Wedged between the front line and the Dnieper River, the Zaporijjia nuclear power plant, located in Enerhodar, is at the heart of all negotiations in the context of the war led by Russia in Ukraine.
Taken by the troops of Vladimir Poutin, the installations concentrate the concerns because of the bombardments close to the infrastructures. Is there a risk of nuclear catastrophe? Could an artillery strike devastate one of the six reactors of Europe’s largest power plant?
A mission from the International Atomic Energy Agency (IAEA) arrived at the plant on Thursday 1 September. After a short visit, the director of the UN body Rafael Grossi was able to observe that “the physical integrity of the plant has been violated on several occasions”. “This is something that cannot continue to happen”he was alarmed, indicating that IAEA inspectors will remain on site for at least a few days.
Fears of power loss
The reactors of the Zaporijjia power plant and the pools which ensure their cooling are protected by concrete confinement enclosures, one meter thick, and reinforced by an iron frame.
“These protective domes are designed to limit radioactive releases inside but also to protect the reactors from external attacks such as the fall of an airplane.explains Karine Herviou, deputy director general of the nuclear safety center at the Institute for Radiation Protection and Nuclear Safety (IRSN). They offer a certain robustness in the event of a direct attack on the building with conventional shells. But some keystrokes could create problems depending on their load. »
The concerns of the experts are more focused on the power supply of the plant, which allows the operation of the pumps which regulate the temperature inside the reactor. “Of the four main lines that supply the plant, only one has not yet been cut”reports Karine Herviou.
Even in the event of such a failure, safety mechanisms are in place. “Reactors can initially self-fuel by dropping power in secondscontinues the IRSN expert. If this does not work, each of the six reactors has three generators capable of taking over for 7 to 10 days without outside intervention. » These standards were reinforced in particular following the Fukushima disaster in 2011.
Other more fragile infrastructures
“However, we do not know the state of the generators or the state necessary fuel reserves on site »she worries, judging the situation “very worrying”. The management of the plant’s personnel, whose working conditions have deteriorated since the arrival of Russian troops, is also a reason for concern, as is the availability of the parts needed for maintenance or the access of specialized service providers to the enclosure of the facilities. These are the points on which the IAEA inspectors are looking.
A nuclear power plant does not only house reactors and water reserves. “At Enerhodar, other buildings much less protected than the reactors are also sensitiveemphasizes Karine Herviou. There are waste treatment areas where radioactive spent fuel assemblies are stored. The packages that protect them are less solid than the containment enclosures and the buildings were hit by strikes in early August. »
Damaged, these protections could leak limited radioactive releases. A risk highlighted by Energoatom, the Ukrainian operator of nuclear power plants, last month. For the time being, none of the sensors placed around the plant have detected an abnormally high rate of radioactivity. “One would expect limited releaseswarns Karine Herviou. But an accident of this type would however be much less serious than the meltdown of a reactor. »
Four of the six reactors were shut down at the plant, two of which have been shut down since the start of the Russian invasion. Thursday morning, before the arrival of the IAEA mission, a bombardment forced Energoatom to urgently arrest a fifth.