There was a tsunami in the Severn estuary near where I live in 1607.
There are two nuclear power stations there now. Apparently there are
two possible reasons for the tsunami& it could happen again.
?????????
Are they tsunami proof?

What do you not understand about UK stations being of a different design
from the BWR in Japan and not needing the pumps that were the only
critical thing damaged by the tsunami?

The pumps and the standby generators. And when they did ship some generators
in the plugs weren't right.