Improved Design And Synthesized Appraisal Of Moderator System For TACR

With the great development of the world industry, to solve the energy shortage problem has gradually been put on the agenda by all countries in the world. Nuclear energy, which can be alternative to fossil fuels, as a clean, economic, large-scale energy, is gradually paid more and more attention to. However, the accidents of two nuclear power plants in the last century resulted in higher requirements on the safety aspects of nuclear power plants. The countries which have nuclear power plants, are working to improve the safety of reactor. One of the important ways is to develop passive safety of reactor. Canada, in accordance with its basic national conditions in the history is developing nuclear power technology of heavy water pressure tubular reactor (PHWR). Compared to the general PWR, CANDU reactor has significant differences on design. These characteristics also bring numerous advantages for the safety. The Atomic Energy of Canada Ltd (AECL) has cooperated with Tsinghua University to develop a new generation of thorium-based advanced CANDU reactor (TACR). This research work is a part of the project.In this thesis, a new concept with passive moderator system for TACR-1000 is presented, and is assessed by analyzing a loss of coolant flow acciden(tLOFA)using CATHENA Mod3.5d/Rev2, which is a thermal hydraulic computer code developed by AECL for CANDU.In this thesis, several types of reactor core residual heat removal system are described firstly, and then the problems of the original design of moderator residual heat removal system of TACR are analyzed. The moderator system and the coolant system are modeled by CATHENA code. Finally in a loss of coolant flow accident are simulated. By analyzing some important parameters after LOFA, such as the temperature, the pressure and the mass flow rate of the moderator system, the feasibility of passive safety of the moderator system design is proven, and the capability of core cooling by the moderator system is analyzed. It also focused on the analysis of the circular reserve water tank. The results show that in the loss of coolant flow accident condition, the system can remove the residual heat from the reactor core in time, and the design volume of the circular reserve water tank is enough.