Slow leak of radiation due to failure of cooling system the big nuclear worry a more realistic danger for nuclear plants in this war

The consensus from the experts is that there was no real danger of an explosion at the Zaporizhzhia plant.

Even if the shells that hit the administration block had targeted any of the six reactors instead, they were in containment structures made to withstand considerable force.

The reactors are also different to those at Chernobyl, less volatile and easier to control.

It’s just as well. A chilling exhibit at the Chernobyl Museum in Kyiv records the movement of the radioactive cloud across Europe in the two weeks following the 1986 explosion there.

It reached Ireland twice, and Zaporizhzhia is many times bigger and more powerful than Chernobyl.

But it is not an explosion and sudden release of radiation that causes scientists most concern.

It is the disruption of the support systems required for the safe running of Ukraine’s five nuclear plants.

The day before the attack on Zaporizhzhia, Olexiy Pasyiuk, deputy director of environmental group Ecoaction Ukraine, expressed fears about fighting close to plants in an online briefing for European journalists.

“You don’t necessarily have to target the reactors themselves because the cut-off of electricity supply causes difficulties for plants to operate,” he said.

“They would have some back-up but it’s designed only for days. The accidents we saw in other places often related to the systems.

“So we have a very real danger of a nuclear accident at one of the plants.”

Scientists now echo those worries. “The real concern is not a catastrophic explosion as happened at Chernobyl but damage to the cooling system which is required even when the reactor is shut down,” said Professor David Fletcher of the University of Sydney and formerly UK Atomic Energy.

“It was this type of damage that led to the Fukushima incident.”

Senior nuclear advisers at Greenpeace agree.

“A nuclear power plant that is in operation requires active systems to remain functioning at all times,” they said.

“This includes many aspects, not only electricity but also cooling water and the continuous presence of qualified personnel. Even under normal functioning, hundreds of workers need to be able to reach the plant from their homes, which is evidently not feasible under war circumstances.”

Another major concern is the spent fuel stored on site.

At Chernobyl, prior to the war, security guards were at ease as visitors photographed the poignant memorials and the bomb-proof superstructure completed in 2019 to contain the damaged reactor, but they quickly blocked attempts to capture a dilapidated structure nearby.

It holds thousands of spent but still highly radioactive nuclear fuel rods, kept cool in water as was the crude technology of the early 1980s.

The building is not a bomb-proof superstructure. It looks barely weatherproof now.

A project to create a new safe containment facility some miles away with special trains to transport the delicate cargo is years behind schedule.

Transfers were due to begin next month but the plant is now in Russian control.

Zaporizhzhia also has hundreds of tons of spent fuel on site, some stored in similarly fragile conditions and some in a more modern, dry facility.

“There is a spent nuclear fuel storage facility, damage of which due to shelling will also lead to radioactive releases,” the State Nuclear Regulatory Inspectorate of Ukraine said bluntly yesterday.

The inspectorate reported normal radiation levels at all plants but EU monitors are not leaving it up to the locals.

All EU countries have a national nuclear safety regulator. In Ireland, it is the radiological protection unit within the Environmental Protection Agency (EPA).

It conducts 24-hour monitoring of radioactivity levels at 40 locations on land and in the Irish Sea.

Data is shared among European regulators and the EPA also receives data from Britain through an agreement that has survived Brexit.

If any spike in radiation is detected, it will spark a series of swift assessments.

Depending on how high it is, where it is and weather conditions, the Government may activate the National Plan for Nuclear and Radiological Emergency Exposures.

Advice messages will be issued through all media outlets, including social media which, given the reaction in the early hours of yesterday morning to events in Zaporizhzhia, could be a crowded arena.

The Irish public is not displaying outward signs of worry at present.

While there were reports in other EU countries of a surge in sales of iodine tablets, the Irish Pharmacy Union said its members had observed no such trend.