Regulation of the core coolant flow rate of a natural circulation reactor

Abstract

A natural circulation reactor, especially a boiling water reactor, includes a reactor pressure vessel, a reactor core and a core jacket disposed within the reactor pressure vessel, surrounding the reactor core and having at least one inlet port and one outlet port for core coolant. A flow path for the core coolant, which is formed between the core jacket and the reactor pressure vessel, leads through the inlet port into the core jacket and has a flow cross section. At least one throttle element is disposed in the flow path for varying the flow cross section in order to regulate the core coolant flow rate. The flow cross section can be both increased and reduced in size by varying the cross sectional area of the throttle element, so that a regulation of the power of the natural circulation reactor is carried out in a simple way and, in an incident, a reduction in power to approximately 40% of the instantaneous reactor power is ensured. A method is also provided for regulating the core coolant flow rate through a reactor core of a natural circulation reactor.