What inspectors will look for at Ukraine's war-damaged Zaporizhzhia nuclear plant

Inspectors for the International Atomic Energy Agency have been to some of the world's most sensitive nuclear facilities — from North Korean reactors to Iranian uranium plants. But it all seems straightforward compared to what awaits them at the Zaporizhzhia Nuclear Power Station in southern Ukraine.

Since March, the plant has been occupied by Russian forces, and run by a skeleton crew of Ukrainian workers. When they arrive, inspectors will walk past the boarded-up hulk of the main administrative building, which was pummeled by rocket-propelled grenades during the initial invasion. A nearby courtyard holds the charred remains of military tents, razed by a retaliatory Ukrainian drone strike in late July. In recent weeks, shells have punched through the roofs of vital support buildings, and wildfires have threatened the plant's power lines.

It's all happening at a nuclear facility — Europe's largest — that even in peacetime can be daunting, says Lars van Dassen, the executive director of the World Institute for Nuclear Security, a nonprofit in Vienna. Van Dassen has visited Zaporizhzhia, and says its six massive reactors and sprawling auxiliary buildings make the site a challenge to navigate.

"It's very hard to find your way around if you don't have a guide," he says. Add in the fact that the plant is now on the front lines, and "this is the environment that I cannot imagine the IAEA has ever been in before."

The world's nuclear watchdog has its work cut out

The International Atomic Energy Agency is the world's nuclear watchdog. In the past, it has been charged with making sure that nations do not illicitly pursue nuclear weapons. Inspectors have caught inconsistencies in North Korea's plutonium inventories, and checked that Iran's uranium enriching centrifuges are not producing bomb-grade material.

But the agency also conducts more run-of-the-mill inspections at nuclear power stations all over the world, according to Shirley Johnson, a former nuclear inspector with the agency who now runs a U.S.-based private consultancy.

Though important, "the most boring inspection you can do is a power plant," Johnson says. Inspectors typically check the books and make sure the reactor's inventory of nuclear fuel and nuclear waste matches what's on paper. They'd also make direct measurements to ensure that the nuclear material is really what it's reported to be. Normally "you can do a power reactor in half a day," Johnson says.

The IAEA has been to Zaporizhzhia many times before on these routine missions, says Kevin Veal, the head of international nuclear safeguards at the U.S. National Nuclear Security Administration. "The agency has had a really good handle on activity at the facility for well over two decades," he says, referring to the IAEA.

This inspection is far from routine, however. The inspectors' visit was delayed for months, until the latest fighting around the plant put enormous diplomatic pressure on Russia, according to Patricia Lewis, the director for international security at Chatham House in London.

During a United Nations Security Council meeting last week, even China said that the nuclear inspectors should be allowed to visit the nuclear plant. "It was stark," Lewis says. "Every other country basically said you should let in the IAEA."

It's hard evaluating plant security in a war zone

The Zaporizhzhia mission is also technically more complex than previous missions. In addition to making sure that the plant's large stocks of nuclear fuel and nuclear waste haven't been diverted or altered since Russian forces took the plant in the spring, inspectors are going to be looking at how the reactors and their safety systems are holding up. They will likely check for things like whether the diesel generators have enough fuel to keep running if the lights go out at the plant, as they did last week. The generators are vital because water must continuously flow through the reactor cores to keep the nuclear fuel cool, even after the reactors have been shut down.

The mission will also look at security around the plant. Van Dassen says that job would typically include reviewing whether systems like ID card readers and remote cameras are working. But Johnson says, given the ongoing fighting around the facility, it may be difficult to evaluate. "There certainly is no security at this time," she says.

Perhaps most importantly, the inspectors will be talking to Ukrainian workers at the plant. A skeleton crew of Ukrainians have been running the power station, reportedly while being harassed and abused by Russian troops. Johnson says it's important to find out how they're doing, but that will also be the most difficult part of the inspection.

"It kind of depends whether the Ukrainian operators are able to speak truthfully and openly," she says.

The agency chief wants to keep a permanent mission there

Rafael Mariano Grossi, director general of the IAEA who is leading the mission to Zaporizhzhia, says that he has been assured that he will be able to interview Ukrainian staff. "Of course that is one of the most important things, and I will do it," he told reporters at a brief press conference on Wednesday.

Veal, at the National Nuclear Security Administration, says the information this mission will bring back will be vital to understanding the situation at the plant. "It's one thing to have satellite images, it's another to have people on the ground," he says.

The inspection will also deliver a third-party evaluation of the plant, Johnson, the former nuclear inspector, says. "The world will get some information that you don't feel is biased one way or the other," she says.

Grossi also said he hopes the IAEA will be able to establish a permanent presence at the Zaporizhzhia plant, to ensure that the world continues to know exactly what's happening there.

Nuclear security expert van Dassen says keeping inspectors in a war zone would be even tougher than this brief visit.

But, he adds, putting inspectors at the nuclear plant might be the only thing that keeps the two sides from shooting at it. "If there is one thing that could maybe bring a difference, then it would be something like that."

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