Nuclear Energy: Should Generation IV Reactors Be Developed?
Many types of alternative energy are being developed in an effort to move away from burning fossil fuels, but perhaps the answer to the problem has already been in use for many years. Nuclear energy currently provides about 14% of the world’s total energy, and the plants that produce it are getting constantly more efficient (“Nuclear Power”). Unfortunately, the efficiency of existing plants is limited due to their design. Light water reactors, or LWRs, were developed in the 1950’s and are still used across the globe as primary method of obtaining nuclear power, albeit newer models use simpler and safer technology (“THE NEXT GENERATION”). The problem with LWRs is that only 1% of their uranium fuel can be used to create energy, and they produce large amounts of radioactive waste in the fission process (Hansen). Even though waste is securely stored, it is still believed to be an environmental threat because of how long it remains radioactive ("Radioactive Wastes”). The possibility of environmental harm has put many off to the idea of the next generation of nuclear energy, but Generation IV power plants should replace existing ones worldwide; they will be safer, at least one hundred times more efficient, and capable of using existing nuclear waste as fuel.
When nuclear power was first being developed, reactors needed to compete with large oil and coal burning plants that dominated the market. Energy needed to be produced as efficiently as possible to reduce operation costs and provide cheaper electricity than the fossil fuel plants were offering. It was found to be cheaper to build and operate plants with higher energy output so single 1,200,000 kW plants were used in favor of pairs of 600,000 kW plants, even though it required the plants to dissipate twice as much heat which put them at a safety disadvantage (“THE NEXT GENERATION”). Two of the proposed Generation IV nuclear reactors, Integral Fast Reactors (IFRs) and Liquid-Fluoride Thorium Reactors (LFTRs), would far surpass the safety levels of any reactor thus far (Hansen). To start, since safety is more of a concern than efficiency in today’s market, 600,000 kW reactors will replace the current “bigger is better” method of building. Also, IFR and LFTR plants will be able to work at lower pressures than existing plants which drastically reduces the chances of Loss-of-coolant accidents (Hansen). If loss-of-coolant accidents (LOTAs) are not handled quickly, they can lead to core damage and eventually nuclear meltdowns, and in the off-chance that a LOTA occurs in a next generation reactor, there will be already-tested safety systems that will allow the plant to safely shut down even in the event of serious accidents (Hansen)("Decay Heat” 61). Improved safety is a major selling point for Generation IV nuclear power plants, but since there have been very few nuclear accidents, the power per unit of fuel is arguably a more drastic improvement.
Integral Fast Reactors and Liquid-Fluoride Thorium Reactors are both said to be one hundred times and three-hundred times more efficient that Light Water Reactors respectively. Only about 0.7% of uranium consists of the isotope U-235, the fuel source of nuclear reactors, but because the cooling process utilized by LWRs absorbs a significant number neutrons required for fission, nuclear fuel must be enriched to contain between 3% and 5% U-235. The enrichment process requires large amounts energy and could be avoided by using more efficient reactors which do not need enriched fuel (Barton). Not only would LFTRs and IFRs require non enriched fuel in order to operate, but they would also utilize the fuel to the fullest extent. LWRs are only capable of burning about .6% of U-235 in the fuel and the rest is “depleted” or “spent” fuel which is discarded as radioactive waste. Since LFTRs and IFRs are able to operate at much higher temperatures than LWRs, they can more thoroughly burn uranium and burn it more efficiently turning up to 85% of the heat into electricity as opposed the 30% of heat that LWRs turn into electricity (Hansen). LFTRs which will utilize thorium as a primary energy source will be able to produce over 30,000% more energy per megaton of fuel as the current method of burning uranium only amounts to about 35 GW*hr/MT while a LFTR would produce about 11,000 GW*hr/MT (Barton). Efficiency is a great advantage over the current generation of nuclear power plants, but the one of the greatest redeeming qualities of Generation IV reactors is that they will be more environmental friendly than present-day models.
Nuclear waste turns many people off to the idea of nuclear power becoming the next dominant source of energy, but the fact is that Generation IV plants would solve most problems associated with nuclear waste. Some complaints are that, “Some of these radioactive isotopes are extraordinarily long-lived, remaining toxic for hundreds of thousands of years” (Lai and Morrison), and “The nuclear industry still has no solution to the 'waste problem', so cannot expect support for construction of new plants until this is remedied” (“Radioactive Waste”). IFRs offer solutions to both of these problems. To start, IFRs can use existing radioactive waste as fuel which prevents the need to mine for new fuel sources, and according the estimates made by the World Nuclear Association there is enough usable nuclear waste to power IFRs for the next several centuries (“Nuclear Power”). In addition to using up the radioactive waste made by LWRs, the IFRs will produce waste that will remain radioactive for only a few centuries as opposed to hundreds of thousands of year (Hansen). In the case of LFTRs, which can also utilize spent fuel, the amount of fuel required to operate them is so miniscule that they will produce 300 times less waste. To put the amount of environmental harm in perspective, a coal-burning plant produces more radioactive material per megaton of fuel than a nuclear power plant, and more radioactive particles have been released into the environment by burning coal than every nuclear disaster since fission energy has been in use (Hvistendahl 1). Even though Generation IV nuclear power plants will pose some risk to the environment, it will be far lower than coal or current nuclear power plants.
The benefits in developing Generation IV nuclear power plants far outweigh the possible risks. Plans to build smaller reactors that operate at lower pressures will ensure that the chance of major catastrophes will be reduced by more than ten-fold when compared to the low rate at which they already occur (Hansen). Efficiency will also be increased to by more than 100 times. There is enough uranium and thorium already mined to supply all of the world’s power for more than a millennium; and this includes fuel that was previously considered waste (Barton). As for environmental impact, the negative effects nuclear energy has already had is a major setback to developing newer technology, but Generation IV reactors are the best solution to the problems that previous generations of nuclear reactors have created. The IFRs and LFTRs would be much less harmful than fossil-fuel burning plants, which now provide over 80% of the world’s energy (“Nuclear Power”). Although developing the next generation of nuclear power plants would possess some risks, they are much safer, cleaner, and efficient than any coal-burning plant or current nuclear power plant.
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