Out of all major energy sources, nuclear is the safest
It doesn&#x27;t kill many people, because even when there&#x27;s a disaster, there&#x27;s time to evacuate. But you lose an entire city once in a while.<p>Major reactor disasters so far:<p>- SL-1. Steam explosion due to control rod lifted too far during maintenance. Small experimental reactor, built in the middle of nowhere (Idaho Reactor Test Station) for good reason. Inherently unsafe design.<p>- Three Mile Island. Meltdown due to cooling water failure due to instrument confusion. Contained by good containment vessel. No casualties. That&#x27;s what should have happened at Fukushima.<p>- AVR pebble bed reactor. Pebble jam, radiation leak into ground. Contained, but too much of a mess to decommission.<p>- Chernobyl.  Meltdown and fire due to operational error during testing.  Totally inadequate containment. Entire region evacuated and contaminated for decades.<p>- Fukushima.  Loss of coolant and meltdown.  Containment vessel too small, reactor cores melted through in three reactors. Containment problem well known in advance; Peach Bottom PA has same design.<p>A big, strong, containment vessel can keep a meltdown from becoming a major disaster and has done so at least twice.
Size matters; a large containment vessel faces lower pressures when all the water boils to become steam. But a good worst-case containment vessel can cost as much as the rest of the plant.<p>Some of the recently-touted small reactor designs try to omit a containment vessel on the grounds that their design couldn&#x27;t possibly melt down.  That&#x27;s probably not a good approach.