Research On Steady-state Operational Characteristic Of Integrated Pressurized Water Reactor

Around the safety and economy, the development of world's nuclear power faces towards two main aspects: improvement and innovation. The improvement means making use of the mature technology to incorporate into the current nuclear power plants, and the innovation means redesigning new "self-protection" type nuclear reactor which is based on inherent safety guaranteed by the laws of nature. Due to high safety, technical feasibility and economy, the innovatory Integrated Pressurized Water Reactor (IPWR) becomes the world's small and medium reactor research and development hot issues. In this paper, steady state operational characteristic is researched which aims at the IPWR.The physical calculation models such as reactor core, Casing Once-Through Steam Generator (COTSG), pressurizer and structure material, are established based on IPWR's main coolant system by means of the SCDAP/RELAP5/MOD3.4 code. The conservative methods and Best Estimate (BE) methods are used to calculate the steady state operational characteristic of main coolant system. The results can be listed as follows.The mass flow rate of natural circulation will increase and the flow will become more stable when the reactor power increases on the condition of the system with fixed construction. When the reactor power is more than 30%FP, the results from the conservative calculation are very close to those from BE calculation, and the relative error of the main thermal parameters is within±5%. Larger error exists between the two methods when the reactor power is less than 30%FP. Some thermal parameters, such as mass flow rate of natural circulation and thermal power will oscillate. Heat transfer characteristic of casing pipe is also analyzed. Mechanism analysis results show that the RELAP5/MOD3.4 code can be used to simulate the heat transfer process in COTSG, but it is necessary to ascertain resistance coefficients and heat transfer coefficients by means of experiments. Steady state operational characteristics are researched using the conservative methods. The trends of the thermal parameters are obtained and the temperature envelope curve of secondary fluid is ascertained.The present conclusions and methods can provide guidelines for the further studies on the IPWR.