The International Atomic Energy Agency (IAEA) has described the scale of the damage caused the February drone strike and subsequent fires at the New Safe Confinement (NSC) shelter, which protects the remains of Chornobyl NPP unit 4 destroyed in the 1986 disaster. The agency said that investigations continue to determine the extent of the damage.
The impact caused a 15-square-metre hole in the external cladding of the arch, with further damage to a wider area of about 200-square-metres, as well as to some joints and bolts. It took several weeks to completely extinguish the fires caused by the strike. IAEA said the emergency work resulted in approximately 330 openings in the outer cladding of the NSC arch, each with an average size of 30-50 cm.
According to information provided to the IAEA team at the site, a preliminary assessment of the physical integrity of the large arch-shaped building identified extensive damage, for example to the stainless-steel panels of the outer cladding, insulation materials as well as to a large part of the membrane – located between the layers of insulation materials – that keep out water, moisture and air.
In addition, the IAEA team was informed that the NSC’s main crane system (MCS), which includes the crane north maintenance garage area, was damaged by the drone strike and is currently not operational. The MCS is one of the building’s main systems. The crane maintenance garage area houses several electrical cabinets for various systems, most of which were affected by the drone incident and by the water used to put out the resulting fires.
The NSC’s other systems – providing relevant safety functions such as radiation monitoring, seismic monitoring, decontamination and radioactive waste management, power supply, and fire protection – continue to function, the IAEA team was informed.
While the heating, ventilation, and air conditioning systems remain functional, they are not in service after the drone incident, the Chornobyl site added. “We are gradually getting a more complete picture of the severe damage caused by the drone strike. It will take both considerable time and money to repair all of it,” according to IAEA Director General Rafael Mariano Grossi.
On a more re-assuring note, IAEA said there still has been no increase in radiation levels measured at the Chornobyl site, indicating there was no release of radioactive materials as a result of the strike.
The purpose of the NSC is to cover the ageing sarcophagus hastily built over the damaged reactor following the 1986 accident and to provide an environment where this crumbling structure could be safely dismantled. It will also make possible the eventual removal of the fuel-containing materials in the bottom of the reactor building and their characterisation, compaction, and packing for disposal. The NSC was financed through the Chernobyl Shelter Fund administered by the European Bank for Reconstruction & Development (EBRD). The fund received €1.6bn ($1.7bn) from 45 donor countries as well as €480m from the EBRD itself.
