system
Given the following post, respond as if you're commenting on Reddit:
human
Why can't the water being stored at Fukushima be reused for cooling?

I'm sure it has been asked before but I cannot find the answer. Why can't the massive amounts of radioactive water being stored at Fukushima be reused to cool what is left of the reactors?
gpt
Short answer? It can be.

But we know the water is contaminated, and possibly leaking off-site. Using contaminated water makes the potential leaking water more dangerous. (Even if it's a tiny change) It's also a bad image for Tepco. "Trpco skipping proper disposal of waste water by pouring it out onsite."

Safe and unsafe levels are defined by amount/volume. For anything. Rat poop in your food. Chemical waste. Rad waste. To make water safe for dumping, you filter it, dilute it, then dump it in the ocean far from land, which does more dilution. How much work before dumping is usually based off of legal standards for country of origin, which may or may not have a scientific backing.

All forms of liquid waste have this problem, but nuclear is worse. Chemical waste can be cleaned chemically and mechanically. Rad waste can need a centrifuge to ensure you pick up all the isotopes. Heavy water is still water, chemically speaking. So a chemical rreaction won't remove it. Ditto for any other isotope of a normally safe element. Some like cesium or lead are easy. They're bad, whether active or not.

Rad waste is also politically more sensitive. Everyone always thinks of fuel pins and control rods. But a ton of waste is low level stuff that's legally classified as waste because of where it was used. Like paper towels or brooms.