The last operational reactor at Ukraine’s Zaporizhzhia nuclear power plant was shut down on Sunday to reduce the risk of a radiation disaster.
SAPORIZHZHIA, Donetsk Oblast — The last operational reactor at Ukraine’s Zaporizhia nuclear power plant, the largest in Europe, was shut down on Sunday to reduce the risk of a radiation disaster amid ongoing fighting.
The move became possible after the plant was reconnected to Ukraine’s electricity grid.
Here is a look at the situation in the plant after 200 days of war in Russia:
Fighting near the plant has fueled fears of a disaster like that of Chernobyl in 1986, where a reactor exploded and spewed out deadly radiation, contaminating a vast area in the world’s worst nuclear disaster.
The power plant, one of the 10 largest nuclear power plants in the world, has been occupied by Russian forces since the first days of the war. Ukraine and Russia have shared blame for the shelling of the plant, which did not damage its six reactors or spent fuel storage facilities, but repeatedly hit power lines and some auxiliary equipment.
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While Zaporizhia’s reactors are protected by a reinforced containment that could withstand a stray shell or missile, an interruption in power could disable the cooling systems essential to the reactors’ safety. Backup diesel generators can be unreliable.
After the plant was demolished from the transmission lines following a fire caused by shelling on September 5, only one reactor remained operational to power cooling systems and other essential equipment in what is known as island mode.
RISKY “ISLAND MODE”
Operation in “island mode” provides power for residual heat removal from the reactor cores and spent fuel pools.
Experts say it is very unreliable. They point out that if the diesel generators fail, a meltdown could occur within hours.
If the reactor is already shut down, the risk depends on the time since shut down. The less time has passed, the more cooling is required.
While the Zaphorizhzha spent fuel pool is within the facility’s containment perimeter, a major reactor accident would likely affect the pool as well.
WHAT IS HAPPENING NOW?
Ukrainian nuclear operator Energoatom said the restoration of one of the power lines connecting the plant to the country’s power grid allowed engineers to shut down the last operational reactor.
Energoatom said the move was necessary to prevent a situation where the power plant would have to rely solely on backup diesel generators to keep the reactors cool and prevent a meltdown. The company chief told The Associated Press on Thursday that the plant has only had diesel fuel for 10 days.
The International Atomic Energy Agency, the UN nuclear regulatory agency, which has two experts at the plant, confirmed to the AP on Sunday that its last reactor was shut down after external power was restored.
IAEA Director-General Rafael Grossi has called for a security zone around the facility to avert disaster, but fighting continued.
https://www.kvue.com/article/news/nation-world/ukraine/ukraine-nuclear-plant-explainer/507-49db15aa-fb0b-40ef-9cec-6dcce2b746d0 Nuclear power plant in Ukraine shuts down: why it happened