The protective shield over the Chornobyl disaster nuclear reactor in Ukraine, which was hit by a drone in February, can no longer perform its main function of blocking radiation, the International Atomic Energy Agency (IAEA) has announced.

In February a drone strike blew a hole in the “new safe confinement”, which was painstakingly built at a cost of €1.5bn ($1.75bn) next to the destroyed reactor and then hauled into place on tracks, with the work completed in 2019 by a Europe-led initiative. The IAEA said an inspection last week of the steel confinement structure found the drone impact had degraded the structure.

The 1986 Chornobyl explosion – which happened when Ukraine was under Moscow’s rule as part of the Soviet Union – sent radiation across Europe. In the scramble to contain the meltdown, the Soviets built over the reactor a concrete “sarcophagus” with only a 30-year lifespan. The new confinement was built to contain radiation during the decades-long final removal of the sarcophagus, ruined reactor building underneath it and the melted-down nuclear fuel itself.

The IAEA director general, Rafael Grossi, said an inspection mission “confirmed that the [protective structure] 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”.

Grossi said some repairs had been carried out “but comprehensive restoration remains essential to prevent further degradation and ensure long-term nuclear safety”.

The UN reported on 14 February that Ukrainian authorities said a drone with a high explosive warhead struck the plant, caused a fire and damaged the protective cladding around the reactor. Ukrainian authorities said the drone was Russian. Moscow denied it had attacked the plant.

Radiation levels remained normal and stable and there was no reports of radiation leaks, the UN said in February.

Russia occupied the plant and the surrounding area for more than a month in the first weeks of its February 2022 invasion of Ukraine as its forces initially tried to advance on the Ukrainian capital, Kyiv.

The IAEA had conducted the inspection at the same time as a country-wide survey of damage to electricity substations from the war between Ukraine and Russia.

With Reuters