The electrical lines to the Chernobyl nuclear complex have presumably collapsed as a result of bombardment. What this means for the cooling of the fuel components and the measurement systems.
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| [Chernobyl Nuclear Power Plant, Ukraine] |
The electrical supply to the old Ukrainian nuclear power facility Chernobyl has been switched off. Power cables were damaged by shelling, according to Ukraine's grid operator Ukrenerho. Because combat has persisted north of Kyiv, it is presently unable to carry out the essential repairs, according to the statement.
The state-owned Ukrainian nuclear energy corporation Energoatom is now warning that radioactive substances may leak from the nuclear complex since the spent nuclear fuel on site cannot be adequately guarded and monitored without a power source.
The SSSCIP, Ukraine's official communications service, declared on Twitter that the 750-kilovolt high-voltage connection between Chernobyl and Kiev was temporarily shut down "due to the damage inflicted by the occupants." As a result, the power plant at Chernobyl and all nuclear facilities within the exclusion zone are without electricity.
In the worst-case scenario, around 20,000 fuel components were stockpiled on site, according to the authorities. They'd have to be kept cool all the time. This, however, is only viable if there is power. The pumps would be unable to cool constantly if they were not connected to the electricity grid. As a result, the temperature rises in the storage pools, evaporation occurs, and radioactive chemicals are discharged into the atmosphere.
For the past 20 years, fuel components have been deteriorating in Chernobyl
According to the Energoatom statement, heating the 20,000 used fuel components might result in the "emission of radioactive chemicals into the environment."
"The final reactor block at Chernobyl was shut down in 2000, and the fuel components there have been degrading for at least 20 years," says Sven Dokter of the Cologne-based Society for Plant and Reactor Safety (GRS). "This suggests that the degradation rate is currently extremely low." Even if the pumps in the spent fuel pools fail and all the water evaporates over many weeks and cannot be replenished, the heat created by the old nuclear fuel components would not be sufficient to harm the coating."
However, without electricity, there is no ventilation within the system to safeguard the injured reactor. The SSSCIP cautioned that the employees on the scene would thereafter be exposed to a potentially lethal amount of radiation. Furthermore, because the plant's fire suppression equipment is inoperable, there is always a risk of fire.
The International Atomic Energy Agency tweeted about the outage as well. The power outage, according to Secretary General Rafael Grossi, undermines one of the most essential security pillars. The IAEA, on the other hand, "does not perceive any serious effects on security in this situation." The thermal capacity of the spent fuel storage pool and the volume of cooling water in the Chernobyl nuclear power station are adequate to remove heat efficiently without the use of electricity.
No shift change for last two weeks
The IAEA has previously warned that the nuclear power plant was becoming increasingly isolated from the rest of the globe. Since the commencement of the Russian takeover on February 24, 210 technicians and local security personnel have remained on duty without interruption for nearly two weeks. Because there have been no more shift changes since Russian military gained control of the former power facility.
Despite the fact that the employees are given water and food, their position is rapidly deteriorating. The IAEA is no longer linked to the monitoring equipment that ensures all radioactive material is where it should be. In the limited region, more than 2,000 individuals typically work in rotating shifts.
Chernobyl had a nuclear tragedy in 1986, when an explosion occurred in a nuclear reactor of the type RBMK-1000. Graphite was utilised as a moderator in this reactor, which is the material that slows down the neutrons produced during nuclear fission. Water is employed as a moderator in the pressurised water reactors used in today's nuclear power facilities. The burning graphite created a lot of heat and burst during the Chernobyl tragedy, causing radioactive particles to reach high elevations and spread.
Furthermore, the reactor was less secure than today's reactors, which are surrounded in a containment composed of solid reinforced concrete. This safeguard, intended to prevent radiation from being discharged, was missing from the Chernobyl nuclear power facility. Today, radioactive waste is still kept on the power station site.
Following the disaster, a protective cover known as a »sarcophagus« was constructed. Over this sarcophagus, a new confinement named New Safe Containment (NSC) was created in the 2010s. It is designed to keep radioactive chemicals from escaping for more than a century.
So does the local blackout pose an acute danger?
"The nuclear core of Chernobyl Unit 4 has been destroyed for so long that you no longer require active pumping power for active cooling, as with a reactor that has just been shut down," radiation specialist Clemens Walther of the University of Hanover told SPIEGEL. "First and foremost, I would not consider the Chernobyl power outage to be a short-term emergency," the expert explains.
However, power is required in the long run to keep the NSC, the massive second metal shell that surrounds the damaged reactor, intact. The NSC is made up of two metal shells connected by a hollow. "Air must circulate in this hollow, not least to avoid humidity-induced corrosion." For a few days, the failure of the fans is not an issue.
Nonetheless, the Chernobyl power outage is concerning and unacceptable, according to the expert: "There will be no huge radiation risk from one day to the next, but it's about the next several weeks and months." Currently, depending on how long the diesel supply lasts, the emergency lights and vital measurement chores are most likely handled by the emergency power supply.
The diesel generators in Chernobyl have enough fuel to function for 48 hours, according to Ukrainian Foreign Minister Dmytro Kuleba. In the case of a power outage, active nuclear power facilities are prepared to employ emergency diesel generators. However, in times of conflict, fuel might be limited. Especially if the conflict lasts a long period.