The back up batteries at Fukushima power plant were capable of being recharged, thereby avoiding a meltdown. However, the connectors hadn't been manufactured for years and nobody could jury rig something up in time to avert disaster. Humans make really stupid oversights on things that happen rarely. In hindsight it's really stupidly obvious that something should have been prepared ahead of time. But when looking forward, it's easy to overlook obvious things because the potential number of future problems is infinite. "Are we prepared for a drone attack?" The first question is, "What does a drone attack look like?" That they didn't get that far doesn't actually surprise me.