Sunday, 20 March 2016

The myth of peak uranium

"If the Nuclear Energy Agency (NEA) has accurately estimated the planet's economically accessible uranium resources, reactors could run more than 200 years at current rates of consumption."
-- "How long will the world's uranium supplies last?", Scientific American, 2009, by Steve Fetter
"There is an estimated forty trillion tonnes of uranium in the earth's crust."
-- Till & Chang, 2011

Surely both of these quotations can't be right. Because the energy we can get from uranium is 10 million times what we can get from fossil fuel. It's estimated there is about 57 zettajoule (ZJ) of fossil fuel on earth. Or 1.36 million MTOE = 1.36 trillion tonnes of oil equivalent (TOE). In energy terms: there is about 1.3 billion times more fission energy available in the earth's crust than fossil fuel energy.

  • Fetter only considered the current fuel cycle. Only 3.5% of fuel is used in the water-moderated reactor cycle, leaving 96.5% of the potential untapped. On the way to making the fuel, most of the uranium was left out - as depleted uranium (DU). Over 8 times more uranium becomes DU than fuel. Uranium-238 to plutonium-239 breeder reactors can use all uranium found in both spent fuel and DU.
  • Include thorium breeder reactors and there's thousands of times more available fuel. A lot of the thorium has already been mined and is just sitting around in tailing heaps waiting for us to do something useful with it. There's about 3.5 times more thorium in the earth's crust than uranium. About 140 trillion tonnes of it.
  • There's more uranium than Fetter wrote about.
    • We will find more uranium deposits by just looking for them. I've been told to expect peak oil for at least 35 years now. Every year we find more oil. We will also find a lot more uranium. For example the IAEA "identified resources" saw uranium increase 0.7m tonnes in just 4 years - from 4.7m tonnes (2005) to 5.4m tonnes (2009).
    • There are vast uranium deposits in the world's oceans : 4500 million tonnes of it - about 800 times more than Fetter accounted for. We already have technology to extract this (at about $600 per kg).
    • There's more uranium in lower quality ore deposits: Charles Till and Yoon Il Chang discuss uranium resources in pages 91 to 95 of 'Plentiful Energy' (pdf book)

Ref: Plentiful Energy - The story of the integral fast reactor, 2011, by , pages: 91 to 95.

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