Earlier quoted context omitted.
Were the safer designs available in 1971?
Yes. Pressurized water reactors are very old, they were developed around the same time as boiling water reactors, in the 50s. Their superior safety has been known for a long time as well, which is why all 58 French reactors active today are PWRs (and most of those in the US are as well). That being said, it is still probably a bad idea to put a power plant in a place which is known to be exposed to tsunami...
...Especially in the country which originated the word tsunami