Simulating radiation levels

In this article one utilizes the MAAP4 (Modular Accident Analysis Package) computer code simulating the radiation levels caused by a severe accident in a nuclear power plant. It allows quick estimation of radiation dose rates and doses inside and outside the plant. It can help in risk assessment, equipment qualification analysis, emergency planning and training, emergency preparedness exercises, development of emergency operating procedures, and severe accident management. MAAP4 uses fission product releases determined by thermal-hydraulic code to calculate in-plant and ex-plant radiation levels. To accommodate realistic accident scenarios, release rates from the plant are allowed to vary with time. Because plume radiation doses are dramatically affected by plume height the MAAP4-DOSE uses a sophisticated first-principle approach to determine the rise of the high-momentum, high-temperature effluent jets that may result from containment rupture. (authors)