For more than a week, the accidents in the Fukushima I power plant have dominated the news. It is too early to draw final conclusions as to what the results will be. It seems unlikely that it will reach the scale of Chernobyl, but it can still become very serious. Speaking of which: Nuclear advocates like to quote extremely low numbers of fatalities, in the 100s or 1000s, but it seems likely that a good estimate will never be produced because of the political will in the concerned countries. In order to stop the spread of radioactive materials, 100,000s of people were involved in cleaning up after the disaster. Many of them got serious doses of radiation, and it has never been officially evaluated how many of them died, likely 25,000-100,000 (Wikipedia:Liquidators). Also, slightly increased cancer rates in the population are generally not included in the studies, only deaths that can be directly traced.
In Fukushima, there does right now seem to be a serious probability that it will require the same sort of cleanup measures. Tepco has announced it is considering building a shield from concrete and sand (Reuters article). It will be very interesting who is going to take that risk and build the shield. Even though the average number of people dying in the production of nuclear energy may be quite low (although not quite as low as this claim), it will be morally very interesting who has to go and clean that thing up.
If we should draw on conclusion from this disaster, let us remember one thing: Nuclear Power is Unsafe by Design. Even after shutdown, a reactor and the spent fuel rods need constant active cooling in order to prevent a disaster. This is the real problem. The technology does not fail safely: It fails deadly. A nuclear reactor left alone is an extreme danger.
What happened in Fukushima was an accumulation of events, which were however triggered by a single original source: The earthquake produced shock waves that lead to the reactor shutdown and cut off external power, then the Tsunami removed emergency power. Each of these failures is unlikely in itself, and the occurence of all of these at the same time seems incredibly unlikely. It just happens that all these events can be triggered by only one external event, and albeit unlikely itself, it shows that the likelihood of all of them happening at once is now much higher than what one would estimate by only looking at the probabilities of each of them happening alone. I guess this is probably why the plant was not designed to withstand this series of events.
Also, let’s face it, the last thing you want to happen in your country after a serious natural disaster is an additional nuclear crisis. However, that is exactly when it is most likely to happen.
Although there is a lot that could be said about risk assessment, this is not my main point. I think Fukushima is a serious incident, and it has also shifted my own perceptions of the safety of nuclear power plants. Still, even taking all the accidents into account, nuclear power can seem like an economically and environmentally viable option. But it is important to keep an eye on nuclear power’s main problem, barely mentioned during the past few days: What happens to the waste?
While the fueling of nuclear power plants is done using Uranium isotopes 235 and 238, which do have a very long half life in the order of hundreds of millions or billions of years, the fission products that are generated from them in nuclear power plants are much shorter lived. A spent fuel rod is a serious source of heat and radioactivity for a time of several 100,000 years. It is much more dangerous than the Uranium it was originally made of, both in terms of accidents and proliferation.
For me, the burden put on future generations through nuclear waste is intolerable. In our lifetimes, we will probably not see any change in the status quo of keeping most of the high-level radioactive waste over the ground: It is still producing too much heat to be safely buried. Already this is not great, considering that we might experience times where countries are less stable than now, or some natural disasters happening. I would prefer not having to worry about crazy dictators messing around with radioactive materials to build nuclear weapons. It may be bad enough when they are in power. Too much radioactive wast lying around might also be one of the few things why I would actually worry about terrorism. Currently, most reactors are probably quite safe themselves. But as we now know form Japan, the most dangerous part, the spent fuel, is often kept outside the protective environment. So as a terrorist, you would probably target that. (Or just make sure the power plant has all power sources cut off … I guess we are very lucky that there seem to be very few terrorists around who actually want to maximise damage).
When the waste has cooled down enough, the general plan is to “bury” it. The hope is that some geologic formations have been stable for a very long time, even billions of years, so if we dispose of the waste in them it should be safe. But the earth is a very active place. What has been stable in the past, may not be in the future. Who can predict where water will enter in the next few thousand years, especially as large parts of the planet might undergo dramatic transformation due to climate change? Just because it has worked before (Wikipedia: Natural nuclear fission reactor), does not mean it is necessarily safe.
So I suggest we produce as little as possible of this waste. Nuclear power should be a technology of the past. It is not a renewable energy: without (dangerous) breeding reactors, the conventional uranium resources will last us less than 100 years at current rate of exploitation. If nuclear were to make a larger contribution to world energy production (current is ca. 5%), that number would go down appropriately. Nuclear cannot make us sustainable, let us move directly to what the ultimate goal must be: Reducing our energy consumption so that we can live off the renewable energy sources provided on our planet. There are more than enough if we use energy wisely.