Saturday, April 1

MAP | The 15 nuclear reactors in Ukraine: where they are and what danger they pose

As the Russian offensive on Ukraine progresses, concern is growing about the risk that attacks on the 15 nuclear reactors that exist in the country may pose. After the capture of Chernobyl by Russian troops, this Friday, at dawn, they bombed the Energodar plant, in the Zaporizhia region: it is the largest nuclear power plant in Europe. The attack sparked a huge fire that burned for hours. Finally the fire was extinguished, the Russian troops took over the plant and the staff guaranteed “its proper functioning” with “stable” radiation levels.

The 15 reactors are divided into four nuclear power plants: Khmelnitsky (2), Rivne (4), South Ukraine (3) and Zaporizhia (6), according to the latest data from the Ukrainian operator Energoatom.

According The IAEA (International Atomic Energy Agency) has reported In a statement, of the six units of the attacked plant in Zaporizhia, Unit 1 was shut down for maintenance, Units 2 and 3 have been shut down in a controlled manner, Unit 4 is operating at 60% power and Units 5 and 6 are kept “in reserve” in low power mode.

The director general of the UN nuclear agency, the Argentine Rafael Grossi, has shown concern with the situation at the plant, which “is unprecedented”, and although there have been no radioactive leaks, he has indicated that “firing projectiles into the area of ​​a nuclear power plant violates the fundamental principle of maintaining the physical integrity of nuclear facilities.”

The IAEA has ruled out that Ukraine is developing nuclear weapons, as Russia alleges, among other things, to justify its invasion of the neighboring country.

Danger due to its age

All 15 operational reactors in Ukraine are pressurized water reactors (PWRs). As explained by the Nuclear Safety Council (CSN) on its website, in this type of reactors, the water circulates through the “primary circuit” at very high pressure thanks to “pumps that propel it through the reactor core”. The pressure prevents it from reaching the boiling point and from forming vapor in the primary circuit. The water in the primary circuit then heats the water in the secondary circuit until it turns into steam, which is what subsequently turns the turbine. The rotation of the turbine is transmitted to the electric generator that produces electricity.

The IEAE (International Atomic Energy Agency) says that Ukraine’s nuclear reactors are a critical element for electricity supply, since they provide almost half of the country’s electricity. All of them have a power of 950 megawatts except for two of those located in Rovno, with a power that does not reach 400 megawatts.

as collected the World Nuclear Association, all the reactors are of the Russian VVER type, a model that was developed by the former USSR in the 1980s. Twelve of them were designed to have a useful life of 30 years, so they should have come to an end before 2020. However, the Ukrainian state-owned company Energoatom was then willing to extend its life for another 10 years and licenses for its activity were issued.

Nuclear safety experts warn of the danger posed by the age of these reactors. Ukraine’s aging nuclear power plants require maintenance and monitoring that may be affected by attacks. Bob Rosner, a physicist at the University of Chicago, explained to Wired magazine that most of the nuclear plants in Ukraine began to be built in the 1980s. Steel is their main component, but when bombarded with neutrons for many years “it becomes brittle and can break” so they need “monitoring”. constant”.

Possible failure due to power supply

Apart from the danger that a direct attack on one of these plants, such as the one that occurred in Zaporizhia, could pose, there is another risk, which is that the supply of electricity that the plants need to function fails. If there are power outages and standby generators fail, the cooling system could fail and cause an accident that releases radioactive material.

In this sense, Patricia Fernández, spokesperson for the CSN, explained to the EFE agency that the Ukrainian plants are prepared for the risk of loss of electricity supply given that “it is a member country of the Association of European Nuclear Regulators (WENRA).”

To counteract the loss of external power, “the plants have emergency diesel generators capable of operating autonomously for several days”, so this threat should not pose a risk to the plants.

In addition, “after the Fukushima nuclear accident in 2011, additional measures were implemented to deal with the total loss of alternating current”, that is, “not only from the external electricity supply, but also from the diesel generators” that could keep the generators active. refrigeration systems, according to Fernández.

However, an analysis of the environmental organization Greenpeace warns that “when the power grid fails and the reactor is in a power plant blackout, there are diesel generators and backup batteries, but their reliability cannot be guaranteed for a longer period of time. There are ongoing unresolved issues with Zaporizhia’s emergency diesel generators, which have an estimated fuel stock on site for only seven days.

“Potentially much worse than Fukushima”

Greenpeace notes that “according to official data from 2017, there were 2,204 tonnes of high-level spent nuclear fuel in Zaporizhia, 855 of which were in highly vulnerable spent fuel pools. Without active cooling, they are at risk of overheating and evaporating to a point in which the metal cladding of the fuel could catch fire and release most of the radioactive inventory.”

It could render a large part of Europe, including Russia, uninhabitable for many decades and for a distance of hundreds of kilometres, a nightmare scenario and potentially much worse than the 2011 Fukushima disaster.


Furthermore, “if the containment were destroyed by explosions and the cooling system failed, radioactivity from both the reactor and the fuel pool could freely escape into the atmosphere. This would risk rendering the entire plant inaccessible due to high levels of radiation, which could then lead to a further cascade from the other reactors and fuel pools, each of which would spread large amounts of radioactivity in different wind directions for several weeks, could make a large part of Europe , including Russia, would be uninhabitable for at least many decades and for a distance of hundreds of kilometers, a nightmare scenario and potentially much worse than the Fukushima disaster of 2011,” warn environmentalists, who are actively opposed to nuclear energy.

James Acton, co-director of the nuclear policy program at the Carnegie Endowment for International Peace, explained on Twitter that nuclear power plants have “layered” safety mechanisms, making it difficult for all of them to fail. However, the situation in a war zone is unpredictable and “the unimaginable becomes completely conceivable”.