The problem at Fukushima Daiichi was not refurbishment problems: it was the fact that the emergency batteries and generators were in the basement and accessible from the sea-facing side of the structure.

Fukushima Daini did not have those problems, and thus not much drama happened at it:

* https://www.researchgate.net/figure/Comparison-of-flood-dama...

* https://hbr.org/2014/07/how-the-other-fukushima-plant-surviv...

The two plants are 12 km apart and got hit with the same tsunami.