Frustrating

The news frustrates me. I check various news websites to try to find out what's going on with the nuclear reactors in Japan, and perhaps to learn why the cooling systems failed in the wake of the earthquake, and what do I find?

Seventeen bazillion links to gosh-wow videos of Japanese buildings, boats, and people being annihilated by a tsunami, videos that I really don't want to watch at all.

Thirteen bazillion links to stories about Charlie Sheen, stories that I really don't want to read at all.

I'm not arguing that links to tsunami videos or stories about Charlie Sheen should be banned, though there's a hint of schadenfreude in them that I find unappealing ("Wow, that Charlie is such a doofus; I feel much better about myself now!"). But is it too much to ask that somewhere in this glut of news we find something serious about the nuclear reactors?

I'm rethinking my position on nuclear power. I think I'm still for it generally, because I think the main alternative, widespread burning of coal, is even more unpalatable. But multiple cooling system failures in the wake of an earthquake suggest that somebody overlooked something. Maybe engineers can't anticipate everything that could fail during a very powerful earthquake, but maybe they should have anticipated their inability to anticipate and not built nuclear reactors in a geologically active area in the first place.

I'm just guessing, but I suspect that one of the issues at work here is that when you bring a reactor from normal operation to shut-down quickly, the reactor core can't cool itself by convective flow if the cooling system pumps fail. The only way to keep the cooling water from flashing into steam is to pressurize it, and the hotter it gets, the more it has to be pressurized to keep it from boiling. So at some point either a weld will fail, the pressure relief valves will open, or the water will boil, which even assuming there's any convective flow in the core to begin with will "steam-lock" the core and shut down whatever convective flow there happens to be.

Though the precise nature of the nuclear reactors in ships are classified, I believe them to employ liquid metal (such as sodium) as a primary coolant, so they don't have the immediate problem of steam formation vapor-locking convective flow. Of course, there still has to be a secondary coolant to remove heat from the "far side" of the liquid metal primary loop, which in a submarine is probably pretty easy, considering that it's surrounded by cold seawater all the time anyway. But if a land-based liquid-metal reactor had the far side of the liquid metal loop in a large pond, you'd think the pond could sink enough heat to keep the reactor from melting down for quite some time even in the complete absence of pumps.

I may be missing something, because I'm not a nuclear engineer. And it's easy to imagine a sufficiently powerful earthquake breaking the pipes that carry the molten sodium, which may be a worse outcome than the formation of steam in a pressurized-water system. Or the earthquake could cause the pond to drain. Or who knows what.

So maybe the real answer is not to build them near subduction zones in the first place. But then countries like Japan, which are pretty much one giant subduction zone, couldn't have nuclear reactors at all, unless some country with more geologically stable regions (such as China or Russia) agreed to host the Japanese nuclear reactors, which is a little hard to accept. Or maybe nuclear reactors shouldn't be operated for profit and shouldn't be considered national assets at all - maybe since a major nuclear accident would be a global problem, the ownership and operation of nuclear reactors would be globalized as well, with some supra-national agency building them in safe areas and operating them for the benefit of all.

Like that'll ever happen.

(And, parenthetically, exactly what does a "geologically safe area" really mean? When is a fault system really dead, and when it is merely biding its time? Earthquakes still happen even on mid-plate fault systems like the New Madrid system, and maybe there really is no such thing as a geologically safe area. What then? I don't know. Fusion reactors sound like a pretty good alternative to me, except for one minor inconvenience - they don't exist yet.)

But I still believe that given our appetite for energy and our inability to generate meaningful quantities of energy by means of fusion, we're more or less stuck with fission reactors. I wish it were otherwise, but it isn't.