Are Small Modular Reactors the Answer for Energy Sustainability?
The recent energetic and climatic woes around the world have our top experts scrambling for more ‘clean’ energy sources -one more chapter in their continuous race towards an ideal source with no emissions and high sustainability. This race is so full of pitfalls that any outside objective viewer –possibly an enlightened extraterrestrial- would most likely consider the whole thing as a comedy of errors! In this comedy, we are serially enthralled by the newest energy solution that will fix all our problems, only to very soon find its limits and lack of true cleanliness.
The fossil fuel crunch that many countries are experiencing has shown governments in rich and poor countries that their renewable energy efforts are not enough to fuel their industrial and agricultural needs, leading them to unseemly behaviors like reverting to the even more polluting coal. The present act in this comedy of errors deals with the latest energy solution -the move to Small Modular Reactors (SMR), sometimes combined with natural gas.
This solution is being proposed by the European Union, several world institutions, the Biden administration, and the Bill Gates foundation, as a clean and sustainable energy source that will preserve our present way of life. The ‘greening’ of natural gas as clean energy bypasses the fact that natural gas is the euphemistic name for methane, the gas that cows emit. In this incredible comedy or errors, the above experts insist that we should stop eating methane-producing cows to save the planet, while they completely bypass the much higher methane emissions produced as a byproduct of fracking and natural gas production, and the even greater quantities naturally emitted from the melting of the permafrost. Their other ‘clean’ solution takes out of the sleeve the old nuclear energy card, reformatted and varnished to appear clean -only if we ignore the tiny problem of radiation!
Nuclear energy is not even free of the dreaded greenhouse emissions –just like any other energy on Earth -its raw materials are mined, manufactured, and transported while producing their corresponding amounts of waste. The added risk of radiation creates innumerable problems that plague this energy from mine to grave in processes that could not be performed without the dense energy from fossil fuels. These facts already put quite a few holes in the perfect green narrative of nuclear energy as an ideal energy option.
Let’s now look at the next act in this comedy of errors in which the actors pretend that reducing the size of the nuclear reactors magically reduces the risk of radiation -a “insignificant” problem that can affect the environment for tens of thousands of years. In effect, the proposals for these smaller and modular reactors (SMR) envision their installment near towns and cities, making them easier to install and increasing their effectiveness by avoiding electricity transmission from distant places.
Their advocates insist that they reduce the carbon footprint and produce less toxicity and radiation though they don’t seem to have seriously verified much relevant information to sustain such claims. A good example of this is the 2020 (IAEA) International Atomic Energy Agency’s publication Advances in Small Modular Reactor Technology Developments. Their description of these new reactors concentrates on their ease of assembly and innovative qualities, but little is explained about the realities of operation and nuclear waste management.
To put these SMR proposals in perspective, it is good to see how nuclear energy and the supposedly renewable energies are faring at present: according to Our World in Data, in 2021, nuclear energy provided 4% of the total global energy while modern renewables just about 5.82%. Hydro-power produces about 7.4%, which added to the above numbers gives us a total of 17.22% of the current energy that is not provided by fossil fuels. This implies that a complete replacement of these dirty fuels would require an exponential increase in nuclear and modern renewables, correspondingly sharply augmenting the mining of uranium and other toxic commodities.
The majority of these supposed cleaner reactors –just like the older ones- still use uranium as their main fuel. The uranium pellets are sometimes mixed with thorium, fluoride, or iodine and the coolants and moderators can include light water, (water with less deuterium, heavy water (water with more deuterium), graphene, and salt.
Uranium mining, whether for big or small nuclear reactors, is still equally toxic and environmentally damaging –most is still done in open pits or more recently, ‘in situ’ leaching. In the first method, the ore is crushed in a mill and mixed with water to produce a mush of fine ore particles and other materials. This mush is then leached with sulfuric acid or an alkaline solution to dissolve the uranium, leaving the remaining rock undissolved. The supposed cleaner method -in situ leaching- is done by injecting water with oxygen into the rock to extract its uranium ore. In both cases, the ore is then transported and turned into a powder that is later formed into pellets and assembled in rods –a complicated operation that produces waste at all stages.
Let’s now continue with some of the usually ignored ‘unclean’ pitfalls in this act of our comedy of errors! The current yearly raw uranium consumption per big reactor is 250 tons of uranium, which produces about half a million tons of waste rock, 100,000 tons of mill tailings, 144 tons of solid waste, and 1343 cubic meters of liquid waste. This waste has different levels of toxicity and radiation that has the potential to spread mining byproducts to aquifers and whole ecosystems. This damage will logically increase as we extend our nuclear energy use in our race to replace fossil fuels
The pitfalls continue with the nuclear plant’s operation. The fission of nuclear fuel produces lots of harmful radioactive isotopes like tritium, carbon 14, iodine-14, and krypton-85 -all of which can be spread by aerosols during the fission process or escape into the coolant and moderator through defective fuel cladding. The whole operation has the potential of spreading to the atmosphere, water bodies, and nearby sediments. The variations of radiation dangers are endless: Krypton is quite difficult to control, which makes it highly mobile in the local environment; iodine 129 can have radioactive effects worldwide, and Carbon-14’s long life allows it to accumulate in the environment.
These problems are exacerbated by the smaller space in these new reactors, invalidating the claims of diminished risks of radiation. In effect, according to a Stanford University study published in the Proceedings of the National Academy of Science in June 2022, the diminished risk of radiation claim is very far from the truth. The small modular reactor’s designs produce not less but potentially more than five times the spent fuel per unit of power and about 35 times more nuclear operation-related waste. To make matters worse, the smaller space in SMRs creates a problem with the neutrons fired into uranium atoms, a necessary step for making nuclear energy. The confined space forces the bouncing neutrons to hit not just the uranium atoms, but also the outer parts of the reactor’s core, turning these materials radioactive.
Some SMR proposals encase the core in steel and graphite that reduce the neutron activity, but these are still heavily bombarded, inevitably becoming damaged and radioactive at some point. This means that these parts would have to be replaced often, creating not just problems for the continuous operation of the reactor, but also increasing the radioactive waste. The coolant or moderators also have a high chance of becoming radioactive, leading to an even higher amount of radioactive byproducts, very difficult to deal with, especially in a culture obsessed with profit and ‘productivity’. This comedy of errors is quite evident in the trials of SMRs in Scotland and Tennessee -they have ended in a quagmire, unable to dispose of all radioactive components that these ‘cleaner’ reactors produce.
Another proposal to reduce the excess of radioactive components in SMRs is to use more enriched uranium, thus decreasing the neutron leakage. In effect, Uranium 235 has more available atoms for neutrons to reach, lowering the chances of wayward neutrons. Unfortunately, this also increases the volume of spent fuel and the concentration of fissionable atoms in the waste, making it even more volatile and problematic. This means that the waste has to be divided into smaller batches for safe-keeping, creating tons of logistical problems.
Our comedy of errors is at this point turning into a tragicomedy where the characters also seem to ignore the reality of our present handling of dangerous nuclear waste. Such toxic material is usually treated as a nuisance that we conveniently place in low-populated areas, poor countries, or the sea while avoiding many safety measures. The transition to small reactors will certainly not change this attitude, even if these reactors have more radiation problems.
The present standard nuclear waste management follows these steps: first, the waste is stored in situ, and then brought to a safe final depository that will supposedly keep it completely isolated, not producing any harm. The proposal for SMRs near many towns will increase the locations of in situ storage of spent fuel which comes very hot out of the reactor and has to be stored in cooling pools for a while. It is difficult to imagine a great number of towns surrounded by a series of buildings with pools holding very radioactive material for a long time.
The spent fuel remains in the pools waiting to be recycled or put in dry casks to go into its supposed final and safe depository. This act of the comedy of errors continues the pitfalls when we learn that we have not yet found a safe and stable depository to put the current US accumulation of at least 82,000 metric tons of spent nuclear fuel. There are about 80 sites in 35 states where the waste remains in pools, steel, or concrete casks, posing a threat to many people.
Our best idea for a safe depository has been the use of natural geological formations like Yucca Mountain in Nevada. This site was first proposed in the 1950s, supposed to open in 1987 against the will of all Nevadans, and then used as a political battleground until the project was finally abandoned in 2010, unfinished.
A more recent idea was proposed by a father and daughter team, Richard and Elizabeth Mueller, who have created a startup company called Deep Isolation. Their new technique involves drilling boreholes deep into the ground to expand the places where the dry casks could be eternally stored, avoiding the need for natural geological formations. Their latest efforts adapt to the small reactor’s ideas by providing the possibility of burying the waste in situ forever in underground holes, avoiding the cumbersome shipping of the waste to centralized depositories.
Their assurance of the feasibility and safety of their proposals is clouded by US Department of Energy studies which found in the 1980s the problems inherent in burying nuclear waste in bored holes 3 to 5 km depths. Deep Isolation claims to bypass these studies by limiting the depth to about 2 km, though recent studies in Sweden and the UK show that these are as unsafe and unfeasible, as the ones used in the Department of Energy study. The drilling of deep holes of a diameter that would fit big enough waste canisters is not very easy and this diameter limitation implies that the canister walls would have to be very thin to allow efficient storage. In turn, the need for thinner canister walls increases the probability of damage and radioactive material exposure.
In this comedy of errors, the towns with supposed small modular reactors would look like a radioactive nightmare! Just imagine towns surrounded by small reactors leaking neutrons that turn many materials radioactive, with pools of spent fuel that is later permanently stored in very thin-walled canisters fitted into narrow tunnels drilled nearby. It is certain that the tragicomedy has taken a darker turn!
Our comedy of errors is getting to its temporary final act but it will continue with the next idea for clean and sustainable energy that could replace fossil fuels. These proposals will always claim some degree of cleanliness, mostly only at the source, while the rest of the unsightly and dangerous waste is conveniently ignored.
Our culture has finally accepted that greenhouse emissions and pollution are bad for the systems of the Earth, but why do we still fool ourselves by presenting nuclear energy as safe, when it is also full of very harmful effects? Very simple, our human nature has three characteristics that are essential for this behavior: we love to solve problems, we are sure there is a solution for each problem, and we practice self-deception when reality doesn’t suit our wishes. To top it all, our current cultural values prioritize eternal hope, profit, and productivity without caring much about reality. In conclusion, we are destined to follow ghostly ‘green’ solutions that like fireflies, lose their brilliance very quickly, only to appear somewhere else. Mesmerized by these visions, we will continue business as usual until it is no longer possible.
