In his latest update on the situation at the Zaporizhia NPP, IAEA  Director General Rafael Mariano Grossi said the plant had lost all external power for several hours, underlining the extremely precarious nuclear safety and security situation at the facility and the urgent need to protect it and prevent an accident.

It was the seventh time the plant had been completely disconnected from the national electricity grid since the military conflict in Ukraine began 15 months ago, forcing it to rely on emergency diesel generators for the power needed for reactor cooling and other essential nuclear safety and security functions.

Since Russia took control of ZNPP in March 2022, the Russian national guard has been protecting the station and in October, Russian President Vladimir Putin signed a decree formally transferring ZNPP to Russian jurisdiction under nuclear utility Rosenergoatom (part of Rosatom). A Russian Federal State Unitary Enterprise. Zaporizhia NPP was established by Rosenergoatom to operate the plant. However, Ukrainian nuclear utility Energoatom still claims ownership of the plant. Reports by Russian military analysts suggest that retaking control of ZNPP is one of the objectives of the coming Ukrainian offensive.

Grossi said ZNPP’s only remaining external 750 kilovolt (kV) power line was cut around 05:30am local time and re-connected after more than five hours, according to IAEA experts present at the plant. “This morning’s loss of all off-site power demonstrates the highly vulnerable nuclear safety and security situation at the Zaporozhia Nuclear Power Plant. As I’ve said repeatedly, this simply can’t go on. We’re playing with fire. We must act now to avoid the very real danger of a nuclear accident in Europe, with its associated consequences for the public and the environment,” he stressed.

“I’m continuing to engage in intense negotiations with all the involved parties to secure the protection of the Zaporizhia Nuclear Power Plant. I will not stop until this has been achieved,” he said.

He added that said he aimed to secure agreement on a set of principles to protect the ZNPP during the armed conflict, covering also the availability and security of external power supplies at all times. The seven indispensable pillars for nuclear safety and security outlined by the Director General early during the conflict also stress the need for secure off-site power supplies from the grid for nuclear sites.

The ZNPP does not have any operational back-up power lines since the last functioning 330 kV power line was damaged on the right bank of the Dnipro River on 1 March. This back-up power line has still not been repaired, meaning that when the 750 kV line is lost the plant immediately depends on its diesel generators which are its last line of defence for electricity supplies.

“For more than two and a half months, this major nuclear power plant has only had one functioning external power line. This is an unprecedented and uniquely risky situation. Defence-in-depth – which is fundamental to nuclear safety – has been severely undermined at the ZNPP,” Grossi said.

Director General Grossi called for stepped-up efforts to restore the ZNPP’s back-up power lines and reiterated the need for the IAEA team at the site to gain access to the nearby Zaporizhia Thermal Power Plant (ZTPP), which has yet to be granted despite assurances by Russian state nuclear company Rosatom. The ZTPP operates its 330 kV open switchyard, through which back-up power has in the past been provided to the ZNPP.

Initially after this morning’s off-site power cut, all the ZNPP’s 20 diesel generators started operating, but 12 of them were later switched off. This left eight running, which is sufficient to operate all systems safely. The IAEA experts at the site were informed that there is enough diesel fuel for 23 days. After the 750 kV line was restored, the diesel generators were gradually turned off.

Five of the ZNPP’s six reactors were already in a cold shutdown state before the latest power outage, and preparations were under way to transfer also unit 5 from hot to cold shutdown. However, following the restoration of off-site power, unit 5 is being returned to hot shutdown, IAEA said.

The ZNPP website confirmed the loss and restoration of power to the plant. It added: “The radiation background in the Zaporizhia NPP and in the sanitary protection zone does not exceed the values established by the norms and rules for radiation safety. In the area of the Zaporizhia NPP, the radiation situation corresponds to the natural background.” ZNPP Director Yuriy Chernichuk also confirmed that the power supply to the plant had been restored and “the station is operating normally”.

However, Vladimir Rogov, a member of the Main Council of the Zaporozhye regional administration alleged that the disconnection of the power line to ZNPP was a deliberate act by Ukraine. He said that electricity was supplied via this line from the right bank of the Dnieper River from the territory of the Dnipropetrovsk region, controlled by the Kiev regime. But there were no emergency situations that could lead to disconnection of the station. “This is deliberate sabotage,” he insisted.

According to a recent report in the Washington Post, Grossi “is now pushing for a new proposal to reduce the possibility of a catastrophic nuclear disaster” and “plans to present a list of five principles for the UN Security Council to endorse later this month.” The Post cited US and European diplomats as its sources.

“According to two diplomats familiar with the negotiations, Grossi’s plan includes five principles: a ban on stationing heavy military equipment and military personnel at the plant; a ban on firing from and toward the plant, including a ban on attacking the personnel at the site; protection of all safety and security systems at the plant; protection of all external power lines; and monitoring of compliance of the above-mentioned principles,” the paper said

The plan is less ambitious than Grossi’s original effort to establish a security and protection zone around the plant – which, though accepted by Russia, were rejected by Ukraine. A similar situation now seems to be arising. “Striking an agreement at the UN is likely to be difficult, but Grossi has already won the support of Moscow, according to a Russian diplomatic official briefed on the plan and who, like other officials, spoke on the condition of anonymity to discuss sensitive negotiations, “ the Post reported.

The paper cited a Russian diplomatic official as saying, “We have no objection against them,” noting that Moscow has been in touch with Grossi since last September. “We hope that the implementation of these principles will prevent any attack against ZNPP in the future,” the diplomatic official added. The Post added: “How Ukraine will respond to Grossi’s presentation at the UN – should it go forward – is less clear. A spokesman for [Ukrainian President Volodymyr] Zelensky did not respond to requests for comment.”

The Post continued: “Diplomats at the UN and analysts said that if Ukraine is planning to retake the plant in an upcoming counteroffensive, Grossi’s plan may be less appealing. ‘I could imagine that it might be more difficult for the Ukrainian side to accept, as it would prevent Ukraine from regaining control of the Zaporizhzhia plant by use of military force,’ [Scott] Roecker [a vice president at the Nuclear Threat Initiative] said.