Land Of The Rising Core Temperature

Stratfor has a very blunt and sobering rundown of the problems at the Fukushima Daiichi Nuclear Plant.  The good scenario is Three Mile Island.  The bad scenario is Chernobyl.  Saturday, an explosion at the plant signaled the failure of the cooling system and engineers are resorting to using seawater to flood the reactor containment vessel to cool the nuclear fuel down.

First, a bit of a primer on how a nuclear plant works.  It's basically a big chunk of nuclear fuel that gets really, really hot.  That heat is contained by control rods (which soak up the radiation) and by coolant (the plant is a steam reactor).  The excess heat turns the water in the coolant pipes into steam, and the steam turns the generator turbines and creates electricity.  The steam then cools off and becomes water again where it goes back to the pipes at the reactor core and the cycle continues.

The earthquake messed up the cooling system power.  Yeah, that runs on electricity.  Normally they'd kick in the backup generators and did, but the tsunami then flooded the backup generators.  Without it, it's like a radiator with no coolant in it.  In that scenario, your engine overheats and locks up, but the engine stops.  If this doesn't work in a nuclear power plant, the nuclear fuel will, well, go nuclear.  It will get so hot that it will melt the steel containment vessel and then the really bad stuff starts to happen.

And so now the question is simple: Did the floor of the containment vessel crack? If not, the situation can still be salvaged by somehow re-containing the nuclear core. But if the floor has cracked, it is highly likely that the melting fuel will burn through the floor of the containment system and enter the ground. This has never happened before but has always been the nightmare scenario for a nuclear power event — in this scenario, containment goes from being merely dangerous, time consuming and expensive to nearly impossible.

Radiation exposure for the average individual is 620 millirems per year, split about evenly between manmade and natural sources. The firefighters who served at the Chernobyl plant were exposed to between 80,000 and 1.6 million millirems. The Nuclear Regulatory Commission estimates that exposure to 375,000 to 500,000 millirems would be sufficient to cause death within three months for half of those exposed. A 30-kilometer-radius (19 miles) no-go zone remains at Chernobyl to this day. Japan’s troubled reactor site is about 300 kilometers from Tokyo.

The latest report from the damaged power plant indicated that exposure rates outside the plant were at about 620 millirems per hour, though it is not clear whether that report came before or after the reactor’s containment structure exploded.

So at this point we don't know if this will work.  But that's why people are throwing around Three Mile Island and Chernobyl at this point, because we have a full-fledged nuclear plant disaster on our hands.  If the containment vessel was damaged by the earthquake and this thing is going into meltdown, we're talking "pretty much worst case scenario" here.

This is bad, people.  If Japan's plan is to flood the reactor with seawater, it means they have no other options at this point to prevent a complete meltdown.