Radiation situation in Ukraine

The war in Ukraine does not affect the radiation situation in Finland. Nor can any accident or damage related to radioactive materials or nuclear power plants in Ukraine cause a situation in which people in Finland need to be protected from radiation.

Ukraine has four active nuclear power plants (Hmelnytskyi, Rivne, Zaporizhzhia and Southern Ukraine) with a total of 15 reactors. Even if the nuclear power plants in use in Ukraine were badly damaged, the serious radiation effects would not reach Finland.   

However, an accident or damage to a nuclear power plant in Ukraine could cause large local discharges if the containment building around the reactor was damaged at the same time. Radioactive substances could pollute the surroundings of the plant and people close to the plant could develop an illness from radiation and radioactive substances. However, there would be no significant dispersion of radioactive substances over a radius of more than 200 km from the accident.   

Nuclear power plants are generally quite strong constructions, as they have to tolerate many extreme natural events. The multiple safety systems of nuclear power plants are capable of ensuring safety even if some part of the plant were damaged. However, nuclear power plants for civil use are not designed to withstand military attacks.   

In addition to direct attacks on nuclear power plants, indirect impacts could occur. The operability of the electricity grid and plant maintenance, for example, as well as the ability and possibility of the personnel to look after the plant are vital in view of safety. For example, paralysing the Ukrainian electricity grid would affect the operation and production of nuclear power plants. Nuclear power plants would then have to operate with a standby supply system for significantly longer periods than in the case of normal disturbances.   

STUK has no detailed information about the plants in Ukraine and their design criteria, or more detailed information about the preparedness and protection of nuclear power plants in Ukraine against intentional damage.   

In any case, the Ukrainian nuclear power plants are water-cooled plants with the same basic structure as the Loviisa nuclear power plant in Finland. An accident such as the one in Chernobyl in 1986 is not possible in them. The Chernobyl reactor used graphite as the moderator, the combustion of which raised radioactive substances high into the air and subsequently spread them over a very large area through the air currents.   

International conventions require that nuclear power plants are not attacked or damaged intentionally. An additional protocol to the Geneva conventions relating to the Protection of Victims of International Armed Conflicts in the Geneva outlaws military attacks on dams, dikes, nuclear power plants and other corresponding plants that would cause danger if damaged even if they were used for military purposes. This convention has been clearly violated several times during the war in Ukraine in the Chernobyl area and at the Zaporizhzhia nuclear power plant, for example.

Zaporizhzhia nuclear power plant

The six reactors of the Zaporizhzhia nuclear power plant have not been in full power operation since fall 2022. All reactors are currently generating much less decay heat than they would if the power plant was producing electricity at full capacity. According to the Ukrainian authority, SNRIU, five of the plant’s reactors are placed in cold shutdown and one reactor is placed in hot shutdown. The reactor in hot shutdown can be used to produce heat for the plant’s own use, even with the reactor shut down. An accident or damage to the Zaporizhzhia nuclear power plant could result in a release to the immediate surroundings of the plant if the containment building of one or several reactors were damaged at the same time. However, there would be no significant dispersion of radioactive substances over a radius of more than a few dozen kilometres from the accident.

In the case of a possible situation requiring protection of population, no iodine tablets would be needed in Ukraine or elsewhere in Europe, because the radioactive iodine produced in the fission reactions in the Zaporizhzhia nuclear power plant has already decayed almost completely during the cold shutdown (the half-life of iodine is eight days, and dozens of half-lives have already taken place).


The Chernobyl nuclear power plant is located in the northern part of Ukraine. One of the four reactors of the plant was destroyed in 1986. A protective dome has been built on top of the destroyed reactor. The other three reactors have been permanently shut down and the fuel has been removed from their reactors. The Chernobyl area also has storages of spent nuclear fuel and other nuclear waste. The spent nuclear fuel stored in the Chernobyl area is still very radioactive. However, it has been cooled down for a long time and there is virtually no risk of radioactive substances spreading over a very large area. 

The Chernobyl plant area is surrounded by a 30 km exclusion area, whose soil and vegetation still contain radioactive substances from the accident. The dose rate caused by external radiation there has remained high since the 1986 accident. Radioactive substances in the soil may be released into the air by movement in the area, for example, causing a momentary rise in radiation levels. Radioactive particles are heavy, as dust from the area is bound to the particles, and they do not travel long distances. 

Radioactive substances elswhere in Ukraine

There are radioactive substances in research institutes and in storages for radioactive waste recovered from places other than nuclear power plants in different parts of Ukraine. The waste in the storages is mainly low-level waste from hospitals and industry.

Iodine tablets and how to take them

The authorities permanently recommend that people should have iodine tablets in their medicine cabinets at home for a possible radiation accident. Taking iodine tablets in the event of a radiation hazard situation due to a nuclear accident is recommended for people up to 40 years of age and pregnant women. When taken at the right time and in the correct doses, iodine protects the thyroid gland and reduces the risk of thyroid cancer. The situation in Ukraine has not affected this recommendation nor is there any special reason to purchase iodine tablets now.

Above all, iodine tablets must not be taken without instructions from the authorities. You should never take an iodine tablet ‘just in case’, as it is important to take the iodine tablet at the right time. The protective effect of the tablet is reduced if the tablet is taken too early or too late.

More information about iodine tablets

Additional information

Frequently asked questions

The Radiation and Nuclear Safety Authority has received a large number of questions related to the situation in Ukraine. We have compiled some of the most frequently asked questions and answers to them on this page.