A recent article on Diablo Canyon has reminded me of some of the early history of the plant.
Back around 1970, before the discovery of the Hosgri Fault, it was thought that the strongest earthquake that could hit the plant would cause a ground acceleration of 0.2 G. So it was agreed that the plant would be built to withstand 0.4 G — a so-called “double design” earthquake.
Then the Hosgri was discovered, and the maximum acceleration that could hit the plant was upped to 0.75 G. So the next few years were spent scrambling to show that the plant could handle that.
But guess what?
The “double design” concept was conveniently forgotten, presumably because there was no way the plant could be certified to withstand 1.5 G. It was this fact, more than any other, that caused me to become an opponent of Diablo.
Now, with the discovery of additional faults, the maximum acceleration is thought to be 0.8 G, and PG&E says the plant can withstand 35 percent more than that, or about 1.1 G. But the double design concept is still conveniently forgotten. Very suspicious indeed!