What if I told you that most of those concerns can go away within the decade with a innovative new form of Nuclear Reactor?
Basics
There are three known methods of viable nuclear energy to be made from natural materials. First, is by mining Uranium ore, and isotopically separating the U235 out and burning that. U235 is expensive, it is about as rare as platinum, and much more difficult to separate. Moreover, in current solid fuel technology, only about 1-1/2% of the material is actually used. The remaining portion is then stored as waste.U238 can be hit with a neutron, converted into Pu239 and burned in a reactor. This is much better as there is far more U238 than U235, but there is still the issue of nuclear proliferation as the plutonium is reprocessed and the long term storage of spent fuel rods.
Thorium 232 is a naturally occurring material (Atomic No. 90) about 3 times as common as U238. It's half life is 14.5 billion years (essentially not radioactive in it's natural state). It can be hit with a neutron, which will convert it into Protactinium 233, then U233 through a couple beta decays. U233 is a fissile material, but it also has a short half-life. This short half life makes it unusable in nuclear bombs. That is the reason nobody has used it in nuclear power plants. Nuclear weapons technology from WW2 was used to develop U235 and Pu 239, while the Thorium breeder cycle was just set aside. The time has come to develop this energy source.
All nuclear reactors today are based on solid fuels. Solid pellets are arranged closely together so emitted neutrons split atoms and sustain the reaction. It is possible to use liquid based fuels. This was in fact demonstrated in Oak Ridge National Laboratory in the 1960's. Uranium 235 was dissolved in floride salts and used to run a reactor for several years. That ended in 1973 when funding for developing this reactor was cut. This was a big mistake in my opinion.
Why a Liquid Floride Thorium Reactor (LFTR)
Using Thorium has several advantages. Because of it's chemistry, it can be processed in a closed cycle within the reactor to be burned up at 99% efficiency (compared to the 1-1/2% efficiency of today's solid fuel reactors) In other words, it would take 60 LFTRs to put out the same waste as a single U235 reactor.The (simplified) process is as shown:
Basically, through chemical processing, the Uranium created by excess neutrons in a vessel surrounding the reactor is separated chemically and fed into the reactor to be burned. The actual process would involve more steps to remove the final waste products (of which most could be used elsewhere).
A 1950's technology reactor we use today uses water as a heat transfer medium. This is bad because water is normally a vapor at these temperatures. The water must be pressurized to be contained and keep the reactor cool. . This high pressure steam was a problem in Chernobyl, Three Mile Island, and Fukushima. A liquid salt reactor will not be under pressure, eliminating that problem. Moreover, the new design has a freeze plug, which must be actively cooled to keep from melting. If there is a problem, the salt in the plug will melt, allowing the material in the reactor to drain into a tank shaped to make criticality impossible, the fuel would simply drain out of the reactor into a tank, and freeze solid until repairs are made, at which time the material can be reheated electrically and pumped back into the reactor chamber. This makes accidents far less likely.
Water is a covalently bonded molecule, meaning the ionizing radiation in a reactor will split the hydrogen and oxygen into its separate elements until it is reburned in a collection vessel. Ionicly bonded salts do not have this problem. The detached ions will simply be jostled around by the ionizing radiation, but they remain in the compound. Hydrogen explosions occurred at both Chernobyl and Fukushima, increasing the hazard.
One of the bigger issues with current reactors is the production of Xenon 135 (a noble gas). It decays quickly, but it has a propensity to absorb neutrons. People who work on reactors are always fighting with the stuff, balancing out the control rods and fuel concentrations. This makes the reactors far more unstable. In a liquid based reactor, that gas bubbles out of solution, eliminating that problem. It was a major component in the Chernobyl accident.
Thorium also has an advantage of being lighter on the periodic table. Because of this, there would be far less heavy actinide waste made in the reactor. These are the heavier materials with the long half-lives which will be persistently radioactive from today's reactors. By comparison, a typical U235 reactor will generate waste which will remain more radioactive than the Uranium ore for about 300,000 years while the Thorium byproducts (1/60th the amount) will be excessively radioactive for about 300 years.
Some Disadvantages
Really there aren't many. There are some startup technology problems with refining the chemical processes, corrosion issues with dealing with hot salts, and regulatory issues with government in licensing a revolutionary system. Several start-up companies are working on them as we speak. China is pushing ahead on the technology and is expected to have a full scale reactor within 5 years, India is also pushing ahead. The main holdup is the US government right now. That will probably change when China comes online.The Future
From what I seen as a kid as their promise of fusion technology, this looks like it solves most of those problems. A single cubic yard of average common dirt has as much energy from Thorium as roughly 150 barrels of oil. The world's use of energy would be essentially limited only by our imagination. With plentiful, cheap energy, the whole world could be lifted out of poverty, common waste can be recycled. A landfill could be mined for it's resources in there. Fresh water could be created in many dry areas. Fuels could be manufactured. Whole societies have changed with far smaller changes in our energy production than this.https://www.instructables.com/id/LFTR-the-New-age-of-Nuclear/
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