A huge protective shield over the Chernobyl nuclear reactor in Ukraine no longer works as it should after a drone strike earlier this year, the International Atomic Energy Agency (IAEA) said. The shield was built over the 1986 disaster site to keep radioactive material locked in. The IAEA found the shield lost its "primary safety functions including the confinement capability." Ukraine blamed Russia for the attack in February, which Russia denies. The fire hit the outer steel part of the shield, but there was no damage to the main structure or monitoring equipment, and some roof repairs have been done. IAEA chief Rafael Grossi said, "Timely and comprehensive restoration remains essential to prevent further degradation and ensure long-term nuclear safety." Environmental expert Jim Smith from the UK told the BBC, "It is not something to panic about," explaining that the biggest danger is radioactive dust. But this dust is trapped inside a thick concrete sarcophagus, covered by the shield. The original sarcophagus was built after the disaster but was meant to last only 30 years. This new shield was meant to protect the site for the next 100 years. The IAEA has also been checking other parts of Ukraine's nuclear energy setup as Russia continues attacking the country. Grossi said electrical substations are vital to keep nuclear plants cool and safe, and to supply electricity to homes and industries.