As I write this the news about the Japanese nuclear plant emergencies seems to be getting cautiously worse. Morning reports described a single reactor that was recieving insufficient cooling due to power loss. Now the news says there’s a second reactor with similar probems, and possibly a third with a fire on site. It’s a race now. The main power is cut to the reactor cores, the secondary diesel generators have failed somehow, and the tertiary battery-powered systems are apparently unable to pump enough cooling fresh water through the hot rods to keep them from turning the water that is there into radioactive, pressurized steam. If the diminished flow of water is less than the amount being boiled off the rods will eventually be exposed to the air, at which point they will melt. A ‘nuclear melt down’.

That probably won’t happen. Batteries are being delivered to the site to maintain the lessened flow. (A task currently being handled by US Air Force jets. How does a military jet deliver a battery to a power plant I wonder?). Eventually the secondary or primary power will come on and complete cooling will happen. Right?

Already one of the reactors has had to have some amount of steam vented into the open air, and residents within 6 kilometers are being advised to stay indoors. I have no idea what the impacts to residents in the region might be, either in the best or the worst case scenarios.

But the impacts to the climate are necessarily bad, even in the best case. In the worst case they might be terrible.

Increased build-out of nuclear power is likely a necessary but not sufficient condition for preventing worldwide climatic catastrophe. Wind, solar, algae and geothermal are of course superior energy generation technologies, but they are relatively immature practices unlikey to be able to deliver the several terawatts of power needed to supplant fossil fuels anytime in the near or even midterm future. Absent a conservation revolution, the practical alternative is that coal and petroleum plants that should have been mothballed twenty years ago will continue to empty their respiratory clogging, climate destabilizing waste into the air at a vast daily rate for decades to come. Nuclear power plants are at least technically able to be deployed at large scale within a few quick years. Siting a nuclear plant takes much longer than that in practice, but principally because residents are deeply suspicious of having their ugly threatening bulks lurking on the skyline. In the last few years there seems to have been a significant shift in the affections of green thinkers, and that shift seemed plausibly destined to filter down through the larger populace into actual power reactors getting actually built and plugged into the grid.

That perceptual shift has limits (as we’re presently witnessing with the resistance to the shipping of surplus nuclear parts through the St. Lawrence). It doesn’t matter these nuclear installations just absorbed the largest Japanese earthquake in recorded history. It doesn’t matter that they were built by GE in 1971 using rods-in-a-pool technology that is only slightly related to the relatively self-correcting closed-container sytems that could be erected tomorrow. People are going to look at what happens now and in the next few hours, and they are quite reasonably going to ask: do I want to receive a 3 kilometer evacuation warning of my own?

The primary safety systems failed. The secondary systems failed (I think). The tertiary systems turn out to be insufficient. All of which is happening in a country with a disaster readiness culture, no lack of forewarning about the possibility of earthquakes, and engineering standards as high as anywhere in the world. By late tonight we might just find out if popular opinion is going to turn against what is possibly only bridge energy source we have available to keep our climate predictable and stable.

Technical updates are available at the Union of Concerned Scientists website. I will probably edit this post tomorrow to be less emabarrasingly panicky.

(update 14.3.11: I didn’t. I’m still panicky.)