It shouldn't be too surprising since the universe and earth have been and remain naturally filled with radiation for billions of years. The heat that keeps magma warm in the earth comes 50% from radioactive decay of uranium and its daughters. Life today is based on plants and microorganisms absorbing radiation emanating from a giant nuclear reactor in the sky.
This is just a twist on how it's always been done.
This is just a twist on how it's always been done.