Actions in a radiation hazard situation

Instructions for members of the public in the event of a radiation hazard situation

Finland has never had a radiation hazard situation in which there was a need to, for example, protect oneself indoors or take iodine tablets. However, the authorities are prepared for a radiation hazard, and the operations are regularly practised. In the event of a radiation hazard situation, the protective measures taken by the authorities aim to prevent and limit the public's exposure to radiation. The objective is to minimize the stochastic effects of radiation (cancer) to the extent possible, as well as to prevent the direct health hazards caused by radiation (e.g. radiation injuries, radiation sicknesses).

Read more about the different operators and their duties on the Authorities cooperate in the event of a radiation hazard situation page.

Radiation hazard situation and protective measures

A radiation hazard situation refers to a situation in which the consequences of an event may require special measures to limit or reduce the radiation exposure of members of the public or of persons participating in emergency work and protective measures.

Protective measures are measures that aim to keep the radiation exposure of the population as low as possible in the event of a radiation hazard situation, to keep other harmful effects caused by the situation as low as possible, and to restore the living conditions of people and the functioning of society to as normal as possible after the radiation hazard situation.

STUK’s duties in a radiation hazard situation

The duties of the Radiation and Nuclear Safety Authority include preparedness and expert tasks in the radiation hazard situation. STUK forms a situational picture of the event and determines the danger zone. STUK also assesses the adverse effects of the situation on the population and the environment and makes recommendations on the necessary protective measures. In addition, STUK advises, for example, the industry, trade and transport and customs authorities in reducing the harmful effects and investigates the need for restrictions on the use of foodstuffs.

Radiation hazard situations are divided according to their temporal phase into the early phase, intermediate phase and recovery phase.

Laki Säteilyturvakeskuksesta (Act on the Radiation and Nuclear Safety Authority) ( ​​​​​​​

Protective measures in the early phases of a radiation hazard situation

In radiation hazard situations in which there is a risk of radioactive substances being released or in which they have been released into the air, protective measures are taken even before the radioactive substances arrive in the area. The key protective measures are staying indoors, access restrictions, and evacuation from the immediate surroundings of the incident. Taking iodine tablets is a supplementary protection measure to staying indoors in accidents in which radioactive iodine is released. These measures are used to limit the immediate radiation exposure of humans. Furthermore, agricultural production, other production and various premises must be protected to reduce contamination.

In a local radiation hazard situation, the area is isolated and evacuated. An example of such a situation is a hazard caused by an unshielded radiation source with effects limited to the immediate vicinity of the incident or indoors. A local radiation hazard situation may be caused by an accident in the use or transport of radioactive substances or by intentional unlawful use of radioactive substances.

Employee safety

In the event of an accident, employees involved in rescue and protection operations may be exposed to radiation to a greater extent than the rest of the population. Protective measures to avoid direct damage to health concern first and foremost those rescue workers who have to work in the immediate vicinity of strong radiation sources.

The employer is responsible for the radiation protection of employees engaged in radiation practices. Protective measures must be taken so that the employees will not be exposed to radiation unnecessarily. The goal is that the employee's dose does not exceed 20 millisieverts (mSv) per year. Before starting a task, the extent of exposure is assessed and monitoring of the accumulation of the dose during the work is planned. If no personal dosemeters are used, the radiation dose is assessed by measuring the dose rate of external radiation.

Rescue and protective personnel must wear protective clothing and respiratory filters. If it is possible that there is radioactive iodine in the air in the contaminated area, preparations are also made to take iodine tablets.

Protective measures in the intermediate phase of a radiation hazard situation

In the later stages of the radiation hazard situation, the radiation level in the living environment no longer rises and no new releases of radioactive substances are expected. In the later stages, it will be decided whether the protective measures implemented in the early stages can be lifted, eased or changed. Furthermore, new protective measures to reduce radiation exposure and the amount of radioactive substances in the living environment are launched, if necessary. These measures aim to ensure the radiation safety of people and the continuation of society’s critical operations.