Publication

Abstract : Earthquakes, low-probability high-risk events which brings out the deficiency in the design and construction of components and buildings. Many seismic design codes given by various standards aims to reduce the damage during earthquake or to avoid serious accidents. In case of a Nuclear Power Plant, all safety related structures, systems and components are designed to with stand a very low probability of earthquake. This work gives the details of seismic analysis by Time history method for a typical Steam Generator (SG) used in sodium cooled fast breeder reactor. Steam generator of a sodium cooled reactor have sodium in shell side and water in tube side unlike water cooled nuclear reactors, where tube side and shell side is water. The failure of tubes in sodium cooled fast reactor steam generator result in leaking of sodium to water side causing sodium water reaction which is explosive in nature. The large energy release in sodium water reaction will damage the complete structure of SG and connected equipments causing shutdown of the plant. Hence it is very important to ensure the safety of the SG at all operating conditions even during event of severe earthquake. In this work the structural integrity of SG is analysed for events of earthquakes viz. Operating Basis Earthquake (OBE) and Safe Shutdown Earthquake (SSE) by performing seismic analysis by Time history method. The stresses at various critical locations are estimated and checked against limits given by ASME Section –III NC rules