MSR Benefits

Molten Salt Reactor Advantages

  • Molten Fuel - Fuel circulates through the reactor, fission products get removed, for over 99% fuel use (vs. LWR ~3%). No long-term radioactive waste.
  • Salt Cooled - Coolant far below boiling point, reactor operates at atmospheric pressure. Fuel dissolved in stable salt (no water), no loss of coolant accident possible. No need for high-pressure safety systems.
  • High Inherent Safety - No water, no high pressure, nothing that could propel radioactive materials into the environment. Thermal expansion/contraction of molten fuel salt strongly regulates fission rate; MSR is a very stable reactor. Simple safety systems work even if no electricity or operators.
  • Easy Construction and Siting - Low pressure operation, so no high-pressure safety systems. No water, so no steam containment building. Reactor factory assembled, with modern quality control, sensors and communication.
  • Lower Cost - Even with exotic materials, construction costs will be dramatically lower than LWR — factory construction, minimal manual on-site preparation. No long-term radioactive waste, so no long-term storage.
  • High Temperature Operation - Heat to generate electricity, desalinate water, produce CO2-neutral vehicle fuel, etc.
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My responses to article and comments for http://www.nytimes.com/2013/08/21/business/economy/coming-full-circle-in-energy.html

R Lee, New Mexico said “The main issue with nuclear power is the waste. All nuclear power alternatives have waste streams that must be addressed. The US has fallen far behind in disposal, and megatons of waste are simply piling up. Even if we stopped using nuclear energy tomorrow we would still have to deal with this. A reasonable solution is to address the waste issue first, then explore nuclear energy options.”

We DO know how to deal with nuclear waste, just stop using Light Water Reactors. LWR is not the only kind of nuclear power!

Nuclear Regulatory Commission is protecting Light Water Reactors (LWR), but other than political reasons, we could switch to types of nuclear reactors with salt coolant instead of water (no risk of Fukushima-type problems) and with molten fuel instead of solid fuel (fuel rods and pellets prevent all fuel being fissioned). 98% of the uranium in LWR is “waste”, not because the uranium is somehow defective…

We’ve known what to do with nuclear waste from LWR since 1960s, when Oak Ridge National Laboratories (run by the patent holder on LWR) ran the Molten Salt Reactor Experiment. Operated it over 5 years, worked fine, killed politically by LWR people. A modern version could take waste from LWR, no “reprocessing” needed, and use it.

Without uranium in the waste, most MSR waste is safe in 10 years (just like LWR fuel rods stay in cooling ponds 10 years), a little 350-year waste (about 300 lbs per GW-year electricity), and Nothing Longer.

http://liquidfluoridethoriumreactor.glerner.com/ shows clearly how MSR takes care of the safety concerns of Light Water Reactors, with no high pressure or water; and eliminates (not buries) nuclear waste.

While making CO2-free electricity, MSR also can provide heat for CO2-neutral gasoline, desalinated water, and other high-temperature industrial needs, further reducing use of high-polluting coal/oil.

Dr. John Miller, Twitter @NuclearReporter said “Reply to George Lerner: There is no nuclear reactor that does not leave a waste stream. If the reactor contains U-238, it leaves some plutonium 239 that must be stored for 240,000 years. Read my article in the New York Times last Friday: http://dotearth.blogs.nytimes.com/2013/08/16/a-nuclear-submariner-challenges-a-pro-nuclear-film/

(Comments are closed on the “Coming Full Circle…” page, I can’t respond there.)

Only if we remove Pu-239 from the reactor. I was not talking about a solid-fueled reactor; much of what you know from LWR doesn’t apply.

Few facts about solid fueled, water cooled reactors apply to molten fueled, salt cooled reactors.

Pandora’s Promise discusses benefits of MSR, incl passive & inherent safety, and you keep “refuting” it with LWR facts — wrong technology!

In a molten salt reactor, we never would have to remove plutonium. We would want to keep it in the reactor, it is Fuel. Whether the Pu came from the LWR or from U238 absorbing a neutron in the MSR, it would stay in the MSR until it fissioned.

Well-known chemical processes can separate all the trans-uranic elements from the fission products — big advantage of molten fuel, so we can Fission 99%+ of U or Pu fuel.

Without uranium and transuranics in the waste, the rest of the radioactive waste (the fission products) is much simpler to deal with. Most (83%) of MSR waste would be below background radiation levels in fewer than 10 years. About 300 lbs per GW-year electricity to store 350 years. NOTHING longer.

We operated Molten Salt Reactor Experiment, successfully, in 1960s.

We have a solution to long-term nuclear waste. Fission it, don’t bury it. Light Water Reactors can’t use it, but other types of reactors Can.

http://www.thoriumenergyalliance.com/downloads/Molten_Salt_LeBlanc.pdf says “Perhaps a new term of “effective” conversion ratio would be to compare fissile consumption versus needed annual fissile additions. By this metric, most other reactors on a Once Through cycle have effective conversion ratio of near zero since they consume about 1000kg/GW(e) year but need to add 1000kg of fissile 235U per year. Even with Pu recycle, they do not improve dramatically. Thus the great advantage of molten salt converter reactors is that all plutonium produced stays within the core for the full lifetime where it is mostly consumed.

“In terms of long term radiotoxicity of wastes, these converter designs also perform remarkably well. All transuranics remain in the salt during operation… At the end of 30 years there is only about 1000kg present. [The specific design he is referring to at this point in his paper has no processing at all for 30 years, then the fuel is removed.] It is presumed prudent to perform a one time only process to remove these transuranics for recycle into the next core salt. If this is done and a typical processing loss of 0.1% is assumed, this represents a mere 1kg of TRUs going to waste over 30 years which is about a 10,000 fold improvement over LWR once through… It should be mentioned that removing and reusing TRUs does not involve isolating plutonium. The likely process would be Liquid Bismuth Reductive Extraction and Pu would remain with Am, Cm, Cf and the fission product zirconium.”

(If 10,000 fold improvement isn’t good enough, we engineer to tighter standards or add another transuranic removal step. I have no information about how much of that 30g/GW-yr is plutonium, but it certainly isn’t “weapons grade”.)

Removing uranium is a simple fluorination process, converts uranium to UF6 gas; equipment for this is currently used as part of uranium enrichment, those centrifuges work on gasses; I wouldn’t be surprised if better than 0.1% processing loss is standard.

We have simple solutions to deal with waste from Light Water Reactors. We would, however, have to stop thinking of Light Water Reactors as the only type of nuclear reactor that is possible. The designers of the LWR didn’t, the Atomic Energy Commission didn’t (see Civilian Nuclear Power–1962 Report to President Kennedy and Congress ).

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