Chernobyl Radiation Detectors Are Back Online for First Time Since Russia’s Invasion

Radiation detectors at the defunct Chernobyl nuclear power plant in Ukraine are back online for the first time since the Russian invasion more than 100 days ago, and radiation levels are normal, the head of the international nuclear watchdog agency said Wednesday.

Rafael Mariano Grossi, director general of the International Atomic Energy Agency, called the resumption of radiation data transmission “a very positive step forward for nuclear safety and security in Ukraine.”

“It ends a long period of virtual information blackout that created much uncertainty about the radiation situation in the area, especially when it was under Russian occupation,” he said.

The detectors stopped working Feb. 24, the first day of the invasion. Russian forces set up encampments and dug trenches in the forests around the plant, the site of the world’s worst nuclear disaster in 1986. Russian troops left March 31.

Grossi and international experts have expressed alarm over the safety of Ukraine’s nuclear reactors. This week, Ukraine also raised renewed concerns about the safety at the Zaporizhzhia nuclear power plant in southern Ukraine, which is under the control of Russian forces.

Ukraine told the IAEA on Monday that it had “lost control over” nuclear material at Zaporizhzhia and that data communication with the plant on nuclear safeguards had broken down. Nuclear safeguard mechanisms are essential to ensure that nuclear facilities are not misused and nuclear material is not diverted from peaceful uses, the agency said. Ukraine also said the supply chain for spare parts to the plant had been disrupted.

Grossi noted the concerns Monday in an address to the agency’s board of governors.

“I have repeatedly expressed my grave concern at the extremely stressful and challenging working conditions under which Ukrainian management and staff are operating the plant,” he said. “One clear line of Ukrainian operational control and responsibility is vital, not only for the safety and security of Zaporizhzhya NPP, but also so that IAEA inspectors are able to continue to fulfill their regular, indispensable verification activities.”

Ukrainian energy officials reacted angrily this week after Grossi said that he was working with Russian authorities to organize an emergency visit to the Zaporizhzhia facility.

Energoatom, Ukraine’s nuclear power plant operator, said in a statement that such a visit would only “legitimize the stay of the occupiers.”

There are eight operational nuclear reactors connected to the Ukrainian grid, including two at Zaporizhzhia, according to the agency.

Underscoring the danger posed by the Russian bombardment of Ukraine, the country informed international regulators Sunday that a cruise missile was observed flying above the plant.

“If a missile goes astray near a nuclear power plant, it could have a severe impact on its physical integrity, potentially leading to a nuclear accident,” Grossi said Wednesday.