Ukraine: Russia-Ukraine War and Nuclear Energy

(Updated 25 November 2022)

  • In February 2022, Russia launched a military offensive against Ukraine.
  • On 24 February Ukraine informed the IAEA that Russian forces had taken control of all facilities of the Chernobyl nuclear power plant. Control of the site was returned to Ukrainian personnel on 31 March.
  • In the early hours of 4 March the Zaporizhzhia plant in southeastern Ukraine became the first operating civil nuclear power plant to come under armed attack. Fighting between forces overnight resulted in a projectile hitting a training building within the site of the six-unit plant. Russian forces then took control of the plant. The six reactors were not affected and there was no release of radioactive material.
  • Since late October, Russia has repeatedly targeted Ukraine's civilian infrastructure, including the country's energy system, with missile strikes. Widespread blackouts have resulted, and external power supply to all four of the country's nuclear plants has been affected.

The International Atomic Energy Agency (IAEA) is closely monitoring developments in the country with respect to its nuclear facilities and is providing regular updates on the situation.

Timeline – key events

24 February

Ukraine disconnected its grid from Belarus and Russia, and requested emergency synchronization to the European power grid.

Ukraine informed the IAEA that Russian forces had taken control of all facilities of the Chernobyl nuclear plant. 

2 March

Russia informed the IAEA that its military forces had taken control of the territory around Ukraine’s Zaporizhzhia nuclear plant. It said that radiation levels remained normal and added that personnel at the plant continued their “work on providing nuclear safety and monitoring radiation in normal mode of operation."

3 March

The State Nuclear Regulatory Inspectorate of Ukraine (SNRIU) reported that a large number of Russian tanks and infantry “broke through the block-post" to the town of Enerhodar, a few kilometres from the Zaporizhzhia nuclear plant. Power from one of the two offsite power transmission lines supplying electricity to the site was lost overnight. The power line does not provide power to safety-related equipment, but the loss of power created difficulties in carrying out routine maintenance and repair of some equipment. In an urgent letter to IAEA Director General Rafael Mariano Grossi, the SNRIU said: “The battle is going on in the town of Enerhodar and on the road” to the Zaporizhzhia nuclear plant. Grossi called for a halt to the use of force and called upon military forces to refrain from violence near the nuclear power plant.

4 March

Fighting between forces overnight resulted in a projectile hitting a training building within the site of the six-unit Zaporizhzhia plant. The SNRIU said a resulting fire at the site had not affected "essential" equipment and that plant personnel were taking mitigatory actions. There was no reported change in radiation levels at the plant and the six reactors were not affected. Russian forces took control of the plant. Energoatom informed the IAEA that the plant had been allowed to change work shifts.

5 March

The SNRIU reported to the IAEA that staff at the Chernobyl nuclear plant has been onsite since 23 February without being able to rotate shifts for either technical personnel or guards.

6 March

The SNRIU reported that staff at the Zaporizhzhia plant were now under orders from the commander of the Russian forces that took control of the site on 4 March. The regulator also said that Russian forces had switched off some mobile networks and the internet, preventing the communication of information from the site via normal channels.

9 March

The Chernobyl nuclear plant was disconnected from the electricity grid. The IAEA stated that it did not see a critical impact on safety as a result.

13 March

On 13 March Energoatom reported that transmission system operator Ukrenergo had at 18.38 succeeded in repairing a power line needed to restore external electricity supplies to Chernobyl.

14 March

At 16.45 local time the Chernobyl nuclear plant was reconnected to the national grid.

16 March

Ukraine and Moldova's electricity networks were connected to the continental European grid on a trial basis.

20 March

The SNRIU confirmed that around half of the staff at Chernobyl nuclear plant had been able to rotate and return to their homes for the first time since 23 February.

29 March

IAEA Director General Rafael Mariano Grossi entered Ukraine to provide technical assistance to ensure the safety and security of the country's nuclear facilities.

31 March

Energoatom said that Russian forces had left the Chernobyl site and nearby town of Slavutych.

7 April

In response to reported atrocities committed by the Russian armed forces, the European Parliament voted in favour (513 for; 22 against; 19 abstentions) of a resolution calling for a number of punitive measures against Russia, including “an immediate full embargo on Russian imports of oil, coal, nuclear fuel and gas”.

26 April

IAEA Director General Rafael Mariano Grossi arrived in Ukraine with experts from the agency to "conduct nuclear safety, security and radiological assessments, deliver vital equipment and repair the Agency's remote safeguards monitoring systems" at the Chernobyl site.

22 July

Ukrainian military launched drone strikes on Russian forces stationed at the Zaporizhzhia nuclear plant.

5 August

Shelling reportedly damaged the Zaporizhzhia plant's external power supply system, triggering the emergency protection system of one of the three reactors (unit 4) operating at the time.

6 August 

Shelling reportedly injured a Ukrainian security guard and damaged "walls, a roof and windows" in the area of the Zaporizhzhia plant's spent fuel storage facility.

25 August

Damage to an offsite power supply line forced operators at Zaporizhzhia to disconnect the plant's two operating units from the country's electrical grid. Offsite power supply was restored later the same day.

1 September

A team of inspectors from the IAEA arrived at the Zaporizhzhia plant. The IAEA assessed the physical damage to facilities, determined the functionality of the main and back-up safety and security systems, evaluated the working conditions of the control room staff, and undertook safeguards activities. IAEA Director General Rafael Mariano Grossi said that it was "obvious that the plant and the physical integrity of the plant has been violated several times." The IAEA planned to keep a permanent presence of two staff at the plant.

21 September

At 1:13 am, renewed shelling at the Zaporizhzhia plant damaged cables providing electricity to one of its six reactors. Unit 6 had to rely on two of the three emergency diesel generators for 40 minutes to ensure essential safety functions.

1 October

Ihor Murashov, Director General of the Zaporizhzhia plant, was detained by Russian forces. On 4 October the IAEA said it had been informed that Murashov would not be returning to his role at the plant.

5 October

Russian President Vladimir Putin issued a decree to transfer the Zaporizhzhia plant to Russian control. Ukraine described the decree as "null and void".

6 October

Renewed shelling damaged a 150 kV power line providing electricity via the switchyard of a nearby thermal power station to Zaporizhzhia unit 6. Five emergency diesel generators started supplying back-up power to the unit. The generators operated for about an hour and a half, before an alternative source of power from four of the other reactors was connected.

8 October

The Zaporizhzhia plant lost access to external power following shelling. The plant's emergency diesel generators provided cooling and other essential nuclear safety and security processes. External power was restored on 9 October.

12 October

The Zaporizhzhia plant lost external power for a few hours following damage to a substation located far from the plant itself.

3 November

The South Ukraine plant lost connection to one of its three 750 kV power lines used to supply electricity to the grid.

15 November

The Khmelnitski plant lost connection to the grid and the Rivne plant lost connection to one of its 750 kV power lines following Russian missile strikes on Ukraine's energy infrastructure. Neighbouring Moldova experienced blackouts as a result of the strikes.

19 & 20 November

Shelling at the Zaporizhzhia plant damaged buildings, systems and some equipment.

23 November

All units at Rivne, South Ukraine and Khmelnitski were automatically disconnected from Ukraine's grid following a decrease in frequency resulting from Russian missile strikes on Ukraine's energy infrastructure. Neighbouring Moldova experienced blackouts as a result of the strikes.

Nuclear power plants overview

Ukraine has 15 operable nuclear reactors at four plants that generate about half of its electricity. All reactors are Russian VVER types, two being upgraded 440 MWe V-312 models and the rest the larger 1000 MWe units – two early models and the rest V-320s.

As of 25 November, three of the country's four plants were providing electricity to Ukraine's grid: Khmelnitski, Rivne and South Ukraine. 

For more information on the country’s nuclear energy industry, see information page on Nuclear Power in Ukraine.

Location of Ukraine's operable and shut down nuclear power plants

Zaporizhzhia nuclear power plant

Reactor status (as of 25 November): units 1-4 – cold shutdown; units 5&6 – semi-hot shutdown.

In the early hours of 4 March 2022, the plant became the first operating civil nuclear power plant to come under armed attack. A projectile hit a training building located approximately 300 metres from unit 1 of the plant (see image below). SNRIU stated that the resulting fire was extinguished at 06:20 local time on 4 March. The IAEA said that the fire at the site had not affected "essential equipment". Just one of the six reactors (unit 4) at the plant was producing electricity at the time of the attack. The statuses of unit 1 (maintenance outage) and units 5&6 (held in reserve, operating in low power mode) were initially unchanged as a result of the attack, whilst units 2&3 underwent a controlled shutdown. However, on 9 March Energoatom reported that unit 6 had been put in "emergency repair" on 7 March as a result of damage sustained to the block transformer during fighting in the early hours of 4 March.

Fire at Zaporizhzhia nuclear plant caused by Russian projectile

Image 1: Fire at the training centre within the site of the Zaporizhzhia nuclear plant after fighting in the early hours of 4 March (Photo: Energoatom via AP)

On 5 March the SNRIU confirmed that the technical safety systems were intact and radiation levels remained normal. It reported that one telephone communication line had been lost but another was still functioning, as well as mobile phone communication. The IAEA was informed that the training centre hit by a projectile in the early hours of 4 March had suffered significant damage, and that there had also been damage to the site's laboratory building and to an administrative structure. A visual inspection of the dry storage facility did not detect any damage.

On 6 March the SNRIU said that staff at the Zaporizhzhia plant were now rotating in three shifts, but were under orders from the commander of the Russian forces that took control of the site on 4 March. According to the regulator, any action of plant management, including measures related to the technical operation of the plant, requires prior approval from the commander. The regulator also said that Russian forces had switched off some mobile networks and the internet, preventing the communication of information from the site via normal channels.

On 9 March the SNRIU informed the IAEA that two of the plant's five high-voltage off-site power lines had been damaged and so were inoperable. Energoatom said that the plant's offsite power needs could be provided with just one power line. The IAEA said that remote data transmission from safeguards monitoring systems installed at the facility had been lost.

On 11 March the SNRIU said that staff at the plant were rotating according to their usual schedule and without interference in their day-to-day activities. The IAEA reported that remote data transmission from safeguards systems at the plant was back online, having been lost on 9 March.

On 14 March Energoatom said that Russian forces had carried out munition explosions at the site. The SNRIU had previously informed the IAEA about work to detect and dispose of any unexploded munitions following the events on 4 March when Russian forces took control of the site.

On 16 March the SNRIU said that the Zaporizhzhia plant had lost connection to a third power line, leaving two available. The regulator has said that a single power line is sufficient to provide power for all safety systems.

On 17 March a break in an onsite power line prompted the operators of the plant to temporarily reduce the output of the two operating reactors slightly from 600 MWe to 500 MWe each. The onsite line was fixed later on the same day and power levels were increased.

On 19 March the SNRIU said that one of the three disconnected offsite power lines had been restored. The repair of the line means that the site now has three offsite power lines available, including one held in reserve.

On 27 March the SNRIU said that repair work to the transformer of unit 6, which was damaged during the events of 4 March, had been completed.

In its report released on 28 April, the IAEA said that "about ten" Rosatom staff members were present at the Zaporizhzhia plant and that it "considers the presence of Rosatom senior technical staff could lead to interference with the normal lines of operational command or authority, and potential frictions when it comes to decision-making."

On 30 May the automatic transfer of safeguards data to the IAEA from systems installed at the Zaporizhzhia plant stopped. The IAEA said on 12 June that transmission of the data had restarted. It was lost again on 25 June before being restored on 4 July.

On 22 July Ukraine's military intelligence service released footage of a drone strike on Russian forces at the Zaporizhzhia plant.

On 3 August Grossi said the IAEA had limited communication with the workers at the plant and reiterated the need for the IAEA to travel to Ukraine to inspect the plant.

On 5 August shelling reportedly damaged one of the plant's external power supply lines. Ukraine informed the IAEA on 6 August that there had been no damage to the reactors themselves, no radiological release and no reports of injuries, and that two external power lines remained operational. Damage was reported to an auxiliary system, specifically a nitrogen-oxygen station, and an unspecified auxiliary building.

On 6 August shelling reportedly damaged "walls, a roof and windows" in the area of the plant's spent fuel storage facility and injured a Ukrainian security guard.

On 7 August Energoatom said that a worker at the plant had been wounded during the shelling on 5 August.

Further shelling was reported to the IAEA by Ukraine on 11 August. Ukraine said the shelling had caused damage to radiation monitoring equipment at the plant's fire station.

On 23 August Ukraine reported to the IAEA that further shelling on 20 and 21 August had damaged laboratory and chemical facilities in the vicinity of the nuclear plant, and damaged transformers of the non-nuclear thermal plant that is situated about 3.5km east of the nuclear reactors. The damage to the non-nuclear plant caused a disconnection of the power line linking it to the nuclear plant that lasted for several hours.

On 25 August Ukraine informed the IAEA that the plant lost connection to its last remaining operational external power line. As a result, the two reactors (units 5&6) that were operating at the plant were disconnected from Ukraine's electricity grid. The power line connection was restored later on 25 August, and reactors 5&6 were reconnected to the grid on 26 August.

The power needs of the six-unit plant are normally served by four 750 kV external power lines connected to Ukraine's grid, with three 330 kV lines, connected to a nearby thermal power plant, providing back-up. For more information on the plant's external and back-up power supplies, see below.

On 1 September a team of inspectors from the IAEA arrived at the Zaporizhzhia plant following months of negotiations. The IAEA visited the site to assess the physical damage to facilities at the plant, determine the functionality of the main and back-up safety and security systems, evaluate the working conditions of the control room staff, and undertake safeguards activities. IAEA Director General Rafael Mariano Grossi said that it was "obvious that the plant and the physical integrity of the plant has been violated several times." The IAEA planned to keep a permanent presence of two staff at the plant.

On 3 September the plant once again lost connection to its last operational 750 kV power line following further shelling in the area. The IAEA said that one of the three 330 kV reserve lines was delivering the electricity generated by the Zaporizhzhia plant to the grid – and that the same line can provide back-up power to the plant if needed. Ukraine said the 750 kV line would be repaired but that it would take several days to do so.

On 5 September the 330 kV reserve line being used was deliberately disconnected due to having to extinguish a fire. The line itself was not damaged, and electricity generated at unit 6 in low power mode was used to provide the plant with its safety and security needs. Ukraine said that the 330 kV line would be reconnected once the fire has been extinguished.

On 6 September the IAEA published its report3 on the situation at Zaporizhzhia following its visit to the site. The IAEA reported damage to the following caused by the events since March:

  • One turbine lubrication oil tank.
  • The roofs of various buildings such as the building for the spent fuel transporter vehicle.
  • The special building that houses, among other items, the fresh nuclear fuel and the solid radioactive waste storage facility.
  • The new training building.
  • The building where the central alarm station of the physical protection system is located.
  • The container where the radiation monitoring system is located, in the vicinity of the dry spent fuel storage facility.

The IAEA noted: "The presence of Russian military personnel, vehicles and equipment at various places [at the plant] including several military trucks on the ground floor of the unit 1 and unit 2 turbine halls and military vehicles stationed under the overpass connecting the reactor units."

Following its visit the IAEA called for the "immediate establishment of a nuclear safety and security protection zone."

Grossi inspects shelling damage at Zaporizhzhia nuclear plant

Image 2: IAEA director general Grossi inspects shelling damage during his visit to the plant (Source: IAEA)

Further shelling on 7 September damaged one of the three 330 kV reserve lines, and then the thermal power plant's switchyard on 8 September, causing a complete power blackout in the local city of Enerhodar.

On 10 September the damaged 330 kV reserve line was restored, and connection re-established, providing the nuclear plant with the electricity it needs for safety and security functions directly from the grid. Following restoration of this line, unit 6, which had been operating in low power mode to provide the plant with its electricity needs, was shut down.

On 21 September shelling damaged cables providing electricity to unit 6 at the plant. Two of the unit's three emergency diesel generators provided power to the unit for about 40 minutes whilst access to external electricity supplies were re-established.

In the week commencing 26 September a number of landmines exploded near the plant, likely caused by the movement of wildlife in the local area. On 27 September the IAEA said that explosions had broken windows in the turbine hall of unit 2. On 30 September the Agency said that an explosion had damaged a 6 kV cable just outside the plant's perimeter fence. Due to a short-circuit of the damaged cable, the explosion indirectly damaged a voltage transformer at unit 6, resulting in smoke at the site.

On 1 October Ihor Murashov, Director General of the Zaporizhzhia plant, was detained by Russian forces. On 4 October the IAEA said it had been informed that Murashov would not be returning to his role at the plant. The IAEA said it was not yet clear who would replace him.

On 5 October Russian President Vladimir Putin issued a decree to transfer the Zaporizhzhia plant to Russian control and oversight. The decree said that a new company, the Operating Organisation of Zaporizhzhia NPP, has been created with the "status of a nuclear energy operating organisation to operate and/or discontinue the operation of nuclear power facilities at the Zaporozhye Nuclear Power Plant." Rosatom in a statement on its website said that the new company would be headed by Oleg Romanenko, who was previously chief engineer of the Balakovo nuclear power plant. Ukraine's Ministry of Foreign Affairs described the statement as an "illegal attempt" to transfer operational control of the plant and said it was the latest in "a long line of crimes and violations of international law committed by Russia." It added that it considered the decree to be "null and void".

Also on 5 October the IAEA said that its experts had learned that unit 5 was planned to be restarted at reduced power to produce steam and heat for the plant.

On 8 October the plant lost access to external power after shelling damaged the last operating 750 kV power line. Emergency diesel generators provided cooling and other essential nuclear safety and security processes. In response, IAEA Director General Rafael Mariano Grossi described the renewed shelling as "tremendously irresponsible" and emphasized the need for a "nuclear safety and security protection zone around the plant." External power was restored on 9 October.

On 12 October external power was lost again for a few hours following damage to a substation located far from the plant itself.

On 14 October one of three backup power lines connecting the Zaporizhzhia plant to a thermal power plant 3.5 km east of the reactors was restored. This line can be used to provide external power if required.

On 18 October connection to the plant's last operating 750 kV power line was restored.

On 27 October the IAEA reported that the Zaporizhzhia plant had over the past ten days been receiving power from the national grid without interruption. It also said that a second backup power line connecting the plant to a nearby thermal plant had been restored in recent days.

Also on 27 October the IAEA highlighted changes to the operational command at the facility since Russia's decree on 5 October. It said that the number of Russian technical staff at the site had increased and that they were now involved in "taking significant operational decisions". For example, Ukrainian operating staff had planned to restart unit 5, but it currently remains in a hot shutdown mode as Russian officials have not agreed to start it up again.

On 3 November the plant lost connection to its 750 kV power line. Hours later it also lost connection to its 330kV reserve line. Ukrainian operating staff said that damage to the lines had been sustained about 50-60 kilometres from the plant itself. External power was restored on 5 November. On 19 and 20 November repeated shelling at the Zaporizhzhia plant resulted in damage to "buildings, systems and equipment" according to IAEA. Site management reported damage to a radioactive waste and storage building, cooling pond sprinkler systems, an electrical cable to one of the diesel generators, condensate storage tanks, and to a bridge between a reactor and its auxiliary buildings. The plant's external power supplies were not impacted. 


Image 3: location of reactors, spent fuel storage facility, and key events on 4 March and 22 July
Blue square and numbered – the six units of the Zaporizhzhia nuclear power plant
Red square – location of the training centre hit by a projectile on 4 March
Yellow arrow – approximate location and direction of Image 1
Orange square – location of the dry storage facility for used fuel
Green square – location of Ukrainian drone strike 22 July
Purple square – area of shell impacts recorded by the IAEA on its visit to site
Sources: Google, IAEA, Defence Intelligence of Ukraine

The reactors at the six-unit Zaporizhzhia nuclear power plant are Russian-designed VVER-1000 (V-320) units commissioned between 1984 and 1995. The V-320 has a full-pressure single containment, which has the shape of a hollow cylinder with a spherical dome and a flat bottom. The reinforced concrete wall of the containment is 1.2m thick in its cylinder-shaped section and 1.1m thick in its dome section. There is an 8mm steel liner on the internal side of the containment.

Spent fuel assemblies removed from each reactor at Zaporizhzhia are initially stored for several years in racks in spent fuel pools inside the reactor containment. Once sufficiently cooled, fuel assemblies are transferred to a dry spent fuel storage facility situated at the site. At Zaporizhzhia, the dry storage facility is protected along its perimeter by a concrete wall 30cm thick and 6m high. The spent fuel stored at the dry storage facility is in concrete containers.

External and back-up power supply

Zaporizhzhia has four main high voltage (750 kV) offsite power lines. Three 330 kV back-up lines, connected to a thermal power plant 3.5 km east of the reactors, remain on standby during normal operation, but can be used to deliver the electricity generated at Zaporizhzhia to the grid, and to provide back-up power for the plant. In the event of complete loss of offsite power, each reactor has three back-up diesel generators. One generator is sufficient to maintain a reactor and its spent fuel in a safe state for ten days. A further two 'bunkerized' diesel generators are present onsite. Each unit at the plant is equipped with one mobile diesel generator, which could be used to provide power to any of the other units if needed.1

Nuclear power plants require back-up electricity supplies to provide cooling for the removal of decay heat produced by shutdown reactors, and to maintain services (e.g. systems control, lighting, communication, ventilation) to the site.

Geneva Conventions

The Additional Protocol of 1979 to the Geneva Conventions contains in Article 56 a provision stating that nuclear power plants “shall not be made the object of attack, even where these objects are military objectives, if such an attack may cause the release of dangerous forces and consequent severe losses among the civilian population."

Emergency preparedness

In September 2017, the State Emergency Service of Ukraine in cooperation with the Defence Threat Reduction Agency of the United States Department of Defense and the Federal Emergency Management Agency of the USA conducted an emergency response exercise related to a radiation accident at the Zaporizhzhia nuclear power plant. One of the main tasks of this training was to improve plans and procedures to protect the public against natural, man-made, social and military threats. Further exercises were carried out with support of the US Department of Defense in 2018 to check the effectiveness of the facility's plans in the event of sabotage and anti-terrorism activity.2

South Ukraine nuclear power plant

On 16 April the SNRIU informed the IAEA that onsite video surveillance had recorded a missile flying directly over the South Ukraine nuclear plant. The IAEA said it was "looking into this matter, which, if confirmed, would be extremely serious."

On 5 June Energoatom said it had recorded a Russian missile flying "critically low" over the South Ukraine nuclear plant.

On 20 September Energoatom reported that a Russian missile landed 300 metres away from the reactors at the South Ukraine nuclear plant (also known as Pivdennoukrainsk Nuclear Power Plant, PNPP), causing damage to the plant. Energoatom stated: "All three power units of the PNPP are operating normally [with] no casualties among the station staff."

On 3 November the South Ukraine plant lost connection to one of its three 750 kV power lines used to supply electricity to the grid. As a result the plant reduced the power of one of its three operating reactors by 50%.

On 23 November Russian missile attacks on Ukrainian energy infrastructure caused widespread blackouts across the country. A resulting drop in grid frequency caused reactors at the South Ukraine plant to automatically disconnect from the grid. The reactors were reconnected to the grid and were operating by 25 November. 

Khmelnitski nuclear power plant

On 15 November the Khmelnitski nuclear plant lost all access to Ukraine's electricity grid. The plant's four operating power lines were progressively lost over a two-and-a-half-hour period as a result of Russian missile strikes on Ukraine's energy infrastructure. As a result of the strikes the two reactors were shut down and diesel generators provided required cooling. Offsite power was reestablished nine hours later through two 330 kV backup power lines, allowing the diesel generators to be turned off.

On 23 November Russian missile attacks on Ukrainian energy infrastructure caused widespread blackouts across the country. A resulting drop in grid frequency caused reactors at the Khmelnitski plant to automatically disconnect from the grid. The reactors were reconnected to the grid and were operating by 25 November.

Rivne nuclear power plant

On 15 November connection to one of two 750 kV power lines linking Rivne nuclear plant to Ukraine's electricity grid was lost. As a result the plant reduced its power output, and one of its four units was automatically disconnected from the grid.

On 23 November Russian missile attacks on Ukrainian energy infrastructure caused widespread blackouts across the country. A resulting drop in grid frequency caused reactors at the Rivne plant to automatically disconnect from the grid. The reactors were reconnected to the grid and were operating by 25 November.

Chernobyl

On 24 February 2022, Russian forces took control of all facilities of the Chernobyl nuclear plant. Control levels of gamma radiation dose rates in the Chernobyl exclusion zone were exceeded. The SNRIU said that the rise in radiation levels was likely due to “disturbance of the top layer of soil from movement of a large number of heavy military machinery through the exclusion zone and increase of air pollution.” It added: “The condition of Chernobyl nuclear facilities and other facilities is unchanged." Radiation readings from the site were assessed by the IAEA to be low and in line with near background levels.

On 2 March the SNRIU said it maintained communications with the site and that the site's personnel were carrying out their duties under "supervision".

On 5 March the SNRIU said that staff at the Chernobyl plant had been onsite since 23 February. As of 7 March the SNRIU said that there had still not been a rotation of technical personnel or guards since the Russian forces took control of the site.

On 8 March the SNRIU said that the handling of nuclear material at Chernobyl had been put on hold. It added that it could only communicate with the plant via email. The IAEA said that remote data transmission from safeguards monitoring systems installed at Chernobyl had been lost.

On 9 March at 11.22 local time the Chernobyl plant lost connection to the grid. The SNRIU said that back-up diesel generators were running and had 48 hours of fuel. The IAEA stated that, based on the heat load of spent fuel in the ISF-1 storage pool, and the volume of cooling water it contained, there would be sufficient heat removal without electrical supply. It said that it saw no critical impact on safety as a result of the loss of power, but said that the loss of power would likely create additional stress for the about 210 staff who have not been able to rotate for the past two weeks.

Professor Geraldine Thomas, director of the Chernobyl Tissue Bank, said: "They [the used fuel bundles] will not be producing significant amounts of heat, making a release of radiation very unlikely. In the unlikely event of a release of any radiation, this would be only to the immediate local area, and therefore not pose any threat to western Europe – there would be no radioactive cloud."

On 10 March the SNRIU told the IAEA that it had lost all communications with the Chernobyl nuclear plant. Prior to the loss of communication, the regulator had been able to confirm that the structures and systems of the ISF-1 used fuel storage pool had sustained no damage. The IAEA reiterated on 10 March that the loss of offsite power will not have a critical impact on essential safety systems. If emergency power to the site is also lost, the regulator said that staff would still be able to monitor the water levels and temperature of the spent fuel pool, albeit under "worsening radiation safety conditions" due to a lack of ventilation at the facility.

On 11 March the SNRIU said that technicians had started work on the evening of 10 March to repair damaged power lines to restore external electricity supplies. Emergency diesel generators continued to provide power to the site and additional fuel had been delivered.

European stress tests in 2011 included power loss scenarios at Chernobyl. The tests concluded that in the event of a loss of offsite power and back-up power, the water temperature in spent fuel pools would “increase but not exceed 70°C”.

On 13 March Energoatom reported that transmission system operator Ukrenergo had at 18.38 succeeded in repairing a power line needed to restore external electricity supplies to Chernobyl. However, Ukrenergo reported in the morning of 14 March that the line had sustained further damage "by the occupying forces". Later on 14 March Ukrenergo said that external power had been restored at 13.10 local time, and at 16.45 the plant was reconnected to Ukraine's electricity grid.

On 23 March the SNRIU reported that firefighters were trying to extinguish wildfires near the Chernobyl site. Seasonal wildfires often occur within the Chernobyl exclusion zone. The regulator and the IAEA assessed the radiological risk as low based on years of experience of such fires and on the amount of residual radioactive contamination in the soil.

On 24 March the State Agency for the Management of the Exclusion Zone said that an environmental laboratory had been "looted by marauders". The IAEA said that the incident did not pose a significant radiological risk.

On 30 March reports emerged of Russian forces receiving high doses of radiation whilst being in the Chernobyl exclusion zone. The IAEA said it had been unable to confirm the validity of these reports and that it was seeking further information to provide an independent assessment. 

On 31 March the SNRIU told the IAEA that the Russian forces that had been in control of the Chernobyl plant since 24 February had, in writing, transferred control of the plant to Ukrainian personnel. Ukraine's defence ministry confirmed on 1 April that Russian forces had fully withdrawn from the Chernobyl plant.

On 19 April SNRIU informed IAEA that direct communications between it and the Chernobyl plant had been restored. Contact had been lost more than one month earlier during the period when Russian forces controlled the site.

From 25 to 28 April IAEA Director General Grossi led an IAEA mission to the Chernobyl site to "conduct nuclear safety, security and radiological assessments, deliver vital equipment and repair the Agency's remote safeguards monitoring systems." As part of the mission, IAEA technicians upgraded the remote radiation monitoring systems installed at the site and deployed new satellite transmission channels. Remote data transmission had been disrupted since the Russian forces took control of the site in February, but was restored on 11 May. A second mission was sent by the IAEA to the Chernobyl site between 31 May and 3 June.

The Chernobyl plant was the site of a major nuclear accident in 1986. It was the product of a flawed Soviet reactor design coupled with serious mistakes made by the plant operators. It was a direct consequence of Cold War isolation and the resulting lack of any safety culture. The accident destroyed the Chernobyl 4 reactor. Chernobyl unit 4 was enclosed in a large concrete shelter which was erected quickly (by October 1986) to allow continuing operation of the other reactors at the plant. This structure was neither strong nor durable and was replaced by a new safe confinement structure in 2017. Units 2, 1 and 3 were shutdown in 1991, 1996 and 2000 respectively. There are no operating reactors at the site. For more information about the accident at Chernobyl, see information page on Chernobyl Accident 1986.

There are two fuel storage facilities at the Chernobyl plant. A wet storage pool (ISF-1) and a new, dry-storage facility (ISF-2), commissioned in April 2021. Fuel is being progressively transferred to the new facility. At present, about 2000 of the about 20,000 used fuel assemblies have been transferred to ISF-2.

Radiation levels

As part of its mission from 25 to 28 April, the IAEA assessed radiation levels in the Chernobyl exclusion zone, including in the excavations made by the Russian forces. The results ranged from an average of 1.6 mSv/yr on roads near to the excavations to 6.5 mSv/yr in the excavations themselves. Typical exposures to background radiation for people worldwide range from about 1.5 - 3.5 mSv/yr, but can be more than 50 mSv/yr, depending on geology, altitude and other factors. Workers at the Chernobyl site have an authorized annual dose limit of 20 mSv/yr, three times higher than that recorded by the IAEA in the excavations.

Radiation dose levels recorded by the IAEA in the Chernobyl exclusion zone in April 2022, typical worldwide annual exposure from background radiation, and the authorized limit for workers at the Chernobyl nuclear plant (source: IAEA)

Staff/shift rotation

The SNRIU reported on 20 March that about half the staff at the Chernobyl site had been able to rotate and return to their homes for the first time since 23 February. A day later the regulator confirmed that the remainder of the staff had been able to rotate and return home too. The new work shift included two supervisors instead of the usual one to ensure there was back-up available at the site.

A second staff rotation took place on 10 April. The staff had to be transported by boat on the Pripyat River, which IAEA Director General Rafael Mariano Grossi said "underlined that the situation... remained far from normal."

On 21 April the SNRIU told IAEA that staff rotations were "taking place regularly and according to plan."

Non-power facilities

The SNRIU reported on 6 March that a subcritical assembly at the Kharviv Institute of Physics and Technology came under fire. A substation was destroyed, and air conditioning systems and heating lines were damaged.

The facility, known as Neutron Source, is used for research and to produce radioisotopes for medical and industrial applications. The facility is always subcritical* and contains very little radioactive material. As such, the IAEA concluded that the damage reported to it would not have had any radiological consequences.

The facility was put into a “deep subcritical state” on 24 February.

The IAEA inspected the facility during the week commencing 7 November. It reported that whilst the facility was heavily damaged by shelling, there was no indication of radiological release or diversion of declared nuclear material.

* A subcritical fission device does not release a sufficient number of neutrons to sustain an ongoing series of reactions. 


Notes & references

General sources

IAEA web portal on the conflict in Ukraine
International Atomic Energy Agency, Nuclear Safety, Security and Safeguards in Ukraine: Summary Report by the Director General, 24 February – 28 April 2022 (28 April 2022)
Situation of nuclear facilities in Ukraine, Institut de radioprotection et de sûreté nucléaire, (1 March 2022)

References

1. WENRA position on the safety situation of Zaporizhzhia NPP after reported shelling activities, Western European Nuclear Regulators Association (10 August 2022) [Back]
2. National Report On Compliance of Ukraine with Obligations under the Convention on Nuclear Safety, State Nuclear Regulatory Inspectorate of Ukraine (June 2019) [Back]
3. Nuclear Safety, Security and Safeguards in Ukraine, 2nd Summary Report by the Director General, International Atomic Energy Agency (6 September 2022) [Back]


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