Today, Sunday, there’s been much conflicting and confusing information about the Fukushima nuclear reactors, from both the plant operators, Tokyo Electric Power Company (TEPCO), and the Japanese Government. What does seem certain is that the three reactors that were in operation at the Fukushima Daiichi plant when the earthquake struck are now in serious trouble. At the adjacent Fukushima Daini plant one reactor is also in serious trouble. The problem with all four of these reactors has been caused by the failure of the primary coolant systems, because the earthquake knocked out power supplies. The secondary (emergency) coolant systems, powered by diesel generators, kicked-in ok but were then knocked out by the tsunami. No power, no coolant systems: the reactors overheat and there’s a real risk of meltdown (in the sense of a reactor’s containment structure being breached, and a hellish radioactive brew being released into the environment).
All four reactors shut down automatically when the earthquake struck; but what you have to bear in mind is that a nuclear reactor is not like an electric bar fire: you can’t just switch it on and off. A shut-down inhibits the nuclear fission process, but it doesn’t stop a whole host of other nuclear and chemical reactions from still taking place in the reactor (many of which are still not properly understood). These reactions create heat/pressure, and it’s why reactors, and the fuel rods within them, have to be kept cool for long after the fission process has stopped.
There’a also been confusing/conflicting reports today about the Onagawa power plant (three reactors), which is approx. 120 km (75 miles) north of the Fukushima plants, and the nearest nuclear installation to the epicentre of the earthquake. An emergency was declared after very high radiation levels were detected at the Onagawa plant, which is managed by the Tohoku Electric Power Company, who claimed this was due to radiation from the Fukushima Daiichi nuclear accidents and not from the plant itself.
Almost a quarter of a million people have been evacuated from the vicinity of the Fukushima nuclear plants, which would have made world headlines on its own, if it were not for the fact that it’s a result of one of the worst natural disasters in history. If it’s true that the high levels of radiation in Onagawa are a result of what’s happening in the Fukushima plants, 120 km south of Onagawa, isn’t the 20 km exclusion zone around the Fukushima plant a bit worrying?
I could go on and on with this, dear reader, but would probably only heap confusion upon confusion. The fact is that the outside world doesn’t really know what is going on, as is usual with the nuclear industry.
Nuclear power creates all sorts of nasty waste products. With the natural concern there is about reactors blowing-up, or melting down, or going-side ways, this seems to have been overlooked. The most obvious one is spent fuel. All of the plants in the effected area have spent fuel on site, and it’s a lot less well protected than the reactors; and it has to be kept cool (see what I said above), which is a bit difficult when there’s no mains electricity. Also, whether this spent fuel is stored in water or in casks one has to wonder how well it has stood up to the tsunami?
This spent fuel is eventually shipped to companies who either treat it as waste or re-cycle it. Within the earthquake zone, Japan Nuclear Fuels (JNF) has an enrichment facility (storing tons of radioactive material) in Rokkasho Muri, in the Aomori Prefecture. This processing plant is on a spit of land surrounded by sea on two sides. One would like to assume that when they built the plant they took the risk of tsunamis into account, but what about the lack of mains electricity?
Sleep tight, and don’t have too many nightmares.