LONDON, Oct 11 (Reuters) – Repeated shelling of the Zaporizhzhia nuclear energy plant in southern Ukraine has raised the opportunity of a grave accident simply 500 km (300 miles) from the location of the world’s worst nuclear accident, the 1986 Chernobyl catastrophe.
The Worldwide Atomic Vitality Company (IAEA), which has repeatedly expressed considerations over the shelling of the plant, has proposed the institution of a nuclear security and safety safety zone across the plant.
What nuclear materials is at Europe’s largest nuclear energy plant, what are the dangers and why are Russia and Ukraine combating over it?
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WHAT IS IT?
The Zaporizhzhia nuclear energy plant has six Soviet-designed VVER-1000 V-320 water-cooled and water-moderated reactors containing Uranium 235, which has a half-life of greater than 700 million years.
Building started in 1980 and its sixth reactor was linked to the grid in 1995. All six reactors at the moment are in chilly shutdown after reactor No. 6 was shut down on Sept. 12.
A chilly shutdown means the reactor’s temperature is under boiling level however electrical pumps shifting water by way of the reactor core should nonetheless preserve working to chill the gas.
The plant is not producing electrical energy.
WHAT ARE THE RISKS?
The largest threat is from overheating nuclear gas, which may occur if the ability that drives the cooling programs was lower. Shelling has repeatedly lower energy strains.
The plant misplaced its final remaining exterior energy on Oct. 8, leaving it reliant on diesel mills for greater than a day, the Worldwide Atomic Vitality Company mentioned. The facility line was restored on Oct. 9.
Earlier than the battle, the plant had 4 high-voltage energy strains giving it entry to the grid in addition to a number of backup strains.
COULD THE REACTOR MELT DOWN?
Pressurised water is used to switch warmth away from the reactors even when they’re shutdown, and pumped water can also be used to chill down eliminated spent nuclear gas from the reactors.
If the ability was lower and auxiliary programs corresponding to 20 diesel mills (which have sufficient diesel for 10 days) didn’t preserve the reactors cool, then the gas may meltdown and the zirconium cladding may launch hydrogen.
A meltdown of the gas, which stays extraordinarily scorching for a while even after the reactor shutdown, may start a fireplace or explosion that might launch a plume of radionuclides into the air the place they could possibly be unfold over a big space.
The Chernobyl accident unfold Iodine-131, Caesium-134 and Caesium-137 throughout components of northern Ukraine, Belarus, Russia, northern and central Europe.
WHAT ABOUT THE SPENT FUEL?
In addition to the reactors, there may be additionally a dry spent gas storage facility on the web site for used nuclear gas assemblies, and spent gas swimming pools at every reactor web site which might be used to chill down the used nuclear gas.
“The basins of spent gas are simply huge swimming pools with uranium gas rods in them – they’re actually scorching relying on how lengthy they’ve been there,” Kate Brown, an environmental historian on the Massachusetts Institute of Expertise whose e-book “Guide for Survival” paperwork the complete scale of the Chernobyl catastrophe, mentioned in August.
“If contemporary water is just not put in, then the water will evaporate. As soon as the water evaporates, then the zirconium cladding will warmth up and it could possibly catch fireplace after which we now have a foul state of affairs – a fireplace of irradiated uranium which could be very just like the Chernobyl state of affairs releasing an entire advanced of radioactive isotopes.”
An emission of hydrogen from a spent gas pool brought about an explosion at reactor 4 in Japan’s Fukushima nuclear catastrophe in 2011.
In line with a 2017 Ukrainian submission to the IAEA, there’s a whole of greater than 2,200 tonnes of nuclear materials excluding the reactors, in response to the doc.
WHO CONTROLS IT?
After invading Ukraine on Feb. 24, Russian forces took management of the plant in early March.
Particular Russian army models guard the ability and Russian nuclear specialists are on web site. Ukrainian workers proceed to assist function the plant.
After Russian President Vladimir Putin annexed as much as 18% of Ukraine, together with the world the place the nuclear plant is positioned, he signed a decree on Oct. 5 to formalise Russian management over the plant.
Ukraine’s state nuclear firm Energoatom says Russian forces have elevated their presence on the plant and has referred to as on Ukrainian workers to not conform to signal new contracts.
IAEA Director Normal Rafael Grossi has proposed the institution of a nuclear security and safety safety zone across the plant.
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Reporting by Man Faulconbridge; Modifying by Lisa Shumaker
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