Abstract
The steam generator tube rupture (SGTR) of a nuclear power plant is a transient that is subject to numerous studies. The casing once-through steam generator has great heat-transfer capacity due to its dual-layer heat transfer structure. Base on the structure and operational characteristic of casing once-through steam generator used in small module reactor (SMR), a graphical model is designed using process module in APROS. Operating parameters of the casing once-through steam generator is simulated under steady state of different power load and SGTR condition. According to the results, the enthalpy and the temperature of secondary side outlet first increases and then decreases with the increasing power load and reaches the greatest value when the power load is 60%. Further study the impact of the position and degree of the breakage on the operating characteristics of the casing once-through steam generator when the steam generator tube rupture. The results show that the influence on the operation characteristic of the casing once-through steam generator increase when the tube rupture takes place in the position which is near the primary side inlet. And when the size of tube rupture becomes larger, the leakage mass flow from primary side to secondary side increase, thus cause the enthalpy and the temperature of secondary outlet further decrease. The simulating results fit theoretical analysis, showing that the casing once-through steam generator can be simulated accurately in APROS. Reference and guidance can be provided for the design and optimization of casing once-through steam generator as well as the safety analysis.
