Concept for monitoring gaseous and aerosol-bound radioactive discharges from boiling and pressurized water reactor plants in the event of design basis and severe accidents

A new concept for monitoring radioactive discharge has been developed. The resulting system presented here is intended to meet the requirements set forth in the German Nuclear Safety Standard KTA 1503.2 (draft) for accident surveillance while at the same time being suitable for activity monitoring during containment venting. The system and typical modes of system operation are described for plants equipped with pressurized water reactors (PWRs) and plants equipped with boiling water reactors (BWRs). A combination of different methods of evaluation allows the space needed for instrumentation as well as the effort required for testing to be minimized.