I did some basic calculations to compare the energy in the radiation vs the energy required to grow 10% extra.

- If we assume they are working in the reactor we get radiation levels of something like 1 mGy/hour. But we can prop this up to mabye 500 mGy/hour since i dont know how they grew their culture

- That leads to 0.05 J of extra energy per gram of microbial bio material.

- Energy needed to grow 1g of microbial biomaterial ≈ 3.15 kJ 10% of that is 315 J per gram

The result is that:

The amount of radiation energy available is 4 orders of magnitude too small to power even a 10% growth boost.

Edit: updated with more accurate estimations.

Add in some evolutionary strategies, and you have the recipe for a good sci-fi book: a fungus in Chernobyl rapidly outpaces its competitors due to its ability to absorb radiation. Each iteration grows and reproduces faster, until it is so blindingingly fast that it begins to outpace the output the fuel rods produce.

The world rejoices as this fungus is perfect for cleaning up nuclear waste products, until we realize that it evolved to function outside of Chernobyl and begins to eat everything it can reach. Mankind launches into a desperate struggle for survival as the fungus lays waste to large swathes of land.

I'm not sure where you're going with this, but since they have actually researched how it grows, I think it's more likely your calculations/assumptions are incomplete.

For example:

> Energy needed to grow 1g of microbial biomaterial

based on what?

Edit: Maybe you meant that radiation alone wouldn't be enough for that growth, so there'd be other components that it's helping with.

Right, it could be a lack of competition in the direction of the reactor. It's a giant petri dish for anything able to withstand radiation.

> That leads to 0.05 J of extra energy per gram of microbial bio material

Over what timeframe? If that’s 0.05 J per hour and “the researchers found that fungi that faced the galactic cosmic radiation for 26 days grew an average 1.21 times faster” 26 * 25 / 21% and the numbers don’t look that unreasonable.

I also did some back of the envelope calculations. Here's what I got: the radiation level just 1 meter away from the "elephant foot" (the solidified molten core), at the time of the accident was about 1000 times lower than the solar irradiation. At 100 meters it was 10 million times lower (because of the inverse square law). Now, the radiation from the elephant foot has decreased significantly. I couldn't find a recent estimate, but I would expect it to be at least 100 times lower. So at 100 meters from the elephant foot, the radiation level is a billion times lower than what you get from the sun. There's no way any organism can "feed" on that.

There's another parameter worth considering - how efficient is it to convert sunlight vs. gamma radiation into biologically usable energy.

What if for some reason gamma radiation changes the equilibrium constants for ADP --> ATP?

Yeah, from that it sounds like the main advantage of this mold is that it gets some compensation from all that deadly radiation, and thus does better than mold which doesn't.

Sources dude...