A protective shield covering the Chernobyl nuclear reactor in Ukraine can no longer provide its main containment function following a drone strike earlier this year, according to a UN watchdog.

International Atomic Energy Agency (IAEA) inspectors found that the massive structure, built over the site of the 1986 nuclear disaster, had lost its primary safety functions including the confinement capability.

In February, Ukraine accused Russia of targeting the power plant - a claim the Kremlin denied.

The IAEA said repairs were essential to prevent further degradation of the nuclear shelter. However, environmental expert Jim Smith told the BBC: It is not something to panic about.

Prof Smith from the University of Portsmouth in the UK, who has studied the aftermath of the Chernobyl disaster, stated that the biggest danger linked to the site is possibly disturbing radioactive dust. Yet he emphasized that the risk is low because contaminated dust is contained within a thick concrete sarcophagus covered by the protective shield.

The 1986 explosion at Chernobyl blasted radioactive material into the air, triggering a public health emergency across Europe. In response, the former Soviet Union constructed the sarcophagus over the nuclear reactor.

The sarcophagus has only a 30-year lifespan, necessitating the protective shell to prevent radioactive material leaking out over the next 100 years.

The IAEA recently completed a safety assessment of the site after it was severely damaged by the drone strike, which caused a fire in the outer cladding of the steel structure.

Inspectors reported no permanent damage to the shell's load-bearing structures or monitoring systems, and some repairs had been made to the roof. Nevertheless, IAEA director general Rafael Grossi asserted that timely and comprehensive restoration remains essential to prevent further degradation and ensure long-term nuclear safety.

Since the beginning of December, the UN's nuclear watchdog has been evaluating Ukraine's energy infrastructure amid the ongoing conflict with Russia. Grossi highlighted the critical need for operational electrical substations linked to nuclear safety for reactor cooling and overall plant functionality.