Viability of Nuclear Power - a sensible way to boil water?
by Ian at Cambridge Friends of the Earth
Advocates have long seen nuclear power as the saviour of industrial society, delivering unlimited energy, cheaply and safely for the foreseeable future. Even better, it's now seen as the only viable solution to the looming global energy crisis - think peak oil, and will come to our rescue by providing an attractive alternative to fossil fuels and their damaging influence on global climate. It's been pushed a green, clean and somehow more 'grown up' than renewable energy technologies.
Furthermore, the safety of the nuclear electricity generation to date, at least in comparison to other sources of electricity generation, is actually not that bad. Yes, anywhere between 50 and 20,000 people have been killed as a direct result of the Chernobyl disaster depending on who you listen to, but even the higher figure starts to look less damming when you compare it to the 4000 Chinese coal miners killed every year and the thousands killed by particulate pollution from coal fire power stations. Of course, the potential for disaster on a huge scale is ever present, but to date nuclear power is unlikely to rate as the most dangerous power generation technology; perhaps surprisingly that dubious award goes to hydro-electric power which, by some estimates has killed up to one million people in the last century as a result of dam bursts.
However, there are a few issues that tend to bring nuclear power's viability into question... It might be stating the obvious, but nuclear power stations only produce electricity. Electricity generation only accounts for about 30% of the UK's CO2 emissions (and 16% worldwide), so straight away we’ve got an absolute limit to the amount of CO2 that could be cut by switching to nuclear power.
Nuclear power provides about 20% of our electricity (though this proportion is declining as older reactors are taken out of service), so it could be argued that nuclear power gives us an approximate saving of 6% in our CO2 emissions; not really much when the financial and social costs are taken into account and this is before the CO2 emissions of the whole nuclear power cycle are taken into account.
No, the biggest contributors to our CO2 emissions are industry, domestic heating and transport, all of which have huge infrastructures established to burn fossil fuels directly. Whilst it's conceivable that a massive switch to electric cars could occur, the fastest growing transport sector (in terms of CO2 emissions) is aviation which must use fossil fuels. In any case, this 30% upper limit assumes that nuclear power produces no CO2 emissions, as mentioned above; a fact that the nuclear industry is keen to promote. Unfortunately, nuclear power generation, considered as a whole, does produce CO2; the only part of the process that doesn't actually produce any is the fission process itself. Uranium must be mined, processed, and turned into useable fuel, all of which are highly energy intensive processes emitting vast quantities of CO2. 99.7% of naturally occurring uranium is Uranium 238 which doesn't take part in the fission process and it is usual to increase the concentration of Uranium 235, which does take part in the fission process, in the fuel to about 15-30% by enrichment. This requires further huge quantities of energy and also leads to emissions of halogenated compounds which are, themselves, highly potent greenhouse gases. Taking these factors into account a nuclear power station can be responsible for up to 1/3 of the CO2 emissions of a gas powered power station of similar output. If we factor in the CO2 emitted from the processes involved in the storage and disposal of the resultant waste - such as manufacturing of the iron and copper cylinders currently being suggested for containing high level waste in Finland and the digging of the deep repositories the figures climb even higher and this is before the energy costs of thousands of years of monitoring are considered.
To carry on stating the obvious, nuclear power stations are huge and consequently generate vast quantities of electricity. It's simply not financially viable to produce small local nuclear power stations. The National Grid is obliged to keep a reserve electricity supply constantly available equal to the output of largest power station in case any one power station is suddenly available to produce electricity. Bigger power stations mean a larger reserve has to be kept available ie unwanted electricity generated 'just in case' with consequently larger CO2 emissions. The centralisation of power generation, due to the necessary size of the plants, also has the potential to lead to increasing loses from power transmission along high voltage lines.
Uranium is a metal about as common as tin and as such is a finite resource. However, as with any metal ore, the absolute quantity of the metal available is irrelevant, it's the quality of the ore that matters. Below a certain concentration the recovery of uranium will take more energy than it produces. The most productive uranium ores contain 1,000 to 20,000 parts per million of uranium (ppmU), the cut-off value, at which the energy used to extract uranium from the ore exceeds the energy produced from the nuclear plant, at around 20ppmU. Even with advances in processing and reactor design this is unlikely to fall far below 10ppmU. This puts a limitation on the theoretical size of the uranium resource because a number of the potential sources fall below this level and makes other potential sources, such as igneous rocks, which have concentrations of uranium of around 4ppmU and sea water, also quoted as a future source of uranium, with an average uranium content of 0.003ppmU, look rather pointless - take a bow James Lovelock. Whilst we're not at the point at which the viable ores (in terms of energy produced from fissioning a given quantity of uranium being greater than the energy required to produce the uranium) are exhausted, the proposed massive expansion in nuclear generating capacity would ensure that this point would soon be reached. Figures have been quoted of anywhere between 72 and 12 years - hardly sustainable.
Don't be taken in by anyone who suggests that Fast Breeder Reactors will enable nuclear power to continue indefinitely either. Scientists in the USA realised back in the 1950's that viable uranium ores would quickly become exhausted if everyone switched to nuclear power - as seemed likely at the time - and so developed the Fast Breeder reactor. This uses a small quantity of Uranium 235 to 'breed' Plutonium from Uranium 238, the Plutonium then being 'burnt' (fissioned) in a reactor. In theory, a reactor would be able to produce enough Plutonium to fuel another reactor after about 25 years of operation.
However, in spite of 50 years of trying, no one has been able to get a Fast Breeder Reactor to work reliably for any length of time. Water cannot be used as a coolant as it slows down the 'Fast' neutrons the process relies on and so coolants such as Sodium metal must be used, the heat from which has to be transferred to water to make steam to drive turbines. Anyone who did chemistry at school knows that Sodium and water don't mix, tons of Sodium at 900oC and water don't really bear thinking about - sodium leaks and fires caused the closure of the Superphenix fast breeder reactor in France and the Monjuc reactor in Japan. The Germans also tried to get one to work and failed.
On top of all of this Fast Breeder Reactor require large re-processing facilities to separate the Plutonium from the unburnt Uranium and other radioactive nasties with consequent huge energy inputs and CO2 outputs and security risks. You might also hear about reactors using abundant Thorium as a fuel. These require a form of breeder reactor to work, with all of the problems mentioned above, plus the fact that no one has convincingly demonstrated that the proposed cycle will work at all.
Other niggling issues that refuse to go away no matter how much spin is applied include:
Even discounting the resultant protests, planning enquiries and general wailing and gnashing of teeth that would accompany any proposed nuclear power stations, the time scales involved make nuclear power a non-starter. Then minimum of ten years it would take to construct any proposed power stations is too long, solutions to climate change are needed now – only renewable energy projects and energy conservation measure can deliver the necessary cuts in time.
Where to build them?
Hostility to construction and the need for extensive infrastructure to support nuclear power plants, such as roads, powerlines, access to a skilled work force and access to sufficient cooling water means that the only viable locations are on the coast next to existing nuclear power stations. However rising sea levels are putting many of these sites at risk...
The UK has no Uranium reserves of it's own. Relying on imported Uranium makes us as vulnerable as we are at the moment using imported oil and gas. Renewable energy is an indigenous resource - the UK has a greater potential for wind power than any other country in Europe.
They're huge, prestigious, terrorist targets. Yes the reactor core may be able to withstand an impact from a 747 travelling at twice the speed of sound or whatever figures are used to reassure the public, but what about the waste storage ponds, coolant inlets and control rooms? Even if an attack only destroyed the power lines, large areas of the country could be blacked out. Renewables are, by their very nature, a dispersed source of energy. Blowing up one wind turbine will have much less impact on the UK's power supply.
Any expansion of nuclear power generation in the UK will lead to a consequent increase in overt and covert security to guard the facilities against risk of attack with a consequent increase in the monitoring of the population as a whole.
Obviously loads of issues surrounding this and it has the potential to completely undermine this article's first paragraph regarding the safety of nuclear power ' how we can say any part of the Earth is geologically stable when we live on one of the most geologically active bodies in the solar system? 5,000 years ago the English Channel didn’t exist...
Given all of the above, aren't energy conservation, energy efficiency and renewable energy investment the most logical choices, leaving nuclear power as yesterday's also ran:
Nuclear power, a stupid way to boil water...!