Measured real-time data at a nuclear power plant and off-site dose assessment

In the case of the severe reactor accident two alternatives are available depending on accident phase: has the release already begun or is it only threatening. If the release has already started and the results measured by the environmental radiation monitoring system are available off-site doses and dose rates can be calculated based on actual releases but it can be expected that the calculated and measured external dose rate values are not identical. So the calculations should be corrected in a way or other to make additional re-runs consistent with the environmental measurements. Examinations are presented how to make use of the measured data in the NPP installation for off-site dose assessment, and for this purpose a concept for computerised tool is presented. (R.P.)