More troubling NPP updates arrive from Ukraine

Staff at two nuclear power plants (NPP) in Ukraine that have been seized by Russian armed forces -- the operational Zaporizhzhia and the defunct Chernobyl -- have been dealing with more issues regarding power supply in recent days.

Chernobyl, which still runs radioactive waste management facilities at its site, has been disconnected from the electricity grid and lost its supply of external power, the International Atomic Energy Agency (IAEA) reported on Wednesday.

According to Rafael Mariano Grossi, director general of the IAEA, this would not have a critical impact on essential safety functions because the site has reserve emergency power supplies and there is a sufficient volume of cooling water to maintain effective heat removal from the spent fuel.

However, the regulator stressed that the lack of power could lead to a further deterioration of operational radiation safety there and would further complicate the situation for the roughly 210 technical experts and guards taking care of the site during Russia’s invasion of Ukraine. The staff has not been able to rotate for the past two weeks, the IAEA warned.

Russian armed forces captured the Chernobyl NPP in late February and eventually also seized the Zaporizhzhia NPP, which is the largest in all of Europe.

“I repeat my urgent appeal to the forces in effective control of the [Chernobyl] plant to respect internal radiation protection procedures, to facilitate the safe rotation of staff and to take other important steps to ensure safety,” director general Grossi added.

Meanwhile, the operator of the Zaporizhzhia NPP has informed the IAEA that two of the plant's four high voltage offsite power lines have been damaged. The facility now relies on the other two plus an additional one on standby. According to the operator, one power line is enough to cover the plant's off-site power needs. Back-up power can also be provided by diesel generators that are ready and functional.

At the same time, Zaporizhzhia's Unit 6 transformer is out of service and was undergoing emergency repair after its cooling system was damaged earlier this month.

The IAEA also expressed concern about the fact that in recent days it has lost remote data transmission from its safeguards systems installed to monitor nuclear material at both plants.

“Such systems are installed in several facilities in Ukraine, including all nuclear power plants, and enable us to monitor nuclear material and activities at these sites when our inspectors are not present,” Grossi explained. The data can still be stored locally but the storage capacity and the operational status of the monitoring systems are uncertain, he added.

As of Wednesday, eight of Ukraine’s 15 reactors were still operating, including two at the Zaporizhzhya NPP. Radiation levels at the sites were normal, the regulator noted.

Choose your newsletter by Renewables Now. Join for free!