What is the significance of the Zaporizhzhia nuclear power station?
The Zaporizhzhia* nuclear power station, with six reactors that began commercial operation between 1985 and 1996, is the largest nuclear power station in Europe in terms of net capacity. Each of its six Russia-designed VVER-320 reactors has a net capacity of 950 MW for a total of 5,700 MW (the second biggest is Gravelines in France with net capacity of 5,460 MW). State nuclear operator Energoatom says it can generate enough energy for roughly four million homes. In normal times it produces one-fifth of Ukraine’s electricity and almost half the energy generated by the country’s nuclear power facilities. The facility is in southeast Ukraine in Enerhodar on the banks of the Kakhovka reservoir on the Dnieper river. It is about 200km from the contested Donbas region and 550km southeast of the capital Kyiv.
The Zaporizhzhia nuclear station has been seized by Russian military forces, after a fire sparked by overnight shelling burned for several hours.
What has happened at Zaporizhzhia?
According to regional authorities Zaporizhzhia has been seized by Russian military forces, after a fire sparked by overnight shelling burned for several hours.
The Ukrainian state inspectorate for nuclear regulation SNRIU said in a statement on its Facebook page the plant had been “captured by the military forces of the Russian Federation”, but added that employees were continuing to work on the premises.
Energoatom said on the messaging and chat network Telegram at 07.33 local time that the administrative building and checkpoint at Zaporizhzhia were under Russian control. Staff continued daily work ensuring the stable operation of facilities. According to reports from Energoatom, there were three dead and two wounded among Ukrainian defending forces.
Ukraine told the International Atomic energy Agency that Zaporizhzhia had been shelled overnight. SNRIU said a fire at the site had not affected “essential” equipment and plant personnel were taking “mitigatory actions”. There was no reported change in radiation levels at the facility, it said. The IAEA said it was putting its Incident and Emergency Centre (IEC) in full response mode due to the situation. The fire broke out in a training building outside the station in the early hours of Friday, after being shelled by Russian forces, Ukrainian authorities said.
An employee at Zaporizhzhia posted on Telegram that Russian forces had fired on the facility and there was “a real threat of nuclear danger at the largest nuclear power plant in Europe”. Ukraine’s foreign minister confirmed the reports at 02.30, tweeting that the Russian army was “firing from all sides upon Zaporizhzhia NPP... fire has already broken out.” He called for an immediate ceasefire to allow firefighters to control the blaze. A short time later, the Ukrainian State Emergency Service reported that radiation at the plant was “within normal limits” and the fire conditions at the station were “normal”. They later reported that a third unit at the station was disconnected at 2.26am, leaving just one of the facility’s six units, number four, still operating.
What is the station’s status?
Of the six reactor units, Unit 1 is shut down for maintenance, Units 2 and 3 have undergone a controlled shut down, Unit 4 is operating at 60% power and Units 5 and 6 are being held “in reserve” in low power mode. The IAEA said the safety systems of the six reactors had not been affected and there has been no release of radioactive material. However, Energoatom has reported that the situation remains “very challenging” and therefore it has not yet been possible to access the whole site to assess that all safety systems are fully functional.
The fire, which has been extinguished, was in a training centre (circled in photo).
Is there a radiation threat?
Ukrainian authorities said at 11.00 on Friday that the facility was secured and “nuclear safety is now guaranteed”. Earlier, the IAEA said SNRIU told the agency that there was “no change reported in radiation levels at the Zaporizhzhia nuclear power plant site”. The US also said their latest information showed no indication of elevated radiation levels at the plant. The US energy secretary, Jennifer Granholm, said the reactors “are protected by robust containment structures and reactors are being safely shut down”.
What about Chernobyl?
Russia has already captured the shut-down Chernobyl nuclear station, 100km north of Kyiv. The Zaporizhzhia station is of a different and safer type to Chernobyl, which was the site of the world’s worst nuclear disaster in 1986. The IAEA said last week that Ukraine had informed the agency that “unidentified armed forces” had taken control of all facilities of the state-owned Chernobyl NPP enterprise, located within the exclusion zone. The facilities include the shut-down Units 1, 2, and 3, the destroyed Unit 4 and a two recently constructed spent nuclear fuel storage facilities.
SNRIU said an automated radiation monitoring system in the exclusion zone had shown gamma radiation doses exceeding control levels in parts of the exclusion zone. The regulator said its analysis attributed those readings to heavy military machinery movement in the area and subsequent disturbance of the radioactive residue, or dust, on the ground.
On Thursday, Ukraine asked the IAEA to appeal to Nato to close airspace over its nuclear facilities and to intensify actions to prevent what it called “acts of nuclear terrorism” over the seizure of the Chernobyl nuclear power station and exclusion zone.
The six nuclear plants at Zaporizhzhia are VVER-320 units. These “water-water energetic reactors” (WWER), or VVER units, are a series of pressurised water reactor designs originally developed in the Soviet Union, and now Russia, by OKB Gidropress. VVERs were originally developed before the 1970s, and have been continually updated. As a result, the name VVER is associated with a wide variety of reactor designs spanning from Generation I reactors to modern Generation III+ reactor designs. VVER power stations have mostly been installed in Russia and the former Soviet Union, but also in China, the Czech Republic, Finland, Germany, Hungary, Slovakia, Bulgaria, India, Iran and Ukraine. Units are under various stages of planning or construction in Finland, Hungary, Belarus, Bangladesh, Egypt, Turkey, India, Iran, and China.
The chances of explosion, nuclear meltdown or radioactive release are low, said Tony Irwin, an honorary associate professor at the Australian National University. Mr Irwin, who operated nuclear power plants in the UK for three decades, said the PWR reactors are “a lot safer” than the reactors at Chernobyl, and did not appear to be damaged yet. The reactors have large concrete contaminants and built-in fire protection systems, he said, adding: “Obviously, it’s not a good idea if you start shooting massive missiles at reactors,” he said. “The PWR [pressurised water reactor] type is a much safer sort of reactor, because it’s a two-circuit design reactor. The water that keeps the reactor cool is on a separate circuit to the second one, which actually supplies the power to the turbine and the outside.”
“These reactors have back-up emergency cooling systems as well. In addition to the normal reactor cooling, they’ve got a passive system, they’ve got high-pressure injection systems, they’ve got low-pressure injection systems.”
* For the sake of consistency NucNet has followed the naming and spelling conventions of the IAEA’s PRIS (Power Reactor Information System) database of commercial nuclear power plants, which uses the Russian spelling “Zaporozhye”. The Ukrainian spelling is “Zaporizhzhia”, which NucNet has now adopted, following its use in IAEA communications