Despite more than a year of warnings that critical Ukrainian nuclear energy infrastructure sites are vulnerable to potential Russian attacks, Ukraine's Energy Ministry has failed to act swiftly to protect them,

International Atomic Energy Agency (IAEA) chief Rafael Grossi arrived in Kyiv on Tuesday and inspected an electricity distribution substation, warning that attacks on Ukraine's power grid could pose a risk of a nuclear accident by disrupting supply.

Only in the fall, after Ukrainian intelligence agencies warned of potential strikes targeting nuclear transmission facilities, was action taken to begin building protection, the officials said — far too late in the event of an attack.