Finite element analysis of the main reactor vessel in the China Initiative Accelerator Driven System

•The finite element analysis software ADINA is used to study the main reactor vessel in CiADS.•The maximum effective stress of all cases occurs at the weld of the cone and the cylinder on vessel.•The three areas bearing large stress are found and should be focused on in the subsequent engineering verification.•During the postulated ULOF accidents and UTOP accidents, the reactor vessel in CiADS will not experience plastic deformation. The China Initiative Accelerator Driven System (CiADS) was proposed by China Academy of Science since 2015. The reactor in CiADS is a subcritical fast neutron reactor cooled by a liquid lead–bismuth eutectic. The reactor operates at high temperature and bears high thermal stress. In addition to the heavy weight of the whole reactor, the vessel will bear large effective stress. If the effective stress exceeds the limit of the material, defects and cracks may occur on the main reactor vessel, which will affect the safety performances of the reactor. Therefore, it is very important to analyze the effective stress field of the reactor vessel. In this paper, the finite element analysis software ADINA was applied to analyze the reactor vessel in CiADS. We can preliminarily prove that the maximum effective stress that the vessel will bear during the postulated Unprotected Loss of Flow (ULOF) and Unprotected Transient over Power (UTOP) accidents is less than the yield strength of 316L stainless steel. Therefore, we can preliminarily conclude that the current material selection and structural design of the CiADS vessel could survive the postulated transient accidents considering the effective stress effect.