I keep hearing about and reading people freaking out about Fukushima Daichi Nuclear Power Plant, and the horrible disaster that is occurring there, but I think people need to understand just what is going on there, and why what is happening there actually shows how well the nuclear power industry can handle disaster. There are a number of things that I would suggest anyone considering the issue keep in mind.
First, the entirety of Japan was just hit with the strongest earthquake ever recorded at 9.2, followed shortly by a 20 ft Tsunami. Second, the plant began construction in 1967, and began operations in 1971 – making it a forty year old reactor based on technologies developed twenty years or so before that. It is a plant with 6 nuclear reactors, made with 3rd, 4th, and 5th generation boiler water reactor designs.
So what happened? From what I can gleen, the earthquake took the reactors off line, forcing the operators to perform emergency shutdown procedures (commonly called a scram) which would normally not be an issue. After a scram, the primary coolant – the water inside the reactor itself, needs to continue circulating in order to remove decay heat – heat generated by the radioactive decay of short lived radioactive molecules (like Nitrogen and Oxygen that have picked up an extra couple of neutrons), and spent fuel molecules.
In the event of an emergent shutdown, power is pulled back from the grid (or other reactors in the same plant) in order to run coolant pumps in the primary system and keep the water circulating. Unfortunately, all 6 reactors went offline, and the grid was more or less destroyed by the earthquake and following tsunami. As a backup to this method, a set of diesel generators are located on site to supply emergency power for cooling for up to 8 hours before needing to be refilled. These generators were placed in an elevated location in order to account for the possibility of just such a tsunami.
It’s just that no one ever thought they’d get hit by one this big. (Remember, this was back in the 60′s when they designed these plants).
As a backup to the backup, generators can be brought in, and they were – but the power adapters were incorrect (this is hearsay, but seems reliable to me). In any case, such a solution is time limited based on the amount of fuel you have anyway. With the general devastation in Japan, it seems likely to me that diesel may be in short supply.
So now we’re in a blackout; no off-site power available and no generator power available, so we’ve got a big pressure vessel full of water getting heated, increasing temperature and pressure.
The next available step would be the addition of cold water into the core – a bad option because cold water actually causes more nuclear reactions to occur, but possible in a very slow and controlled manner – slower than would be useful or really helpful. The final resort would be to try and drain the water from the core and allow the core to go ahead an meltdown – within it’s containment. The problem with that is that if you’re allowing these metals to be hot enough to melt, how do you keep the containment from melting? It’s the safest last option though, because it doesn’t involve any explosions of steam dispersing radioactive material into the atmosphere.
That’s not even the entire issue though – damage from the quake and tsunami have caused the spent fuel storage facilities to fail, uncovering the spent fuel rods and causing them to burst into flame.
Here’s the rub though: do you really feel scared by it? Did the world feel scared when Chernobyl went up? TMI was a partial meltdown with negligent radioactive release, and yet it stopped nuclear industry expansion in the US for 30 years. Yes it sucks, yes it really is a worst case scenario for everyone involved, but because our knowledge and foresight has been developed over the last 60+ years of nuclear energy, it’s no longer scary. It sucks, it’s bad, and it’s scary for the people having to try and deal with this disaster scenario.
We know how to deal with it, we understand what we’re doing, we understand how to combat it. We understand.
Science: +1; Fear: 0.