The Chernobyl nuclear power plant and its security systems were shut down on Wednesday as fears began to grow that radioactive substances could be released from the site where the world's worst nuclear disaster occurred.

Ukraine's energy operator Ukrenerho said the plant "was fully disconnected from the power grid," adding that military operations meant "there is no possibility to restore the lines."

The International Atomic Energy Agency said that Ukraine had informed it of the power outage, but said that although the development "violates [a] key safety pillar," in this case it saw "no critical impact on safety." 

The site is currently being powered by generators instead, with electricity needed primarily for water cooling to control the heat of spent fuel at the site.

Shelling

On February 24, Russia invaded Ukraine and seized the defunct plant, where a 1986 disaster killed hundreds and spread radioactive contamination.

According to Ukrenerho, Chernobyl's power lines were damaged by shelling amid the ongoing conflict.

Ukrainian Foreign Minister Dmytro Kuleba said that Russia must urgently observe a temporary ceasefire to make repairs possible at the Chernobyl plant. He said that "reserve diesel generators have a 48-hour capacity to power" the site.

Both Germany and France are monitoring the situation closely, though a German environment ministry spokesperson said Berlin had no knowledge of radiation leaking from the Chernobyl nuclear plant.

"We are trying to clarify these reports together with the International Atomic Energy Agency," said French government spokesperson Gabriel Attal, who added that France was asking Russia to co-operate.

Seizure of Zaporizhzhia

Since the invasion began, Russian forces have seized control of the Zaporizhzhia plant in southern Ukraine.

According to Ukraine's energy ministry, Moscow's forces are forcing exhausted staff to record an address that they plan to use for propaganda purposes.

Russian troops have been in control of the Zaporizhzhia plant, Europe's largest, since seizing it last Friday. During the attack a building caught fire, raising fears of a nuclear disaster. It was later determined that no radiation was released.

jsi/msh (Reuters, dpa, AFP, AP)