Strike near UAE reactor revives concerns over nuclear plant safety in wartime

A drone strike that cut off external power to a nuclear reactor in the United Arab Emirates this week has revived concerns over the safety of nuclear plants during wartime.

Reactor no 3 at the Barakah nuclear plant lost off-site power, which is critical for its own functioning, for about 24 hours after the attack on Sunday, forcing it to rely on emergency diesel generators.

Iran, or one of its regional proxies, is likely to have been behind the strike. One of three drones got through from the west, causing a fire close to a four-reactor plant that supplies the UAE with quarter of its electricity.

The UAE said the strike hit an electrical generator “outside the inner perimeter”, raising fears it could have hit the switch yard which lies just beyond a wall around the site’s reactors.

It is the first time a fully operating nuclear power plant has had to rely on backup generators as a result of a military attack, at a time when reactors in Ukraine and Iran are also threatened by war.

The UAE’s nuclear safety regulator said the attack did not cause any radioactive material to be released, though it was notable that it had not proved possible to completely defend a critical site from drones.

Experts told the Guardian there should have been sufficient power available from the other three reactors on-site, but this does not seem to have immediately been the case, possibly because of damage to the switch yard, which routes electricity in and out.

On Monday, the International Atomic Energy Agency said it had been told by the UAE that off-site power to unit No 3 had been restored “earlier today”, meaning that “the reactor no longer needs emergency diesel generators for power”.

Rafael Grossi, the head of the IAEA nuclear watchdog, said nuclear sites and other installations important for nuclear safety must never be targeted by military activity.

External power is critical to keep reactor cores sufficiently cool. All nuclear sites have backup generators to maintain power in an emergency, should the outside supply be lost.

At the Fukushima Daiichi nuclear plant in Japan, in 2011, three reactor cores melted down after a tsunami caused by an earthquake overwhelmed the backup generators. Though the fuel was contained, about 160,000 people had to be evacuated.