Comment by baranul

> I wonder what the reason is?

Different reactions, by different types of governments and politicians. Chernobyl was also seen as an European problem, thus numerous other nations and organizations were more significantly involved.

With Fukushima, the government and companies involved had greater control over the flow of allowed information and reporting. For instance, Korea was greatly concerned about Fukushima, but could do little to intervene or interfere with internal Japanese affairs.