Transient analyses of the Jordanian 5 MW research reactor under LOEP accident

The Jordanian 5 MW research reactor is simulated to investigate its transient behavior under a Loss Of Electric Power (LOEP) accident. The reactor cooling system is under downward force convection during normal operation, and upward natural convection through flap valves during training and shutdown modes. A coupled neutron kinetics and thermal hydraulic model is used to analyze the behavior of the reactor under various conditions: (1) a wide range of open positions of flap valves, with valve opening pressures ranging from 0.5 to 3 kPa, (2) three pump coastdown flow rates of 100%, 50%, and 25% of the nominal value, and (3) number of flap valves: one and two. As a reference, the evaluation of the reactor parameters in the hot and average assembly is performed when the pressure difference across the flap valves is reduced to 1.5 kPa, as the design value. The flow inversion times in the hot and average assembly are analyzed for all of the cases. The second temperature peaks of coolant and fuel are presented in the analysis. This study discusses the differences among these cases. The general behavior of the reactor during LOEP is similar, but there are variations in important parameters such as flap valve open time, flow inversion time, and maximum fuel and coolant temperatures.