[null and void]

We have never dumped this much nuclear contamination into an ocean before.

Zatso?

[justa-hairyape]

Yes. That is so. Nuclear explosions are designed to convert mass into energy. E=MC2. What Fukushima has been dumping into the ocean is radioactive mass.

[ransomnote]

The sum of those nuclear blasts did not put as much radioactive material into the ocean and atmosphere as Fukushima.
Bombs are highly efficient in converting matter into energy - hence the astonishing heat/light/sound display of nuclear explosions.
Fukushima had a few small explosions, nothing on the order of the blasts you show. Less nuclear material was converted into energy - more nuke material flowing into the air, land and ocean.