RESUMO
The better knowledge of the mechanisms of nuclear incidents and lessons learned from accidents in the recent past to improve the effectiveness of measures taken following a nuclear accident exposure to fallout of radioactive iodine isotopes. Thus, immediate, passive measures, such as containment, and stopping consumption of contaminated products are paramount. The earliest possible administration of stable iodine as potassium iodide (KI) reduces significantly (up to 90% if taken at the same time of the accident) thyroid radioactive contamination. These tablets should be given in priority to children and pregnant women. The side effects are minor. KI is not recommended for persons aged over 60 years, or for adults suffering from cardiovascular disorders.