Irradiation Effects in 2103/R3 Steel: Comparison Between Different Heats and Different Fabrication Procedures

The susceptibility to irradiation effects in different heats of the same steel and in parts of a reactor vessel that had gone through different stages in the manufacturing process was investigated. Fourteen sets of miniature impact specimens of Uddeholm UHB 2103/R3 steel, the pressure vessel material of the Ågesta reactor, were irradiated at 235 ± 15°C to a neutron fluence of 4 × 10¹⁸ − 10¹⁹ n/cm² (>1 MeV). The results indicate that there might be a difference by a factor of 2 in irradiation-induced transition temperature increases between materials from different parts of the vessel. Generally, changes in the hot-pressed material seemed to be larger. If irradiation-damage studies are performed on flat, normalized plate, the results are valid if an extra safety margin of 30°C is applied.