Originally Posted By: benjammin
Yep, load loss won't scram the plant, it is how the operators react to the load loss that would be the likely cause of a plant critical event (not a criticality!).

Loss of grid power might well be a mandatory SCRAM event - if you lose the grid you've lost Plan A for powering the reactor cooling pumps, and if you later have to shut down you'll lose Plan B before that shutdown finishes and be down to Plan C. A SCRAM right away (when there's no load anyway) lets you complete all this before something else goes wrong, and saves nuclear fuel.

Many SCRAMs are automatic anyway - at TMI the computers successfully shut down the reactor at the start. It was decay heat the operators were struggling against. At Chernobyl the automatic SCRAM was disabled because the system would not permit such a test situation...

I found one reference to the presentation at Black Hat on taking over smart meters & shutting off power city-wide: Buggy 'smart meters' open door to power-grid botnet