Kevin Jacobson

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The U.S. Really Needs to Recycle it's Radioactive Waste. Here's Why.

The U.S. is going to go Thorium withing the next couple of decades. What I mean is that we are going to start using commercial LFTR instead of modern Uranium/Plutonium reactors. But, before we get there, the U.S. NEEDS to recycle it's radioactive waste. You hear scientists complain about how modern nuclear reactors are consuming more Uranium at an exponential rate which is a horrible thing since Uranium is only around a quarter as common as Thorium. Well you know what I say about it. DO SOMETHING ABOUT IT! Recycle radioactive waste! Going Thorium is definitely doing something about it, but LFTR's won't be a main power source for a decade or more. If radioactive waste was recycled, so much fuel would be saved. I believe that this would reduce the the stress on the remaining Uranium supplies and would reduce the amount of waste dumped in waste sites. If you took the tons of waste from all the dumping sites and reactor pools, just imagine how much fuel would come out of that. I know you would have to build reprocessing facilities, but it would be well worth it. What do you think?

  • Aug 6 2012: Uranium dioxide can be used for solar cells.
  • Aug 5 2012: I think Is it possible to bombard Thorium 232 with Helium 3 in plasma form to transmute the atom to U235 and at the same time fision the atom. A blanket of U238 can be transmuted and used on government regulated fast breed nuclear rector plants.

    The ionization and acceleration process on He3 looks more efficient and we can find He3 in the moon which makes the reaction proliferation resistant by controlling the He3 supply.

    I do not make the calculations. If you do please let me know.
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      Aug 6 2012: You could also have a Plutonium core surrounded by radium encased in Beryllium so the alpha emissions from the radium could produce neutrons to fission the Plutonium. And surrounding that would be more Plutonium and surrounding that could be Thorium with shavings of Plutonium in it to help boost reactions. I'm not sure if I explained this well enough but I hope I did.
      • Aug 6 2012: It will be great that nuclear fuel design become our future revolution.
        A good simulator software will be great for this process.
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          Aug 6 2012: I agree. Especially since fossil fuels simply won't be able to produce enough energy for our needs unless you increased consumption by a lot.
  • Aug 3 2012: "Reprocessing LWR waste" is very complex, and very controversial. There are simpler methods.

    Separating uranium from the nuclear waste is a simple chemical process (fluorination, already used in preparing light water reactor fuel). Then use the uranium in a LFTR or other molten salt reactor.

    That one step reduces the waste from light water reactors to almost completely fission products, Virtually all of which have half lives so short they are safe within 10 years (83%) or 350 years (17%). We know how to store each of these elements for 350 years.

    The few elements with longer half lives 1) aren't very radioactive (that goes with long half lives) 2) are produced in small quantity 3) can be separated and bombarded with neutrons (either in the LFTR or a special neutron source) so they are transmuted to elements that have short half lives.

    People in the LFTR community are developing the specifications and regulations, what elements in what amounts would be in LWR waste, and how would each element best be stored.

    Keep reading on http://liquidfluoridethoriumreactor.glerner.com/
  • Jul 31 2012: As you mention, antimatter is a new field that can yield new ideas.

    Nuclear spallation in where a proton is fired at nearly 1 GEV to basically destroy the nucleous and yield over 100 high energy neutrons.

    Japanese researches estimate that an accelerator with efficiency greater than 50% can be economically operated for comertial energy production.
  • Jul 28 2012: One of the major engineering road blocks on achieving this goal is neutron balance. U238 produce only 2.08 neutrons per reaction, one is consumed on the transmutation and 2 to 3 neutrons are used for fision on the termal spectrum. The transmuted product only produce 1.67 neutrons per fision reaction. To achieve this purpose it is necessary to assist the reaction with an external source of neutrons and advances in the fast neutron reaction field. A neutron with energy grater than 2MeV is necessary to break the U238 nucleous without transmutation and those 2MeV neutrons can be achieved on today's neutron generators. No transuranics will be produced on the process.
    If efficiency on neutron generators increase above 50% the scientific comunity is confident that DU can be used as fuel economically. There is a lot of interest on high efficiency neutron generation arround the world for this reason.
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      Jul 30 2012: You can also induce fission in fertile material with positron emission.
  • Jul 27 2012: I agree, there is big interest on LFTR through the world.

    I know I'm off topic but I was reading a paper regarding Aqueous Homogeneous Rectors (1949 to 1958 research) and it comes to my mind the following idea:

    A very fine thorium fluorine particles (nanometer range) covered with a moderator material and submerged in a liquid (not water). It will behave as slury.

    That may give extra flexibility to a reactor. The fluid can behave as a liquid or as a solid when you need it. It can be separated by density, by magnetic force or by ionic force, The slury can be cooled down, processed and heated again. Just a idea it occurrs to me.

    The two fluids reactor can be used without the risk of mixing due to the neutron erosion.
  • Jul 27 2012: I agree that nuclear waste needs to be recycled, specially the transuranic wastes.

    The waste of such gigantic amount of power really makes no sense to me either.

    We need an economical alternative to process those materials.

    As I understad the thechnology for that is not comertially available yet.

    Sadly, we will need to wait until the technology become available.

    Bill Gates belives in that and give 1B to design the Heat wave reactor for that purpose, but it is 40 years in the future.

    I think the best way is to design a self breed molten salt reactor as you propose.

    Maybe I'm wrong but for me small units that can breed fuel on demand conditions makes sense to me.
    Smaller units can be mass produced are more easy and cheaper to fabricate, transport and maintain than one big unit.

    Diesel cost $0.37 per KW of thermal energy and transportation energy such as merchant ships is a very attractive business.

    You need to effectivelly remove the fission waste from the main core if you want to make such as small fuel on demand unit.

    Leave only fuel on the main core. This ensure your fuel stock is maintained at a minimum and breeding is maximised.

    This also ensures that even if the reactor is stolen and opened, the fuel material is not enough for nothing.

    Investigate if the new technology of magnetic separators for liquid compounds can do the trick.

    Uranium is paramagnetic but high fluorine and the temperature can be a big challenge.

    The blanket that separates the two fluids can be an issue but if the unit are portable, a specialized factory can deal with all the issues and gives a level of insurance that only regulated facilities can give.

    A fuel spoiling system in case of tampering will also add a level of security.
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      Jul 27 2012: I have an idea on how to economically reprocess the waste. If you have a laser beam that gives off energy equivalent to the energy differences between the different elements in radioactive waste, you can separate two elements at a time from the waste. This is one of the proposed ideas on how to enrich uranium because the atoms of U235 and U238 have slightly different energy levels.

      And for when you spoke about molten salt reactors, they all ready exist but they haven't gone commercial yet. They are called Liquid Fluoride Thorium Reactor's (LFTR). The Thorium232 fluoride is dissolved in liquid salt and is transmuted into Uranium 233 which is fissile. The good thing about LFTR's is that they are almost 100% efficient and the radioactive waste produced would only be a threat for around 350 years.