California

Those are the two commissioning dates, construction of Diable began the same year that SONGS went online.

The Nuclear Regulatory Commission's estimate of the risk each year of an earthquake intense enough to cause core damage to the reactor at Diablo Canyon was 1 in 23,810, according to an NRC study published in August 2010.

https://en.wikipedia.org/wiki/Diablo_Canyon_Power_Plant

I'd like to see it stay open until an equivalent generation capacity SMR fleet is dispatched.

I've visited a number of NGas plant, they use the same tubines and generators (basically) and are never in the pristine condition that Diablo presents. The place looks like it was built last week.