Exercise to protect against nuclear hazards at sea

Particularly in the event of a nuclear accident, international cooperation is vital – after all, radioactivity does not stop at national borders. In recent days, experts from 24 countries around the world have therefore carried out computer simulations of what would happen if an incident occurred on a nuclear-powered icebreaker in the Baltic Sea off the coast of Denmark.

Above all, the aim of the comparative calculations was to check the decision support systems for the forecasting and situational assessment of accidents involving the potential release of radioactivity into the environment. In particular, the aim was to determine whether the various participants would reach the same conclusions.

These comparative calculations, which were organised under the overall leadership of the Federal Office for Radiation Protection (BfS) and Karlsruhe Institute of Technology (KIT), took place from 17 to 24 November. A joint workshop was then held on 1 December to compare the results and to derive conclusions for international emergency preparedness.

BfS President Paulini: the importance of international cooperation

President of the Federal Office for Radiation Protection, Dr Inge Paulini

"The risk to nuclear power plants due to the war in Ukraine has further highlighted the importance of international cooperation with regard to radiological emergency preparedness," says BfS President Inge Paulini. "Even in the event of civilian incidents, coordination across borders can be decisive when it comes to protecting those affected."

The exercise was premised upon an accident in the Kattegat, around 40 kilometres east of the Danish city of Aarhus. The scenario was based on a fictitious accident affecting a nuclear-powered icebreaker, resulting in the release of a large quantity of radioactivity – on a scale that would mean health effects were likely for people in the surrounding area and measures were necessary to protect the population.

Participants in the exercise included representatives of 30 organisations from 24 countries around the world. They were tasked with determining what protective measures would be necessary using the RODOS computer-based decision support model. RODOS stands for "Realtime Online Decision Support System". The radioactivity calculations were based on the actual weather in the region, which is supplied to the BfS several times a day by the German Meteorological Service (DWD).

Overall, the participants rated the benefits of RODOS for situational assessment very positively. Nevertheless, there were some differences in the measures recommended to protect the population. Examining how deviations of this kind can be avoided in the future will be the subject of work over the coming months.

Basis for specific emergency preparedness measures

dispersion calculation

With the help of the RODOS forecast model and the dispersion model of the German Meteorological Service, it is possible to estimate future environmental contamination and likely radiation doses in the event of a radioactive cloud. These prognoses form the basis for specific emergency preparedness measures, such as behavioural recommendations for the general public. These measures can be announced by the relevant authorities in the country in question.

In Germany, in the event of a nuclear accident, the Federal Radiological Situation Centre (RLZ) uses RODOS results as the basis for assessing the situation and recommending protective measures. Internationally, this system is used by around 30 countries.