tailieunhanh - THERMAL-HYDRAULIC IN NUCLEAR REACTOR

I. Introduction An important aspect of nuclear reactor core analysis involves the determination of the optimal coolant flow distribution and pressure drop across the reactor core. On the one hand, higher coolant flow rates will lead to better heat transfer coefficients and higher Critical Heat Flux (CHF) limits. On the other hand, higher flows rates will also in large pressure drops across the reactor core, hence larger required pumping powers and larger dynamic loads on the core components. Thus, the role of the hydrodynamic and thermal-hydraulic analysis is to find proper operating conditions that assure both safe and economical operation of. | THERMAL-HYDRAULIC IN NUCLEAR REACTOR GS. Trần Đại Phúc THERMAL-HYDRAULIC IN NUCLEAR REACTOR Summary Introduction Energy from fission Fission yield Decay heat Spatial distribution of heat sources Coolant flow & heat transfer in fuel rod assembly Enthalpy distribution in heated channel Temperature distribution in channel in single phase Heat conduction in fuel assembly Axial temperature distribution in fuel rod Void fraction in fuel rod channel Heat transfer to coolant THERMAL-HYDRAULIC IN NUCLEAR REACTOR I. Introduction An important aspect of nuclear reactor core analysis involves the determination of the optimal coolant flow distribution and pressure drop across the reactor core. On the one hand, higher coolant flow rates will lead to better heat transfer coefficients and higher Critical Heat Flux (CHF) limits. On the other hand, higher flows rates will also in large pressure drops across the reactor core, hence larger required pumping powers and larger dynamic loads on the core . | THERMAL-HYDRAULIC IN NUCLEAR REACTOR GS. Trần Đại Phúc THERMAL-HYDRAULIC IN NUCLEAR REACTOR Summary Introduction Energy from fission Fission yield Decay heat Spatial distribution of heat sources Coolant flow & heat transfer in fuel rod assembly Enthalpy distribution in heated channel Temperature distribution in channel in single phase Heat conduction in fuel assembly Axial temperature distribution in fuel rod Void fraction in fuel rod channel Heat transfer to coolant THERMAL-HYDRAULIC IN NUCLEAR REACTOR I. Introduction An important aspect of nuclear reactor core analysis involves the determination of the optimal coolant flow distribution and pressure drop across the reactor core. On the one hand, higher coolant flow rates will lead to better heat transfer coefficients and higher Critical Heat Flux (CHF) limits. On the other hand, higher flows rates will also in large pressure drops across the reactor core, hence larger required pumping powers and larger dynamic loads on the core components. Thus, the role of the hydrodynamic and thermal-hydraulic analysis is to find proper operating conditions that assure both safe and economical operation of the nuclear power plant. THERMAL-HYDRAULIC IN NUCLEAR REACTOR This chapter presents methods to determine the distribution of heat sources and temperatures in various components of nuclear reactor. In safety analyses of nuclear power plants the amount of heat generated in the reactor core must be known in order to be able to calculate the temperature distributions and thus, to determine the safety margins. Such analyses have to be performed for all imaginable conditions, including operation conditions, reactor startup and shutdown, as well as for removal of the decay heat after reactor shutdown. The first section presents the methods to predict the heat sources in nuclear reactors at various conditions. The following sections discuss the prediction of such parameters as coolant enthalpy, fuel element temperature, void fraction,