Indefatigable ignorance is hard to deal with.  Maybe the numbers about the money will do the trick for some that still have a bit of reason.  For the rest of us it’s a difference of a thousand times of earnings verses expense.

The topic is used nuclear fuel.

Next week scientists from around the globe gather in Toronto to discuss the best ways of burying nuclear waste for tens of thousands of years.   This idea is a huge waste of a valuable resource.  The costs for transport, storage, oversight, guards, security, facilities and the chance for a bit to escape into the hands of murderers on vast scale are going to be huge – surely billions, more likely tens of billions.

The ideas on how to reuse and extract the energy have been brewing for over 50 years and better ones keep popping up.

Retired Canadian University of Toronto professor emeritus of biophysics Peter Ottensmeyer is trying to bring thinking on ordinary nuclear waste into the 21st century.  Ottensmeyer points out there is 134 times the amount of energy available from used nuclear fuel than taken in the first use.  He estimates the value of the potential electricity to be in the trillions of dollars.

Do we want to throw it away at great expense or put it to work?

Used fuel is packed full of heavy atoms.  These atoms are not going to fission without some help.  The fuel after re-use will also lose its radioactivity much more quickly, from hundreds of thousands to a more responsible few hundred years.  Plus some of the heavy atoms that are fissioned in a re-use process are transformed into valuable platinum group metals.

The hard number is once around fission process leaves a residue of highly radioactive materials that emit harmful radiation for 400,000 years.

Ottensmeyer suggests a fast neutron reactor.  In one of those the heavy atoms decay to the safe to handle level of natural uranium in less than 300 years.

Fast Neutron Reactor Simple Diagram. Click image for the largest view.

Fast neutron reactors have been in use for decades, but not on a commercial scale.  ‘Fast’ neutron reactors are different than the ‘slow’ neutron reactors.

Natural uranium contains mostly U-238, with traces – less than 1 per cent – of the lighter version, called U-235.  Today’s reactors focus on the U-235, which is split when it collides with neutrons emitted by the uranium.  When neutrons are created in a reactor, they travel fast, and generally bounce off the U-235 without splitting it.  Various techniques slow the neutrons down so they are able to split U-235 atoms, releasing vast amounts of heat that’s used to produce steam, and so power electric generators.

The U-238 that makes up most of the reactor fuel is not split, and not used, although the reaction does cause it to mutate into heavier elements, including the dreaded plutonium. The process leaves a use fuel cache of highly radioactive materials that emits harmful radiation for the noted 4,000 centuries.

Ottensmeyer points out simply that the slow neutrons could be kept going faster with different cooling or moderators in a reactor.  Sodium or a mixture of the heavy metals lead and bismuth work because they’re denser moderators and keep the neutrons bouncing around at high speeds, instead of slowing down, as neutrons in water-moderated reactors do.

The matter before the energy users is whether to spend billions or make back trillions of dollars.  The fundamentals haven’t been lost on the industry.  GE and Hitachi are developing a sodium-moderated fast neutron reactor called the Prism – that’s in consideration in the U.K. as a method of using its excess plutonium.

Building an elaborate underground depository to simply store the waste for thousands of millennia will cost $20, $30 or more billions and cost an uncalculated annual expense to be paid by electricity users.

Or choose to use a resource and wind up with an abundance of low cost electricity without much of the risk and time at risk.

Keep in mind, once the fuel is re-used, the precious and other elements extracted and the radioactivity subsides, you can put the uranium back in a fast reactor and use it over again.

Now you have a working knowledge better than most all the journalists in the media stirring up the ill informed.  Indefatigable ignorance depends on radiation scares and other oddities tp keep the special interest against nuclear power going.

One way or another the used fuel at hand will get handled by an expensive loss of the resource or investment to recover a huge reserve of energy and get to a faster route for long term safety and perhaps recycled heavy atoms.


3 Comments so far

  1. Matt Musson on October 4, 2012 7:15 AM

    I cannot help thinking that a subcritical nuclear reactor that takes in neutrons from a linear accellerator is a much safer and easier way to burn spent nuclear fuel and waste.

  2. Jagdish on October 4, 2012 11:36 PM

    Te fast neutron reactors and also the Molten Salt fueled reactors (including the LFTR) are in general discussion these days. It is possible have the benefits of both in the Fast Spectrum Molten Salt Reactors.

  3. praos on October 7, 2012 4:01 AM

    Ottensmeyer is right, but that’s nothing new. The problem with nuc power is, however, that it’s too good. Development of nukes was stopped because there was no market for their immense power. The “waste” is a waste only because there is lack of it — to little for economic extraction. In a word, if you want more energy, spend it. If you want less waste, make more of it. If you want safe nuclear power, build new plants, to stimulate development of new, safer designs.
    One of the reasons for promoting of “efficiency” is stopping of development of new, inherently safe, clean and sustainable nukes, for the benefit of allied fossil and green lobbies.

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