This is an easy to read 56-page primer on how nuclear reactors work, how ore is mined, nuclear fuel created, why there’s likely to be a supply crunch, and much more. I’ve extracted a small part of this article and often rephrased some of it. Fleming doesn’t have many (high-quality) citations, so I’ve left out most of what he wrote since I’m not sure if he’s right about various matters (see the discussion at the end of this 2008 theoilddrum article by Fleming)
David Fleming . 2007. The Lean Guide to Nuclear Energy. A Life-Cycle in Trouble. www.theleaneconomyconnection.net
Nuclear power is a source of high-level waste which has to be sequestered. Every stage in the process produces waste, including the mining and leaching processes, the milling, the enrichment and the decommissioning. It is very expensive.
Deep reductions in travel and transport can be expected to come about rapidly and brutally as the oil market breaks down [from declining oil production, making disposal of the wastes less likely].
Nuclear energy relies on the existence of a fully powered-up grid system into which it can feed its output of electricity – but the grid itself is mainly powered by the electricity from mainly coal and gas-fueled power stations, so if coal or gas supplies were to be interrupted, the grid would (at least partially) close down, along with the nuclear reactors that feed into it;
Nuclear energy inevitably brings a sense of reassurance that, in the end, the technical fix will save us. Which it can’t [since electricity doesn’t solve the liquid fuels crisis at hand, since mining and long-haul trucks, tractors, harvesters, and billions of other diesel powered equipment can’t be run on fuel cells or batteries].
The nuclear industry should focus on finding solutions to the whole of its waste problem before it becomes too late to do so. And hold it right there, because this is perhaps the moment to think about what “too late” might mean. Despite the emphasis placed on oil depletion in this booklet, it is climate change that may well set the final date for completion of the massive and non-negotiable task of dealing with nuclear waste. Many reactors are in low-lying areas in the path of rising seas; and many of the storage ponds, crowded with high-level waste, are close by. Estimated dates for steep rises in sea levels are constantly being brought forward (as of 2014 the latest projection is 1 meter by 2100 made much worse by storm surges best case, worst case is Antarctic or Greenland ice sheets slip off the land into the ocean).
With an angry climate, and whole populations on the move, it will be hard to find the energy, the funds, the skills and the orderly planning needed for a massive program of waste disposal – or even moving waste out of the way of rising tides. When outages in gas supplies lead to break down in electricity supplies, the electrical-powered cooling systems that cool high-level waste will stop working.
It will also be hard to stop ragged armies, scrambling for somewhere to live, looting spent fuel rods from unguarded dumps, attaching them to conventional explosives, and being prepared to use them. All this will have to be dealt-with, and at speed. There may be no time to wait for reactor cores and high-level wastes to cool down.
The task of making those wastes safe should be an unconditional priority, equal to that of confronting climate change itself. The default-strategy of seeding the world with radioactive time-bombs which will pollute the oceans and detonate at random intervals for thousands of years into the future, whether there are any human beings around to care about it or not, should be recognized as off any scale calibrated in terms other than dementia. Nuclear power is an energy source that causes trouble far beyond the scale of the energy it produces. It is a distraction from the need to face up to the coming energy gap.
How reactors work
Nuclear fission uses Uranium-235, an isotope of uranium that splits in half when struck by a neutron, producing more neutrons resulting in a chain reaction that produces lots of energy. The process is controlled by a moderator consisting of water or graphite, which speeds the reaction up, and by neutron-absorbing boron control rods, which slow it down. Eventually the uranium gets clogged with radioactive impurities such as the barium and krypton from uranium-235 decays, “transuranic” elements such as americium and neptunium, and much of the uranium-235 itself gets used up. It takes a year or two for this to happen, and then the fuel elements have to be removed, and fresh ones inserted. The spent fuel elements are very hot and radioactive (stand nearby for a second and you’re dead). In Europe the spent fuel is sometimes recycled (reprocessed), to extract the remaining uranium and plutonium and use them again, although you don’t get as much fuel back as you started with, the bulk of impurities still has to be disposed of, and other scientists believe this has a negative EROEI. Very few nations have anywhere safe to put it to keep future generations from harming themselves over the next billion years (the half-life of U-238, one of the main items of waste, is about 4.5 billion years).
The steps to get electricity from uranium
1. Mine and mill ore. Although uranium is found all over the world, only a few places have enough concentrated uranium ores (.01-.2%) to mine: Australia, Kazakhstan, Canada, South Africa, Namibia, Brazil, Russia, the USA, and Uzbekistan in mines up to 800 feet deep. Mines are injected and drenched in in tons of sulfuric acid, nitric acid, ammonia, and other chemicals and pumped up again after 3-25 years, yielding about a quarter of the uranium from the treated rocks and depositing unknown amounts of radioactive and toxic metals into the local environment. You need to grind up 1,000 tons of .1% ore to get 1 ton of yellow oxide and 999 tons of waste, both of which are radioactive from uranium-238 and 13 decay products. The waste takes up much more space after it has been mined, where wind and water can take radioactive waste far away. Properly cleaning it up would take 4 times the energy to mine the ore, so it seldom happens.
2. Preparing the fuel. The uranium oxide must now be enriched to concentrate U-235 to 3.5%, resulting in even more nasty, toxic, scary waste that isn’t properly disposed of. One of the wastes from this process is plutonium, which can be used to make nuclear bombs.
3. Generation. The fuel can now be used to produce heat to raise the steam to generate electricity. When the fuel rods are spent they must cool off to allow the isotopes to decay from 10 to 100 years before they can be disposed of elsewhere. The ponds need a reliable electricity supply to keep them stirred and topped up with water to stop the radioactive fuel elements drying out and catching fire. Then robots need to pack the wastes into lead, steel, and pure electrolytic copper, and put into giant geological repositories considered to be stable. There will never be an ideal way to store waste which will be radioactive for a thousand centuries or more and, whatever option is chosen, it will require a lot of energy.
Human Error. The consequences of a serious accident would make nuclear power an un-insurable risk. The nuclear industry has good safety systems but is not immune to accidents. The work is routine, requiring workers to cope with long periods of tedium punctuated by the unexpected, along with “normality-creep” as anomalies become familiar. The hazards were noted in the mid-1990s by a senior nuclear engineer working for the U.S. Nuclear Regulatory Commission: “I believe in nuclear power but after seeing the NRC in action, I’m convinced a serious accident is not just likely, but inevitable… They’re asleep at the wheel.” The Nuclear Regulatory Commission estimates the probability of meltdown in the U.S. over 20 years is 15 to 45%. The risk never goes away.
4. Reactors last 30-40 years [but are being renewed for another 20 anyhow] but produce electricity at full power for no more than 24 years. During their lifetimes, reactors have to be maintained and (at least once) thoroughly refurbished; eventually, corrosion and intense radioactivity make them impossible to repair. At that point they must be taken apart and disposed of, resulting in at least a thousand cubic meters of high-level waste. After a cooling-off period which may be as much as 50-100 years, the reactor has to be dismantled and cut into small pieces to be packed in containers for final disposal. The total energy required for decommissioning has been estimated at approximately 50 percent more than the energy used in the original construction.
Every stage in the life-cycle of nuclear fission uses energy, and most of this energy is derived from fossil fuels. Since we’re waiting for high-level waste to cool off before dismantling plants, the emissions look better now than they will in the future. And as ores get less concentrated, the carbon dioxide from mining will consume more fossil fuels and emit even more greenhouse gases.
Nuclear power may have a negative EROEI & Peak Uranium
Deposits are often at great depth, requiring the removal of massive overburden, or the development of very deep underground mines, require more energy to mine the resource than is required by the shallower mines now being exploited.
Water problems can reduce EROEI. You can have too little water (it is needed as part of the process of deriving uranium oxide from the ore) or too much (it can cause flooding). Some of the more promising mines have big water problems.
How much uranium with a positive EROEI is left? The Energy Watch group predicts Peak Uranium between 2020-2035. Michael Dittmar at the Institute of Particle Physics predicts Peak Uranium will happen in 2015. The 2005 OECD Nuclear Energy Agency (NEA) and the International Atomic Energy Agency (IAEA) suggested a 70 year supply at the current price.
Every year 65,000 tons of uranium are consumed in reactors worldwide. About 40,000 tons are supplied from uranium mines (which are declining in output), 10,000 tons comes from Russian nuclear weapons (contract for this expires in 2013), and 15,000 tons comes from inventories which won’t last much longer.
So the only hope to keep enough uranium in production for existing reactors is more mining. Several medium-sized producers have maintained or increased output the past few years in Kazakhstan, Namibia, Niger, Russia, America and Canada.
But the biggest hope for more uranium is from the Cigar Lake mine, but after catastrophic flooding in 2006, and again in 2008, it wasn’t until spring of 2014 that the mine finally started processing uranium ore. The other big hope was the Olympic Dam in Australia, which has the largest known single deposit of uranium in the world (but it’s very low-grade, with an average of .03%, and only economic because uranium is a byproduct of gold, silver, and copper mining.
Fleming predicts that before 2019 some nuclear reactors will have to shut down due to a lack of fuel.
Fleming goes to great lengths to explain why nuclear power won’t end up having a positive net energy in the future, mainly due to the tremendous amount of energy that will be needed to safely store the wastes that have been building up since the industry started back in the 1950s. (I believe it is highly unlikely we will ever store any of this waste because as oil declines, which 99% of transportation is fueled by, people will want to use oil to grow and transport food, pump drinking water, treat sewage, and so on — safely storing nuclear waste will be at the bottom of the list. This is an outrageous crime: we will poison millions of generations of our descendants, and add to the growing pile of dangers that might drive us extinct).
Fleming demolishes Lovelocks’ proposal to use nuclear power to get ourselves out of the energy and climate change mess. First he shows why Lovelock’s idea of getting uranium from granite won’t work – it’s such a low concentration (.0004%) and for a 1 GW plant, you’d need 100 million tons of granite ore requiring 650 petajoules to extract, yet the energy delivered from the uranium would only be 26 petajoules. The same negative energy return true of uranium from sea water.
Lovelock also urges that we have a readily-available stock of fuel in the plutonium that has been accumulated from the reactors that are shortly to be decommissioned. But this won’t work for many reasons, including that it’s never been attempted in reactors like those we have now. If Lovelock means for us to use a breeder reactor, that has huge problems as well (including that we don’t know how to do this safely yet). There are 3 fast-breeder reactors in the world: Beloyarsk-3 in Russia, Monju in Japan and Phénix in France; Monju and Phénix have long been out of operation; Beloyarsk is still operating, but it has never bred. Getting the plutonium to breed involves 3 processes that, like breeder reactors, have never been done at a commercial scale. You end up with many nasty radioactive mixtures that clog up and corrode equipment. Even if you could figure out how to do build breeder reactors in 30 years and built 80 in 2045, it would take another 40 years for each breeder to produce enough plutonium to replace itself and start up another nuclear plant. By 2085 we will be deep into oil depletion, yet only have 160 breeder reactors. And that is all we will have, because the uranium-235 reactors we have now will be out of fuel by then.
It’s impossible to prevent accidents at a breeder reactor
A meltdown is nothing compared to the explosion of a breeder reactor, which is basically a large nuclear bomb in a major accident. If you designed a system that couldn’t fail, it would be so expensive you’d have to build an enormous breeder reactor to justify the cost, but such a large reactor would have such a huge dome that there is no material to give it enough structural strength to survive a major accident. You could try to make the defense system even more complex, but then the defense system would be more problem-prone than the breeder reactor itself. A study for the nuclear industry in Japan concludes: “A successful commercial breeder reactor must have 3 attributes: it must breed, it must be economical, and it must be safe. Although any one or two of these attributes can be achieved in isolation by proper design, the laws of physics apparently make it impossible to achieve all three simultaneously, no matter how clever the design.”
(A truly ridiculous idea — see Peak Phosphorous). Phosphate reserves are likely to last at most for 70 years and they are essential for growing food. They’re also a poor source because they have very low concentrations of uranium. Extracting uranium is difficult, and results in greenhouse gases — the solvents used include toxic organophosphate compounds that result in organofluorophosphorus and greenhouse gases in the form of fluorohydrocarbons.
David Fleming has an MA (History) from Oxford, an MBA from Cranfield and an MSc and PhD (Economics) from Birkbeck College, University of London. He has worked in industry, the financial services and environmental consultancy, and is a former Chairman of the Soil Association. He designed the system of Tradable Energy Quotas (TEQs), (aka Domestic Tradable Quotas and Personal Carbon Allowances), in 1996, and his booklet about them, Energy and the Common Purpose, now in its third edition in this series, was first published 2005. His Lean Logic: The Book of Environmental Manners is forthcoming.