Between the direct costs (at the plant), and still having a 1,000 sq. mile exclusion zone 40 years later, Chernobyl really isn't overshadowed by the potential of thousands of dams.
And by the hellish standards of that war - https://en.wikipedia.org/wiki/Casualties_of_the_Russo-Ukrain... - 200 to 300 dead is a rounding error.
That is the weakest aspect of hydro - it causes massive green house gas releases during and in the aftermath of construction, and destroys vast ecosystems.