A type of black fungus has been discovered inside the Chernobyl nuclear reactor, and it's feeding on the radiation. How is it able to survive in such conditions and what does this mean for the future?
What happened in Chernobyl?
On 26th April 1986 Chernobyl nuclear power plant exploded, creating what is considered the worst nuclear disaster the world has ever seen. The explosion occurred at reactor 4 and was partly the result of operators who disobeyed the plant’s safety regulations in order to test the electrical systems. It caused the reactor to become dangerously unstable which combined with flaws in the reactor’s design made the disaster inevitable. In most nuclear reactors, water is used to remove excess heat and steam, but the RBMK-1000 used graphite. As the nuclear core produced more steam and heat, the core became more reactive, instead of less, thus creating a unstoppable positive-feedback loop. Since at the time the Chernobyl power plant, unlike most others, did not have a fortified containment structure massive amounts of radiation escaped into the environment. Long-term effects of this are still unknown.
What is the “Elephants’ foot” and why is it so dangerous?
The thermal energy generated by the Chernobyl nuclear power plant explosion reached such levels that it caused the core and its reactor rods to meltdown. It reached estimated temperatures of between 1,660°C and 2,600°C which caused it to form a lava-like mass containing not only uranium fuel rods but also the graphite moderators, boron control rods, sand etc. As the catastrophe continued to worsen, this mass now nicknamed the Elephant’s foot, melted through steel beams and several concrete floors before falling into the basement where it remained till this day. At the time it was discovered (eight months after the explosion) it emitted deadly levels of ionizing radiation, enough to cause death in 300 seconds. The radiation levels, even though considerably lower today, are still incredibly high and dangerous…for humans that is, but there are some organisms that have adapted to these conditions and are actually using the radiation to their benefit.
The fungus that's thriving in these conditions
In 1991, just five years after the nuclear reactor exploded scientists have discovered a fungus that, despite the lethal emission of radiation, is growing inside the Chernobyl power plant. However, they only recently discovered that its properties could be used to protect us from radiation. This particular fungus is called Cryptococcus neoformans, but it’s not the only one of that kind.
They are called Radiotrophic fungi and not only are they able to survive in such conditions, they take advantage of them by performing radiosynthesis- a process of converting gamma radiation into chemical energy and food. So what allows them to do this? Melatonin- a pigment that is also found in our skin.
Scientists still don’t completely understand how this happens, but agree that these and future discoveries could have a huge effect on space travel. For example NASA scientists are considering extracting the melanin from Cryptococcus neoformans as a way of making cost-effective sunscreen that could protect astronauts from radiation-caused damage when in space.
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