The risks of the military attack were all the greater because one of the six reactors at Zaporizhzhia was operating at the time. Was Ukraine operating reactors because the electricity they produced was absolutely essential?
Was the Ukrainian government hoping that continuing to operate reactors would minimise the risk of a military attack on the nuclear plant? How will the lessons learned from the Zaporizhzhia experience play out at the other three nuclear power plants?
Zaporizhzhia staff are currently operating the nuclear plant under Russian control: any action, including measures related to the technical operation of the reactors, requires approval from the Russian commander.
The International Atomic Energy Agency (IAEA) reported on March 9 that the Zaporizhzhia site has four high-voltage (750 kV) offsite power lines plus an additional one on standby, but that it had been informed by the Ukrainian operator that two lines have been damaged and thus there are now two operating lines plus one on standby. The operator said that power requirements could be maintained with one line.
If grid power is lost, the adequacy of backup power generators to maintain essential cooling of reactors and spent fuel will depend on factors such as the integrity of the diesel fuel store, and the viability of securing further diesel fuel. The inability to run generators was one of the causes of the Fukushima disaster.
Moreover, SNRIU said that its nuclear safety inspectors are not allowed to access the Zaporizhzhia plant due to the Russian troops deployed in the area.
Added to this, SNRIU said that phone lines, email and fax were not functioning at Zaporizhzhia, with only some poor quality mobile phone service possible, so “reliable information from the site cannot be obtained through normal channels of communication”.
The IAEA said on March 11: “It was not currently possible to deliver necessary spare parts, equipment and specialised personnel to the site to carry out planned repairs, and maintenance activities at Unit 1 had been reduced to the minimum level required by the plant operational procedures.”
No reactors have operated at the Chernobyl site since the year 2000 but the site still has a large quantity of spent nuclear fuel, as well as the radioactive mess left by the 1986 disaster in reactor #4.
The Russian military took control of the Chernobyl site on February 24. Radiation levels were elevated due to heavy military equipment disturbing the contaminated dust around the site.
Russian occupiers have kept around 210 plant operators and guards at the Chernobyl site since February 24 without a new shift to relieve them.
A relative of one worker told the BBC that the Russian military was willing to let them swap shifts, but that they could not guarantee their safety on the journey home, nor of workers travelling to take their place.
According to the Ukrainian government, workers are being subjected “to psychological pressure and moral exhaustion” with “limited opportunities to communicate, move, and carry out full-fledged maintenance and repair work.”
The European Nuclear Safety Regulators Group warned on March 6 about the “current fragility of the electrical supplies to the site, with only one supply line out of three available and back-up diesel power having sufficient fuel supplies for only 48 hours”.
The situation worsened with the loss of power from a 750 kV high-voltage line to the area on March 9, thus disconnecting the site entirely from the grid. On-site emergency diesel generators were activated “to power systems important to safety”.
Energoatom said a loss of power made “it impossible to control the nuclear and radiation safety parameters at the facilities”, adding that repairs to restore the area’s power supply could not happen at the moment because of “combat operations in the region”.
Whether the spent fuel at Chernobyl is at risk due to the loss of power is debated. Energoatom said there are about 20,000 spent fuel assemblies at Chernobyl that could not be kept cool during a power outage and warned of the release of radioactive substances into the environment.
The IAEA is less concerned, saying that it saw “no critical impact on safety” due to the low heat load and the volume of cooling water.
The IAEA said on March 10: “If emergency power was also to be lost, the regulator said it would still be possible for staff to monitor the water level and temperature of the spent fuel pool. But they would carry out this work under worsening radiation safety conditions due to a lack of ventilation at the facility. They would also not be able to follow operational radiation safety procedures.”
Ukraine’s Foreign Minister Dmytro Kuleba said that Russia must observe a temporary ceasefire to enable repairs at the Chernobyl plant. Reports on March 11 indicate that off-site power may have been restored to the Chernobyl site ‒ the IAEA is seeking confirmation.
Russian missiles hit a radioactive waste storage site near Kyiv on February 27.
The IAEA said in a March 1 update: “SNRIU said that all radioactive waste disposal facilities of the State Specialized Enterprise Radon were operating as usual, and the radiation monitoring systems did not indicate any deviations from normal values.
“On 27 February, the SNRIU informed the IAEA that missiles had hit the site of such a facility in the capital Kyiv, but there was no damage to the building and no reports of a radioactive release.”
The Kyiv radioactive waste storage site appears to be at least 1 km from any other human structures, suggesting the possibility of a deliberate strike.
Also on February 27, an electrical transformer was damaged at a radioactive waste storage site in Kharkiv, also without any reports of a radioactive release. According to SNRIU, a research reactor at the site has been shut down.
The Kyiv and Kharkiv facilities typically hold disused radioactive sources and other low-level waste from hospitals and industry, the IAEA said, but do not contain high-level nuclear waste. However the Kharkiv site may also store spent nuclear fuel from the research reactor.
An Oncology Center in Kharkiv was destroyed by Russian shelling, jeopardising the safety and security of high-level radiation sources.
SNRIU said on March 6 that there continued to be no communication with enterprises and institutions using Category 1-3 radiation sources in the eastern port city of Mariupol, including its Oncology Center, and that the safety and security of the radiation sources could not be confirmed. Such material can cause serious harm to people if not secured and managed properly, the IAEA noted.
SNRIU reported that a ‘Neutron Source‘ ‒ a subcritical assembly with 37 nuclear fuel elements, controlled by a linear electron accelerator ‒ at Kharkiv’s Institute of Physics and Technology was subjected to artillery fire on March 6.
The European Nuclear Safety Regulators Group said in a March 6 statement that it is “very concerned about the safety of several research reactors as well as sites holding highly radioactive sources.”