Containment in-situ post accident sampling and emission monitoring for design basis and severe accidents

In order to reduce the residual risk in case of severe accident the German Reactor Safety Commission imposed additional recommendations that provision are made for: Post Accident Sampling System (PASS ) for the confinement atmosphere for obtaining of information on the condition of the core and potential hazards to the environment; Emission monitoring for containment venting. In-situ PASS provides the following information: activity concentration of radioactive aerosols, gaseous iodine and noble gases and composition of gases present in the containment atmosphere (CO, CO2, O2 etc.).The emission monitoring system has the task of monitoring radioactive materials discharged during DBA or severe accident if filtered confinement venting will be performed. The data obtained from the monitoring serves as a base for the implementing of the emergency response actions. The system is designed for the maximum activity concentration at the time of early containment venting, commenced in the event of a core melt accident - 1011 Bq/m3 aerosol bound radionuclides; 5.1011 Bq/m3 gaseous iodine isotopes and 2.1015 Bq/m3 radioactive noble gases