Transient analysis of the primary system of a liquid metal-cooled fast breeder reactor plant

A computer-aided simulation is developed to analyze the transient behavior of the primary system of liquid-metal-cooled fast-breeder-reactor (LM GAMMA BR) plants of the loop type. A set of nuclear, thermal, hydraulic, and control models for the primary system is developed to simulate the transient response of sodium cooled fast breeder reactors for normal operating conditions, for a class of postulated accidents which do not disturb the system geometry, and for a major pipe rupture accident. The analytical submodels of the primary system components and systems are assembled into five major models which are coded in the FORTRAN IV language to form five computer codes. These major models simulate: (a) the dynamics of sodium flows in the primary system governed by forced and natural circulation effects and the operation of the primary pumps and primary flow/speed control system, (b) reactor heat-transfer, (c) neutron kinetics, reactivity feedbacks, and reactor power control, (d) intermediate heat exchanger heat-transfer, and (e) sodium transport in the primary piping system. The primary system code is used to analyze five representative transients: (a) ramp change of power level, (b) single pump coastdown, (c) reactor scram shutdown, (d) coastdown of all primary pumps, and (e) loss of coolant accident. The code can be used to analyze other transients as well, of similar or of different types, using appropriate sets of input data or by making minor modifications which can be easily accommodated