I am not certain any corruption was involved but there was a severe lack of safety and hazardous analysis thinking.
Today modern safety engineers develop analyses that consider the type of things that might go wrong. The consideration of a tsunami that was higher than ever seen would be understood. Storage of spent fuel rods would never be undertaken in the same area as the reactor and certainly would not be stored where water could accumulate and cover the fuel rods. I would also think the wall would have been built higher, (maybe some corruption was involved in the desire to avoid the expense, I do not know.)
However, we will need nuclear power soon, (if not already) and the cost of doing it right must be applied. People have looked at the density of other carbon free alternatives and they take over the countryside because of their low density. We will need the higher density in many places.
No rush.