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Comment by Animats

It doesn't kill many people, because even when there's a disaster, there's time to evacuate. But you lose an entire city once in a while.

Major reactor disasters so far:

- 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.

- Three Mile Island. Meltdown due to cooling water failure due to instrument confusion. Contained by good containment vessel. No casualties. That's what should have happened at Fukushima.

- AVR pebble bed reactor. Pebble jam, radiation leak into ground. Contained, but too much of a mess to decommission.

- Chernobyl. Meltdown and fire due to operational error during testing. Totally inadequate containment. Entire region evacuated and contaminated for decades.

- 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.

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.

Some of the recently-touted small reactor designs try to omit a containment vessel on the grounds that their design couldn't possibly melt down. That's probably not a good approach.

parent Animats 9 years ago

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