Experimentelle Simulation eines Kühlmittelverlust-Störfalls mit dem AVR-Reaktor

One of the most severe accidents for a nuclear power plant is loss-of-coolant. To demonstrate inherent safety characteristics incorporated into small High-temperature Gas-Cooled Reactors, loss-of-coolant accident (LOCA) simulation tests have been conducted at the Pebble-bed High-Temperature Reactor Plant AVR. The planning, the licensing activities and pretests are described, and the conduct of the test and experimental results are presented. The LOCA test created conditions that would exist if a rapid LOCA occurred with the reactor operating at full power. The main LOCA test lasted for 5 days. After the test began, core temperatures increased for $\backsim$ 13 h and then gradually and continually decreased as the rate of heat dissipation from the core exceeded the simulated decay power. Throughout the test, temperatures remained below limiting values for the core and other reactor components. The maximum core temperature reached about 1080 °C. The main heat sink during the test was found to be the steam generator. Against expectations there seems to be a heat transport from the core to the steam generator by natural convection even at 1 bar Helium pressure