Severe accident management measures for a generic German PWR. Part I: Station blackout

This paper focuses on analysis of severe accident management measures for a generic German PWR of type Konvoi. A nuclear power plant model based on the severe accident code ATHLET-CD was developed in order to assess the code applicability for simulation of accident scenarios with core degradation. It was applied for investigation of two main groups of accident scenarios: station blackout and small-break lossof-coolant accident.

Part I of series of two papers analyses the plant response in case of hypothetical station blackout severe accident. Assessment of accident management measures in the preventive and in the mitigative domain is performed, where a focus is given on the combination of primary pressure reduction and injection by portable equipment directly into the reactor circuit. Key timings for operator actions are deduced. Both positive and negative effects of the investigated accident management measures are discussed. The results from the station blackout simulations showed that the time until core degradation can be delayed by application of primary side depressurization and usage of mobile pump as accident management measures. Depending on the time of injection significant reduction of the hydrogen and fission products releases can be obtained. In case that early water injection is possible, severe core damage might be prevented.