COVER STORY | ZAPORIZHZHIA OCCUPATION


on a nuclear plant have not been carried out. Furthermore, the safety of a reactor and the readiness of its safety systems depends not only on the integrity of the building but also on the power supply which was ‘almost completely disrupted’.


In addition, a reactor even in an undamaged building


Above: Unexploded ordnance was discovered within the grounds of the power station Photo credit: Energoatom


V out of control sparking catastrophe and in fear for the lives of their families in the town. They worked three eight- hour shifts in a row, as the new shift crew did not have the opportunity to arrive at the plant and relieve them.


The impact on safety By noon it was possible to make an initial assessment of the destruction. The administrative and training buildings were damaged by shelling, as well as other structures and systems. Unexploded ordnance was found within the station boundaries. There had been no radiation incident, but nuclear power


is characterized by a deeper understanding of safety. One of the important elements of this approach is the ‘almost happened event’ or near miss. What ‘almost happened events’ took place at the Zaporizhzhia nuclear plant on the night of 4 March? Various elements of the plant infrastructure were ‘almost


damaged and/or destroyed’: The power output system – open switchgear is located


directly behind the training building which was shelled. The central control room from which all unit and grid


electrical connections are controlled, as well as numerous cable routes with communication, control and protection lines.


The main unit transformers, when this fails all unit


systems switch to the backup power supply and, in its absence, to the emergency one if it is available. The emergency diesel generators, the complete failure of


which results in a nuclear accident during a unit blackout. When shells hit the turbine buildings, with their usual glazing and light roofs, the turbines were ‘almost damaged.’ Each of the four rotors weighs up to 200 tonnes and rotates at 1500 rpm. The tips of the turbine blades have a linear velocity close to the speed of sound and if they experience total failure their debris would destroy everything nearby, including the electrical systems used during normal operation that are located in the turbine halls. It is also possible that tonnes of lubricating oil from the turbine and control systems could catch fire and burn. The reactor buildings were ‘almost damaged’ and


as reactors are designed to withstand a plane crash, a tank attack cannot easily result in critical damage to the building. At the same time, tests with a real aircraft crash


20 | June 2022 | www.neimagazine.com


could be subject to negative impacts from the secondary circuit where destruction of the turbine leads to the damage of the main steam and feed water pipelines. Although there are designed-in protection and safety systems to manage such an event by isolating the steam generators and supplying cooling water, in the event of serious problems with both normal and emergency power supply it is impossible to guarantee their reliable operation. Any analysis of these events would not be complete without considering ‘almost damage’ to the dry spent nuclear fuel storage facility. There are 173 containers on the site, with 24 fuel assemblies in each. Yes, the assemblies are being stored in thick stainless steel casks set in concrete shells and very significant efforts will be required to damage the containers sufficient to release fission products into the atmosphere. This fuel has also been stored in cooling pools for many years and it is not as active as it once was, but it has spent three years in the core of a reactor.


With 163 fuel assemblies loaded into each VVER-1000


reactor, in total there are about 25 reactors worth of spent fuel at the storage site all of which was at significant risk that night. The impact on station’s operational personnel and their


role in safety should also be emphasised. The psychological state of personnel is one of the most important elements of nuclear safety and it is easy to understand how the events of late February and early March could significantly reduce the safety margin provided by this element. Although all these events ‘almost happened’, luckily they did not actually take place. Nonetheless, the plant and all its complex of scientific and engineering achievements was subjected to an unthinkable and many would consider insane military attack.


The situation now Since then, two long months have passed and the station and town are still occupied. Entry to and exit from the town is almost impossible and, aside from the Dnipro River, occupied territories stretch for 100km in all directions. The road to the nearest regional centre – Zaporizhzhia – goes through several Russian checkpoints. Passage through them is accompanied by thorough searches with uncertain consequences. There have been cases of confiscation of property and arrests. Cars have come under fire with fatal outcomes and fighting is taking place just 20 km from the road.


So-called green corridors to territory controlled by


Ukraine were agreed upon and organized several times for residents of Energodar. Some plant employees used this opportunity and sent their families to less dangerous locations but more than once people were turned back. All the large shops in the town are closed, though the situation is partly saved by small stores and market sellers they require cash and not a single bank branch is open. Despite such problems, there is electricity, water,


heating, as well as mobile communications and internet access, albeit with frequent disconnections. There are no


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