February incident caused major fire in outer cladding of massive steel structure
A comprehensive safety assessment of the New Safe Confinement (NSC) at the Chernobyl nuclear site in Ukraine has shown it had lost its primary safety functions, including the confinement capability, following a drone strike in February, the International Atomic Energy Agency said.
The agency said a team completed the assessment of the NSC last week.
The drone strike on 14 February pierced a large hole through the roof of the €1.5bn ($1.7bn) NSC, which was built to prevent any radioactive release from the destroyed Unit 4 reactor and protect it from external hazards.
The event also caused a major fire in the outer cladding of the massive steel structure built to prevent any radioactive release from the reactor destroyed in the 1986 accident.
The IAEA assessment confirmed that the NSC had lost its primary safety functions, including the confinement capability, but also found that there was no permanent damage to its load-bearing structures or monitoring systems.
“Limited temporary repairs have been carried out on the roof, but timely and comprehensive restoration remains essential to prevent further degradation and ensure long-term nuclear safety,” IAEA director-general Rafael Grossi said.
Based on the mission findings, the IAEA has recommended further restoration and protective work of the NSC structure, including humidity control measures and an updated corrosion monitoring programme, as well as an upgrade of an integrated automatic monitoring system for the shelter object structure built on top of the reactor immediately after the accident.
In 2026, with support from the European Bank for Reconstruction and Development (EBRD), the Chernobyl site will undertake additional temporary repairs to support the re-establishment of the NSC’s confinement function, paving the way for full restoration once the conflict ends.
“The IAEA – which has a team permanently at the site – will continue to do everything it can to support efforts to fully restore nuclear safety and security at the Chernobyl site,” Grossi said.
The IAEA also said an agency team is criss-crossing Ukraine this month to assess the status of electrical substations critical for nuclear safety and security, following recent military attacks targeting energy infrastructure.
The 1-12 December is focussing on more than 10 substations – essential nodes in the electrical grid related to the nuclear power plants – to assess the damage, review repair efforts, and identify practical steps to strengthen the resilience of offsite power supplies to the country’s nuclear stations, three of which – Khmelnitski, Rivne and South Ukraine – are still operating to generate electricity.
