In order to produce a high magnetic field, a central solenoid (CS) model coil was constructed at Japan Atomic Energy Research Institute (JAERI) under international collaboration on the International Thermonuclear Experimental Reactor (ITER) project. For the jacket material of the CS model coil, INCOLOY908 alloy was used. The material has susceptibility to the Stress Accelerated Grain Boundary Oxidation (SAGBO) cracking under the conditions of certain tensile residual stress, oxygen concentration and heat treatment temperature. It is recommended that the tensile residual stress of the jacket material should be below 200 MPa during heat treatment in the fabrication processes. In this study, two kinds of vacant jacket samples, straight and bent, were used in order to investigate the induced stress during the coiling process. The spatial distributions of the lattice strain and the elastic constants of INCOLOY908 were measured non-destructively to evaluate the residual stress using the neutron diffractometer for the residual stress analysis (RESA) installed at the research reactor JRR-3M of JAERI. The FEM simulation showed good agreement with the results of the internal residual stresses by the neutron diffraction measurements qualitatively.
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