According to Ukrainian intelligence services, Russia is preparing an attack on the nuclear power plant near Zaporizhia. But how dangerous is such a plant still, now that the reactors have been shut down for months? ‘It is almost impossible to calculate those scenarios.’
Personnel must have left the plant by July 5 at the latest, and explosives are said to have already been placed around it: many worrying rumors are currently circulating about the nuclear plant at Zaporizhia, one of the largest in the world. Those rumors come from the Ukrainian military intelligence services and are as yet unconfirmed. For example, the International Atomic Energy Agency IAEA has so far no evidence seen for explosives at the nuclear power plant. And Russia denied earlier this month that there are plans to damage the plant.
“Much is still unclear, but this power station has already had an increased risk due to the war,” says Mark van Bourgondiën of the Dutch Authority for Nuclear Safety and Radiation Protection (ANVS). “The international community is watching closely.”
core melt
All six reactors at the plant are currently off. Two are empty; the rods with fissile material have been removed there. Two have been out for over a year and the last two since September.
However, the rods of nuclear fuel from the core remain hot even after a reactor has been turned off. They have to be cooled with (running) water for another five years to prevent them from melting. In such a so-called ‘core melt’, the radioactive material can leak into the environment. A part can also evaporate and end up in the air.
Fortunately, the heat from such rods decreases quickly after a reactor is turned off. “In the two reactors that were most recently active, the heat output is only one thousandth of when they were still on,” says Van Bourgondiën. If the cooling fails – for example because water pipes are damaged during an attack – countermeasures are still possible for several days.
No iodine tablets
If it does go wrong, then the good news is that the power plants have been off for some time. “Radioactive iodine, for example, has already expired,” says Lars Roobol of the National Institute for Public Health and the Environment. “So you don’t have to take iodine tablets.” However, there are other hazardous substances in the rods. “Radioactive cesium, for example, which can lead to soil contamination,” says Van Bourgondiën.
“Within a radius of about 10 to 20 kilometers around the plant there are potentially direct consequences for public health,” says Van Bourgondiën. People then have to take shelter for 48 hours and keep windows and doors closed. If you don’t, you will be exposed to radiation that leads to an increased risk of cancer. “It is about a percentage point at the most,” says Roobol.
By way of comparison: after the disaster at the nuclear power plant at Fukushima in Japan, the most affected civilians – except for aid workers at the nuclear power plant – received about ten times as much radiation as someone here receives in a year. “Everyone has an average 30 percent chance of dying from cancer anyway,” he says. At a dose ten times higher than in Fukushima, that is increased to 31 percent. “For local residents, it was therefore a fraction on top of that 30 percent,” he says.
on-stage
The released material can affect food safety up to a few hundred kilometers from the plant. “Radioactive material can attach to dust particles and soot particles and then rain down to the ground. It can end up in crops via the soil, or cows can eat it,” says Roobol. In that case, it can end up in our diet. “Then the material ends up in our bodies, instead of on the outside. That’s a bigger risk.”
The worst case scenario is a targeted attack on the power station itself. “It is almost impossible to calculate those scenarios,” says Van Bourgondiën. It is conceivable, for example, that the protective casings of the reactors become damaged, so that the material can more easily escape into the environment. Explosives can also cause a fire that is hotter than you might otherwise expect.
“The finer you crumble the radioactive material, the further it can go. And the warmer the material is, the higher it rises in the air,” says Roobol. That is, if, in addition to the damage caused by an attack, the cooling system also fails. Otherwise, the material will not end up in the environment at all.
In such a both-and scenario, the radioactive material can spread over a larger area. “Close windows and doors may even be necessary in a radius of 100 kilometers,” says Van Bourgondiën. Cows may even have to be stabled in neighboring countries. “In any scenario, however, there will be no consequences here.”
