Mechanical tensile test of the full-size ITER TF conductor jacket materials at 4.2 K

• We conduct the tensile test of the full-size TF conductor jacket at 4.2 K.
• The fracture of the jacket at 4.2 K is a combination of ductile and brittle.
• The TF conductor jacket satisfied the ITER requirements of the mechanical properties.
• The result of full-size tube at 4.2 K is more representative and important.

316LN stainless steel is selected as a material for toroidal-field (TF) conductor jacket of International Thermonuclear Experimental Reactor (ITER). In order to evaluate the true mechanical performance of the jacket material at 4.2 K and its suitability as the ITER TF conductor jacket, the mechanical properties of the full-size TF conductor jacket tube and sub-size specimens at 4.2 K and 300 K were investigated according to ASTM standards. The measured yield strength and elongation at 4.2 K for sub-size specimens and full-size tubes are more than 950 MPa and 20%, respectively. In addition, the fractographies of all fractured specimens were observed using scanning electron microscope (SEM). These results suggest that the TF conductor jacket can satisfy ITER requirements and the result of the full-size tube at 4.2 K is more representative and important for practical applications.