Fusion Programme - ENEA - Fusione

Fusion Programme1×10 -6Tensile creepIndentation creepFig. 3.40 - Converted indentation creepdata and uniaxial creep dataCreep rate (s -1 )1×10 -7220 230 240 250 260 270 2801×10 -8 Stress (MPa)3.8 International FusionMaterial Irradiation FacilityThe activities carried out during 2007 in theframework of the Broader Approach/International Fusion Materials IrradiationFactility (IFMIF) Engineering Validation and Engineering Design Activities (EVEDA) phase were mainlydevoted to implementing the target design, particularly in the version of the “bayonet concept”, proposedby ENEA (fig. 3.41). The main topics were thermohydraulic investigation, materials-compatibility study inthe presence of high-velocity flowing Li and optimisation of remote handling procedures.The first step for the engineering design of the European version of the IFMIF target is theEngineering thermohydraulic profile. Several calculations and experiments have shown that thedesign of the transition from the straight to the curved profile is accompanied by significant flowEU target instabilities which cannot assure a stationary flow regime. In this condition a prematurerupture of the back-plate could be expected as well as insufficient neutron production. Toprevent this type of flow instability, ENEA studied two alternative profiles: parabolic and linearly variableradius. The proposal based on a parabolic profile is illustrated in figure 3.42 where it is compared with thepresent profile based on a straight line connected to a constant radius curvature. The difference between0.20H(m)0.150.10StraightConstantradius0.0500Parabolic0.01 0.02 0.03 0.04 0.05 0.06L(m)2007 Progress ReportFig. 3.41 - Target assembly (bayonet concept)Fig. 3.42 – Back-plate parabolic profile64