The Russian Ministry of Defense stated that "in the event of a negative development of the situation" around the Zaporozhye nuclear power plant, the issue of stopping it could be considered. At the same time, the department traditionally blamed Ukraine for the shelling of the station, while the Ukrainian Energoatom blames Russia for what is happening.
“We would like to draw your attention to the fact that if the negative development of the situation related to the shelling of the nuclear power plant by Ukraine continues, the issue of putting the 5th and 6th power units into the “cold reserve” may be considered, which will lead to the shutdown of the Zaporizhzhya NPP,” said the head troops of radiation, chemical and biological (RCB) protection of the Russian Armed Forces, Lieutenant-General Igor Kirillov.
Andrey Ozharovsky, an engineer-physicist, an expert of the Radioactive Waste Safety program of the Russian Social and Ecological Union, explained in a conversation with The Insider that disconnecting a power unit from the grid and shutting down a reactor is a routine procedure that occurs every year and at every reactor. However, there are still risks: due to shelling at the nuclear power plant, the remaining power lines may be lost, which in theory can lead to a serious accident, because the safe shutdown of the plant does not occur instantly, but lasts about a week:
“Each nuclear fuel replacement reactor is shut down every twelve or eighteen months. This is not a disaster, this is done by the operators on a regular basis. If the reactor is correctly brought to a cold "shutdown", then it will then be possible to start it back up, this does not mean that it has been killed and that's it, it is no more.
The reactor does not stop instantly: there is residual heat, and in order for the reactor not to melt, it is required to cool it, i.e. pump water through it, which requires an external source of electricity. Since the scenario of an accident with the loss of the final heat sink is well known to nuclear scientists, there are backup systems. There should be more power lines than the power that the nuclear plant produces in case one of the power lines fails or is under repair.
We have seen reports that power transmission towers have been destroyed, and the nuclear plant is now on the same power line. This is unacceptable, because the reserve must be two- and three-fold. If something happens to the rest, then the nuclear power plant may be left without an external source of energy. Power lines are very easy to damage, they cannot be hidden, everyone knows where they are, they cannot be protected from saboteurs. If the nuclear power plant loses all power lines, then the reactors must be shut down and backup diesel generators must be started, then everything will be fine. If they do not turn on, then it will be what was at Fukushima. There, after the earthquake, the reactors were regularly shut down by automation and operational personnel, and when cooling was required, a wave came and washed away the backup diesel generators that were in an unprotected place – and this is how we got the largest radiation accident after Chernobyl. Unfortunately, the Fukushima scenario will be very close, if the station is de-energized and there is nothing to remove the residual heat (and this should be done for about a week), then the reaction of melting the reactor core is quite possible, and this is a severe radiation accident.
According to Ozharovsky, a nuclear power plant can be in a "silted" state for years and even decades: "It may be necessary to unload nuclear fuel, perhaps not." “As far as I know, there is not such a huge demand for electricity in Ukraine, and I have the impression that the complete and long-term shutdown of the Zaporozhye NPP, the transfer of reactors to a cold “shutdown”, is rather a blessing (due to safety issues), although, of course consumers will have to look for other sources of energy.
However, there is another problem that the scientist draws attention to: chips were found on local spent fuel storage facilities (very dense concrete containers). These containers contain spent nuclear fuel , which is the most dangerous and highly radioactive. According to Ozharovsky, the destruction of these containers is comparable to the destruction of reactors.
