> If we have a few more Fukushimas, we might ruin the ocean forever.

I could be wrong, but, IIRC, coal power has actually created more radioactive pollution than nuclear energy. It's just a far, far larger volume of less concentrated pollution.

Also, Fukushima-style pollution isn't "forever." The most radioactive stuff also decays the quickest, so it disappears relatively quickly. It looks like most of the pollution from Fukushima was caesium-137, which has a half-life of 30 years.

There's no small irony that after Chernobyl, all evidence is that animal life has actually thrived in spite of the radiation, and if anything, the most sensitive species to radiation is us. Another commenter has already pointed out that there is vastly more radioactivity in the sea than anything we can add.

A few million gallons of nuclear contaminated water into the ocean is nothing, it'll dilute to next to nothing, Nuclear homeopathy, if you prefer.

There's 4.5 Billion metric tons of uranium in the ocean already.

https://www.osti.gov/biblio/6191296