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  1. Hi Rod

    I enjoyed the conversation but in particular your comments about the possibility of achieve break-even conversion on the Uranium-Plutonium cycle. Charles Barton disagree expressing the common view that such breeding was only possible in the fast spectrum. I found some information about a possible light water breeder using the U-Pu cycle rather than the original LWBR on the U233-Th232 cycle. As far as I understand it, using the epithermal spectrum Pu 241 is a good fissile fuel so using this in combination with U238 to Pu 239 successful breeding may be established. What do you think, I am very interested in discovering more about achiveing break even in the epithermal spectrum.

    Look forward to your response. Great show. Alex

  2. Alex – Glad you enjoyed the show. There has indeed been a good deal of intellectual work done on achieving a breeding ratio of close to or even exceeding 1.0 using uranium-plutonium fuels in an epithermal spectrum. The key is in selecting just how moderated the core is – if you squeeze out some moderation and add more fuel material, you can achieve break even.

    The Japanese have done some good work in this area. Here is one example paper:


    One of the real keys here is to realize that there is no urgent need to produce a lot of excess fissile material. As we modify reactors to approach 1.0, the depletion rate of fissile material in the world slows down. If there is a finite amount of fissile material accessible, reactors with a conversion ratio close to 1 will move the resource depletion date way out to the right. That gives us plenty of time to develop other sources of competitive power that will enable human prosperity for millennia.

  3. Nice discussion, I enjoyed it. In the discussion Dan refers to an EIA report regarding power uprates. He says that the 2009 EIA report estimates that 20% (20GW) will come from uprating of existing plants. I looked and searched but I couldn’t find a report that states this, can you provide a reference to this for me? The NRC maximum available uprates are the extended power uprates, which provide up to 20% addtional power. The largest uprates, 20%, have only occurred in BWRs, which is approximately 1/3 of the US fleet. Therefore, I don’t see how 20GW could be added and hence my interest in the reference to the EIA report. Thanks.

  4. Thanks for the links Rod, Good reading. Hope these concepts get developed because many people I am sure would like to see us really getting into taking full advantage of the heavy metal’s energy density. Once this is done one a large scale then humanities energy requirements are effectively limitless. Alex

  5. Getting a loan guarantee from the government sounds a lot like getting a loan from a bank. In order to get the loan, they first need to prove they don’t need it.

  6. Here’s a link to an interesting in-depth presentation of the “Travelling Wave Reactor” concept presented by John Gilleland chief scientist with TerraPower, LLC:


    If it works as advertised it could be a revolutionary “game changer” to such a degree that it may frighten off prospective utilities from committing to conventional fission project outlays.

    Jess: perhaps Dan Yurman was referring to the potential power uprates made possible by annular fuel cores according to studies at MIT (50% for PWRs, ~23% for BWRs):


    and here


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