Friday, January 13, 2017

Peak Uranium: the uncertain future of nuclear energy

 
Alice Friedmann recently posted on her blog "Energy Skeptic" a summary of the discussion on nuclear energy from my book "Extracted" (Chelsea Green, 2014). It is a well-done summary that I am reproducing here. Note that the text below mixes some of the considerations of the main text (written by me) and of one of the "glimpses"; that were written by other authors. The glimpse that reports the results of a model of future uranium production was written by Michael Dittmar. He told me in a recent mail exchange that his model seems to be doing pretty well more than two years after its results were published in "Extracted". (U.B.)

Peak Uranium by Ugo Bardi from "Extracted: How the Quest for Mineral Wealth Is Plundering the Planet"


Figure 1. cumulative uranium consumption by IPCC model 2015-2100 versus measured and inferred Uranium resources

[ Figure 1 shows that the next IPCC report counts very much on nuclear power to keep warming below 2.5 C.  The black line represents how many million tonnes of reasonably and inferred resources under $260 per kg remain (2016 IAEA redbook). Clearly most of the IPCC models are unrealistic.  The IPCC greatly exaggerates the amount of oil and coal reserves as well. Source: David Hughes (private communication)


This is an extract of Ugo Bardi’s must read “Extracted” about the limits of production of uranium. Many well-meaning citizens favor nuclear power because it doesn’t emit greenhouse gases.  The problem is that the Achilles heel of civilization is our dependency on trucks of all kinds, which run on diesel fuel because diesel engines transformed our civilization with their ability to do heavy work better than steam, gasoline, or any other kind of engine.  Trucks are required to keep the supply chains going that every person and business on earth require, from food to the materials and construction of the roads they run on, as well as mining, agriculture, construction trucks, logging etc. 

Nuclear power plants are not a solution, since trucks can’t run on electricity, so anything that generates electricity is not a solution, nor is it likely that the electric grid can ever be 100% renewable (read “When trucks stop running”, this can’t be explained in a sound-bite).  And we certainly aren’t going to be able to replace a billion trucks and equipment with diesel engines by the time the energy crunch hits with something else, there is nothing else.


Alice Friedemann   www.energyskeptic.com  author of “When Trucks Stop Running: Energy and the Future of Transportation”, 2015, Springer and “Crunch! Whole Grain Artisan Chips and Crackers”. Podcasts: Practical Prepping, KunstlerCast 253, KunstlerCast278, Peak Prosperity , XX2 report ]

Bardi, Ugo. 2014. Extracted: How the Quest for Mineral Wealth Is Plundering the Planet. Chelsea Green Publishing.

Although there is a rebirth of interest in nuclear energy, there is still a basic problem: uranium is a mineral resource that exists in finite amounts.

Even as early as the 1950s it was clear that the known uranium resources were not sufficient to fuel the “atomic age” for a period longer than a few decades.

That gave rise to the idea of “breeding” fissile plutonium fuel from the more abundant, non-fissile isotope 238 of uranium. It was a very ambitious idea: fuel the industrial system with an element that doesn’t exist in measurable amounts on Earth but would be created by humans expressly for their own purposes. The concept gave rise to dreams of a plutonium-based economy. This ambitious plan was never really put into practice, though, at least not in the form that was envisioned in the 1950s and ’60s. Several attempts were made to build breeder reactors in the 1970s, but the technology was found to be expensive, difficult to manage, and prone to failure. Besides, it posed unsolvable strategic problems in terms of the proliferation of fissile materials that could be used to build atomic weapons. The idea was thoroughly abandoned in the 1970s, when the US Senate enacted a law that forbade the reprocessing of spent nuclear fuel.

A similar fate was encountered by another idea that involved “breeding” a nuclear fuel from a naturally existing element—thorium. The concept involved transforming the 232 isotope of thorium into the fissile 233 isotope of uranium, which then could be used as fuel for a nuclear reactor (or for nuclear warheads). The idea was discussed at length during the heydays of the nuclear industry, and it is still discussed today; but so far, nothing has come out of it and the nuclear industry is still based on mineral uranium as fuel.

Today, the production of uranium from mines is insufficient to fuel the existing nuclear reactors. The gap between supply and demand for mineral uranium has been as large as almost 50% from 1995 to 2005, though gradually reduced the past few years.

The U.S. mined 370,000 metric tons the past 50 years, peaking in 1981 at 17,000 tons/year.  Europe peaked in the 1990s after extracting 460,000 tons.  Today nearly all of the 21,000 ton/year needed to keep European nuclear plants operating is imported.

The European mining cycle allows us to determine how much of the originally estimated uranium reserves could be extracted versus what actually happened before it cost too much to continue. Remarkably in all countries where mining has stopped it did so at well below initial estimates (50 to 70%). Therefore it’s likely ultimate production in South Africa and the United States can be predicted as well.
Table 1. The European mining cycle allows us to determine how much of the originally estimated uranium reserves could be extracted versus what actually happened before it cost too much to continue. Remarkably in all countries where mining has stopped it did so at well below initial estimates (50 to 70%). Therefore it’s likely ultimate production in South Africa and the United States can be predicted as well.

The Soviet Union and Canada each mined 450,000 tons. By 2010 global cumulative production was 2.5 million tons.  Of this, 2 million tons has been used, and the military had most of the remaining half a million tons.

The most recent data available show that mineral uranium accounts now for about 80% of the demand.  The gap is filled by uranium recovered from the stockpiles of the military industry and from the dismantling of old nuclear warheads.

This turning of swords into plows is surely a good idea, but old nuclear weapons and military stocks are a finite resource and cannot be seen as a definitive solution to the problem of insufficient supply. With the present stasis in uranium demand, it is possible that the production gap will be closed in a decade or so by increased mineral production. However, prospects are uncertain, as explained in “The End of Cheap Uranium.” In particular, if nuclear energy were to see a worldwide expansion, it is hard to see how mineral production could satisfy the increasing uranium demand, given the gigantic investments that would be needed, which are unlikely to be possible in the present economically challenging times.

At the same time, the effects of the 2011 incident at the Fukushima nuclear power plant are likely to negatively affect the prospects of growth for nuclear energy production, and with the concomitant reduced demand for uranium, the surviving reactors may have sufficient fuel to remain in operation for several decades.

It’s true that there are large quantities of uranium in the Earth’s crust, but there are limited numbers of deposits that are concentrated enough to be profitably mined. If we tried to extract those less concentrated deposits, the mining process would require far more energy than the mined uranium could ultimately produced [negative EROI].

Modeling Future Uranium Supplies
Uranium supply and demand to 2030
Table 2. Uranium supply and demand to 2030

Michael Dittmar used historical data for countries and single mines, to create a model that projected how much uranium will likely be extracted from existing reserves in the years to come. The model is purely empirical and is based on the assumption that mining companies, when planning the extraction profile of a deposit, project their operations to coincide with the average lifetime of the expensive equipment and infrastructure it takes to mine uranium—about a decade.

Gradually the extraction becomes more expensive as some equipment has to be replaced and the least costly resources are mined. As a consequence, both extraction and profits decline. Eventually, the company stops exploiting the deposit and the mine closes. The model depends on both geological and economic constraints, but the fact that it has turned out to be valid for so many past cases shows that it is a good approximation of reality.
This said, the model assumes the following points:
  • Mine operators plan to operate the mine at a nearly constant production level on the basis of detailed geological studies and to manage extraction so that the plateau can be sustained for approximately 10 years.
  • The total amount of extractable uranium is approximately the achieved (or planned) annual plateau value multiplied by 10.
Applying this model to well-documented mines in Canada and Australia, we arrive at amazingly correct results. For instance, in one case, the model predicted a total production of 319 ± 24 kilotons, which was very close to the 310 kilotons actually produced. So we can be reasonably confident that it can be applied to today’s larger currently operating and planned uranium mines.

Considering that the achieved plateau production from past operations was usually smaller than the one planned, this model probably overestimates the future production.

Table 2 summarizes the model’s predictions for future uranium production, comparing those findings against forecasts from other groups and against two different potential future nuclear scenarios.

As you can see, the forecasts obtained by this model indicate substantial supply constraints in the coming decades—a considerably different picture from that presented by the other models, which predict larger supplies.

The WNA’s 2009 forecast differs from our model mainly by assuming that existing and future mines will have a lifetime of at least 20 years. As a result, the WNA predicts a production peak of 85 kilotons/year around the year 2025, about 10 years later than in the present model, followed by a steep decline to about 70 kilotons/year in 2030. Despite being relatively optimistic, the forecast by the WNA shows that the uranium production in 2030 would not be higher than it is now. In any case, the long deposit lifetime in the WNA model is inconsistent with the data from past uranium mines. The 2006 estimate from the EWG was based on the Red Book 2005 RAR (reasonably assured resources) and IR (inferred resources) numbers. The EWG calculated an upper production limit based on the assumption that extraction can be increased according to demand until half of the RAR or at most half of the sum of the RAR and IR resources are used. That led the group to estimate a production peak around the year 2025.

Assuming all planned uranium mines are opened, annual mining will increase from 54,000 tons/year to a maximum of 58 (+ or – 4) thousand tons/year in 2015. [ Bardi wrote this before 2013 and 2014 figures were known. 2013 was 59,673 (highest total) and 56,252 in 2014.]

Declining uranium production will make it impossible to obtain a significant increase in electrical power from nuclear plants in the coming decades.

6 comments:

  1. Wath about the so called fast Breeders. BN-800?

    http://fissilematerials.org/blog/2015/12/russian_bn-800_fast_breed.html

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  2. JimK has left a new comment on your post "Peak Uranium: the future of nuclear energy":

    Erased by mistake. Reposting.

    A useful review of uranium resources... I haven't found a link to a free version, though! https://www.scientificamerican.com/article/world-uranium-resources/

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  3. Alvin Weinberg at Oak Ridge had a thorium molten salt reactor running, but the AEC (now DOE) didn't like it because it didn't mesh well with the existing nuclear fuel infrastructure, which was intended to also provide uranium and plutonium for weapons. Had we developed this technology early on, it might have become popular and able to displace U-235 as the main fissile fuel. I think we're beyond the point of being able to turn it into a viable industry, due to depletion of oil and other resources. I'm no nuclear engineer, but I'm guessing that a crash program to bring thorium reactors to market could take 20-30 years.

    This is a movie by a thorium evangelist.
    https://www.youtube.com/watch?v=0BybPPIMuQQ

    A group of subatomic particle physicists, one of whom lives near me, have proposed creating accelerator-driven subcritical molten salt breeder reactors, which can consume a wide variety of heavy elements, including U-238 and thorium. An accelerator is used to hit a spalting target (Bi or W) with protons to create a neutron source, which is used to enrich then split fuel a little at a time. As long as the fuel mix is subcritical, the rector can be modulated or shut down by turning off the beam. Our huge stockpile of depleted uranium and spent conventional fuel rods would last a long time, requiring no new mining for many years.
    http://public.muonsinc.com/Projects/AcceleratorDrivenSubcriticalReactors.aspx

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    Replies
    1. Jon, interesting choice of a pro-thorium film. Almost any of the films published by Kirk Thorensen would do a far better job of introducing the topic to a layman. Here are three:
      https://www.ted.com/talks kirk_sorensen_thorium_an_alternative_nuclear_fuel
      https://www.youtube.com/watch?v=MCyJ3bq8FQw
      http://energyfromthorium.com/

      Hugo,
      Your analysis of the uranium fuel cycle and its inevitable confrontation with the fact of finite resources is of course correct. However your dismissal of the thorium fuel cycle and lumping the thorium-fueled molten salt reactor in with the uranium fueled pressure water reactor as "nuclear energy" is a common but misleading.

      1000++ year supply of thorium -- a bi-product of rare earth mining -- a mining operation driven by electric battery technology demand-- Thorium ores with a denser concentration than uranium ores- common element in everything from beach sand to the fly ash remaining from burning coal. And that is only the supply side of the picture.

      A few outstanding advantages:

      Automatic cold shutdown with no mechanical or human operator input needed. Poor source of weapons grade uranium. 5% of the total waste volume, and that with half lives of -300 years instead of tens of thousands as in the case of plutonium. Potential for assembly line plant manufacture with plant costs 1/10 that of conventional uranium-fueled light water reactors. Etc.

      If the apparent advantages of the Liquid Fluoride Thorium Reactor are correct, the coming scarcity of uranium ores is a problem about as critical as the scarcity of Model T Fords.



      Delete
  4. An academic in Britain, Dave Toke,writes on energy matters http://realfeed-intariffs.blogspot.co.uk/2017/01/how-scotland-could-double-amount-of-low.html#comment-form

    He is now located in Scotland where non-nuclear policy is likely to be increasingly different from that in England. Dr Toke has recently written a paper.
    Quote: "This report argues that the costs of delivering the UK s low carbon programme could be reduced substantially if the Scottish Government were given powers to fund its own renewable energy programme. This could be done by giving the Scottish Government control to spend money that would otherwise be added to Scottish electricity consumer bills to fund the Hinkley Point C (HPC) nuclear power plant (and any other new nuclear plant)."

    I commented with a link to this (Ugo's) blog. Dr Toke and Professor Elliot have a wide range of contacts among UK energy professionals.

    best
    Phil

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  5. I wrote a post concerning how technical solutions (like various nuclear technologies) are just one part of the capacity needed for change.

    You can read about the Technical, Material and Social capacity needed for change—as well as a recipe for pie crust, in We have enough Ideas (or, No pie for you.)

    ReplyDelete

Who

Ugo Bardi is a member of the Club of Rome and the author of "Extracted: how the quest for mineral resources is plundering the Planet" (Chelsea Green 2014)