Thermo-mechanical simulation for nozzle header of once-through steam generator by experiment and finite element method

The thermo-mechanical behaviour of the nozzle header of a steam generator developed for an integral reactor was investigated using experimental and finite element methods. The nozzle feedwater header suffers from severe thermal transient loadings during the operation of the nuclear reactor. The nozzle header is exposed to the low temperature inlet feedwater and the high temperature outlet superheated steam and the other side of the nozzle header contacts with the high temperature primary coolant. The temperature gradients result in high thermal stresses in the nozzle header. The thermal transient loading has been simulated in a test loop. The input and thermo-hydraulic parameters of the primary and the secondary system were. Strain gauges and thermocouples attached to the highly stressed region monitored the thermo-mechanical behaviour of the nozzle header. In parallel with the experimental study, the transient behaviour of the nozzle header was simulated by utilizing a commercial finite element code. The fluid temperature and pressure obtained from the test loop were used as inputs to the finite element analysis. As a result of this investigation, the thermo-mechanical load carrying capacity of the developed steam generator nozzle header was proved numerically and experimentally.