also raise severe issues: (i) Resistance to the intense flux of neutrons; (ii) Stable operating conditions for all samples (temperature, stress, neutron flux, etc.); (iii) Replacement and Remote Handling of all constituents; (iv) Cooling of the Test Cell. The main first activities were mainly centered on the preparatory work for the prototypes, with detailed thermal, thermo-mechanical, neutronics, etc. calculations and the first engineering work. First technological demonstrations were performed (RFQ brazing, backplate welding, erosion and corrosion measurements, etc.). The paper will review this work and present a synthesis of all activities conducted so far.

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