Simulator training in accident management. First experiences in Germany

In German nuclear power plants emergency measures for severe accidents have been developed. Some of these require actions by the shift within a few hours. Due to the great complexity and the expected stress. It is necessary to train shift personnel on a simulator. One of these scenarios is the complete loss of all feedwater supply. When the steam generators are empty, secondary side measures have to be done with highest priority in order to prevent the primary side from heating up. Secondary side measures are the depressurization with the following feeding of the empty steam generators using the pressurized feedwater tank or a mobile pump. The simulator has been set up for this feature and a first experimental training took place. The shift had no problems with the secondary side measures when using the emergency manual. On the contrary several measures taken by the shift delayed the evaporation of the steam generators for 3100 s in comparison to the anticipated evolution. That is a result of the great experience of the shift. Emergency training for severe accidents on the PWR III-simulator delivers useful experiences and knowledge for various fields: realistic shift task assignment, improvement of the emergency behaviour due to the shift's experiences, testing the emergency manual and testing of alarm phases should be mentioned. (orig.) (12 figs.)