Secondary SCRAM System for Liquid Metal Cooled Nuclear Reactors

Nuclear energy has the potential to provide large amounts of electricity reliably, with limited greenhouse gas emissions and without dependency on fossil fuels. However the sustainability of the nuclear reactors today is not optimal and can be further improved. This improvement is foreseen in the new generation of nuclear reactors, called Generation-IV reactors. Additionally these reactors are designed to be safer than currently existing reactors, by using innovative technologies. One important safety aspect is the ability to shut down the nuclear chain reaction. At least two completely independent systems have to provide a shutdown method for the reactor. These systems cannot have any common parts, and preferably should also operate using a different principle. One common way of shutting down the reactor is by inserting a neutron absorbing rod into the reactor core. This rod will then absorb a part of the neutrons in the reactor and stop the chain reaction. However in some, very unlikely, accidents it is possible that these rods cannot be inserted into the reactor, for instance due to deformation of the core. The purpose of this PhD was presenting an additional safety system, complementing the system based on the control rods. This system has to work in Generation-IV reactors, cooled with liquid metal.