High-Temperature Reactor Module Power Plant: Safety Analysis Report: Event Flows. Chapter 6.2

Automatic translation: With the HTR module, the following events lead to an unwanted temporal increase in the reactivity of the core and the reactor power: - Incorrect extension of reflector rods or small ball cut-off elements - Intrusion of moderating substances into the core (water) - Incorrect start-up of the primary coolant throughput (over the negative temperature coefficient of reactivity) - Incorrect lowering of the cold gas temperature (above the negative temperature coefficient of reactivity) - Densification of the fuel assembly during an earthquake. Furthermore, reactivity accidents are due to the unintentional Introducing turn-off reactivity into the core.