R&D of low activated Fe-Mn-Cr high strength non-magnetic steel, (I) screening test for constituent optimization and fundamental characterization test

It is very important to develop low activated/non-magnetic materials as lar ge scale structural materials for fusion reactors. In the structural design of JT-60SU, low activated/non magnetic materials with high specific streng th and low decay heat characterizations are required. In the present paper, a new low activated/non-magnetic material(15.5 Mn-16C r-0.2 N 0.3 Si-0.2C(wt%)) based on the conventional high manganese steel wi th lower Ni, Co, C, N and Mn contents fur the purpose of lower activation a nd decay heat was developed and the mass production conditions of the mater ial were optimized. Fundamental material characterization tests of the new material developed i n present study were carried out, and the following conclusions are derived : (1) Lower activation characterizations with the new materials in the order of 1/10 of that of SUS316L steel (2) Higher strength of the material in the order of 2 similar to 3 of SUS31 6L steel (3) Lower decay heat with higher thermal conductivity with comparison of SU S316L steel.