“will probably destroy the internal workings of these reactors and likely require extensive replacement of a lot of expensive components”
From what I understand is that these are very old reactors that were due to be decommissioned rather soon anyways. Either way Japanese firms are extremely nationalistic and will almost always put country ahead of profit so I’m positive every decision is being made with safety solely in mind.
I had read that this was an older design but I didn’t realize they were that close to the end of useful life. Perhaps this will prove to be an opportunity to get a modern design built to replace this unit, if they can salvage it.
I also heard they were preparing to pump boric acid into one of the units to damp the nuclear reaction, and that implies near fatal damage to that unit. It will probably prove to be difficult to decommission but I do not think it will pose the risk of a major release, on the scale of a Chernobyl event.
I keep coming back to Chernobyl as the ultimate worst possible case accident for a nuclear reactor. The design of even these older model Japanese reactors are light-years beyond Chernobyl in safety and the chances of an extreme accident that exposes a burning core are extremely remote.