Survey on structural material investigations for SNR 300

Type 304 SS in a modified, fully austenitic version has been used for the construction of the primary and secondary heat transfer system, including the vessel and the pumps; the steam generators were built of 2.25 Cr-1 Mo-Nb ferritic steel. Coordinated programs involving INTERATOM, KfK, ECN, TNO, CEN/Mol have been performed. The SNR-300 project related structural material activities have provided a broad base to describe materials properties behaviour and design limitations under aspects of long-term component reliability and availability. High temperature design needs have been covered by the development of constitutive relations and computational programs. Integrity considerations and deformation limits under hypothetical circumstances have been verified successfully. Investigations on alternative materials for permanent structure have been started.