In this chapter, we’ll go over the first technology that provides the electricity-generating base of the Universal Energy framework. It’s an advanced type of nuclear reactor known as a Liquid Fluoride Thorium Reactor, and what makes it special is the fact that it’s both ultra-clean, ultra-powerful and allows us to avoid nearly every complication we face with nuclear power today (we’ll call it a LFTR for short). After reviewing its capabilities, we’ll then shift gears to the other technologies that work alongside this reactor to generate enough energy to produce critical resources at acceptable costs.
Liquid Fluoride Thorium Reactors
To put it mildly, nuclear power does not have a ton of public support today. And it’s understandable. Considering the meltdown and radiation leaks at Fukushima, the unrivaled toxicity and longevity of nuclear waste, and the fact that nuclear power plants can also be used to make nuclear bombs, much of the ire is justified. But a point of importance is that these problems have very little to do with nuclear power as a concept. These problems, rather, stem from how nuclear power plants are constructed and, more importantly, how they are fueled. A LFTR is fueled by the element thorium – as opposed to uranium – to provide clean and safe nuclear power that avoids most obstacles to nuclear power today. Here’s a short list of its benefits:
- LFTRs are highly efficient, hundreds of times more so than Pressurized Water Reactors (the uranium-fueled reactors that we use today).
- LFTRs are extremely safe. Because their fuel and reactant is liquid and they are not pressurized, it is physically impossible for the catastrophic results of a traditional “meltdown” to occur.
- LFTRs produce far less waste than Pressurized Water Reactors and can also consume nuclear waste and weapons-grade nuclear material as fuel. Of what small amounts of waste remain, it takes only decades for it to become non-radioactive, as opposed to thousands of years with uranium-fueled reactors.
- The primary fuel supply of LFTRs, thorium, is highly abundant – about as common as lead, making it thousands of times more plentiful than fuel-grade uranium (only about 0.7% of all uranium on Earth).
- The thorium fuel cycle in LFTRs is prohibitively difficult to weaponize, and even if one was able to make a nuclear weapon from the reactor it would likely not be feasible to deploy in a military capacity.
- As a result of their efficiency and safety, LFTRs can be much smaller than Pressurized Water Reactors, on the order of a house as opposed to a multi-acre compound that requires a large buffer zone in case of emergencies.
- These factors make LFTRs less expensive to build than Pressurized Water Reactors, and due to their small size, allows them to be mass-produced on assembly lines in a modular and standardized capacity, meaning that nuclear reactors can become iterations of a product model as opposed to single entities.
LFTRs are superior to today’s Pressurized Water Reactors in most every way they could be and their proven designs have been known to science for decades. But that prompts a natural question: why aren’t we using them today? To answer that, we’ll need to provide some background that is easier to understand by first reviewing a few terms surrounding atomic energy. Don’t worry, this isn’t a textbook! It’s just a quick overview if you’re not familiar with nuclear power (or you’re like me and slacked off in high-school science classes).
Atom: the building block of matter. Generally speaking, each atom has a central nucleus that contains two types of particles – protons and neutrons, which are orbited by a given number of electrons. The different elements in the world are made up of atoms, and each element has a specific atomic composition, as shown by the periodic table of elements. [nifty video]
Radioactive decay: the process in which an unstable atom spontaneously emits radiation in the form of atomic particles or energy. An element or substance that naturally undergoes radioactive decay is considered to be radioactive.
Isotope: an unstable atomic variant of an element, usually as a result of radioactive decay and/or transmutation (explained next). Isotopes have number designations reflective of their atomic composition. For example: uranium-233 and uranium-235 are isotopes of the element uranium.
Transmutation: the process in which one isotope of an element becomes an isotope of another element through a nuclear process. For example: thorium-232 becomes uranium-233 inside of a LFTR after absorbing a neutron.
Fission: the splitting of an atom’s nucleus, releasing tremendous energy and fission products (usually radiation + isotopes of other elements). For example: uranium-fueled power plants today work by using a neutron to split the atomic nucleus of uranium-235 into kryptonium-92 and barium-141.
Fusion: the joining of atomic nuclei together to form a new element, releasing more energy than even fission. For example: fusing tritium and deuterium (isotopes of hydrogen) into helium, which is how our sun works.
Fissile fuel: an isotope of an element that can undergo fission directly inside a reactor. Uranium-233 and uranium-235 are fissile fuels.
Fertile fuel: an isotope of an element that can’t undergo fission directly, but can if transmuted into a fissile fuel. Thorium is a fertile fuel.
Breeding: a process in certain reactor designs that uses transmutation to transform a fertile fuel into a fissile fuel. Any reactor that undergoes the breeding process is considered a “breeder reactor.” LFTRs are breeder reactors.
Pressurized Water Reactor (PWR): 1950’s-era reactor designs that use highly pressurized water to help regulate and make possible a fission reaction inside a reactor core. Pressurized Water Reactors use solid fuel, and are the most common nuclear reactors operating today.
Molten Salt Reactor (MSR): advanced reactor designs that use a special type of non-radioactive salt that becomes liquid at high temperatures to act as both a moderator for the reactor and a carrier mechanism for nuclear fuel. They operate at standard atmospheric pressure and have a liquid fuel supply. MSRs can be fueled by most any nuclear material, similarly as breeder reactors. A LFTR is a highly efficient form of a Molten Salt Reactor.
With these terms defined, we’ll from here go over a bit of our history with atomic energy – specifically why we aren’t using LFTRs to generate power today.
Electricity AND bombs? How could anyone say no?
Most nuclear reactors today, including those within the United States, are fueled by uranium-235, an isotope representing less than 0.7% of all naturally existing uranium on Earth. Uranium-235 is a fissile fuel, meaning that the possibility exists for its atomic nucleus to split into isotopes of other elements if hit by a fast-moving neutron, releasing levels of energy that are millions of times greater than any chemical fuel source. For comparison, the energy released by burning a molecule of methane is 9.6 eV (electron volts), whereas the fissioning of a single uranium-235 atom releases 200 MeV (million electron volts) of energy. That’s a big difference.
For nuclear fission to work for energy production, it involves a concept known as “criticality,” a threshold in which there is enough fissionable material present for the reaction to sustain itself (a “critical mass”). As it exists in nature uranium is not capable of sustained fission, yet the isotopes uranium-233 and uranium-235 are if enriched to sufficient percentages within a fuel supply. If the reaction is sustained in a controlled environment like a reactor, it produces energy over long periods of time. This heats water, which creates steam that turns a turbine and generates electricity. But during World War II, government scientists discovered that certain fissile materials had a unique property: if enriched high enough, it could reach a super-critical state. And if it were to be rapidly bombarded with neutrons, it could create a nuclear detonation – the most powerful man-made force in existence.
As it was two of those detonations that ended World War II, the significance of atomic weaponry could not be discounted, especially once the Cold War unfolded in earnest. Thus, as civilian nuclear power developed as an energy source, so did the development of nuclear arms and their delivery mechanisms. These two sectors would eventually converge to ensure our continued use of uranium-235 as fuel.
For several reasons, uranium-235 is a less-than ideal fuel for nuclear power. For one, it’s very reactive, akin to filling a car’s gas tank with jet fuel. It’s also primarily employed within Light Water Reactors (and to a lesser degree, Heavy Water Reactors). Both Light and Heavy Water Reactors are Pressurized Water Reactors, which pressurize water to a level equivalent to a mile below the ocean’s surface so that it stays liquid at 626°F (330°C) in order to help regulate the nuclear reaction. So, why are these systems not optimal for society’s energy needs? The issues essentially boil down to risk management and efficiency.
Pressurized Water Reactors were invented in the 1950s and their designs have remained largely unchanged since then. As Light Water Reactors are by far the most common variants, we’ll focus primarily on them. They are fueled through rods filled with uranium-oxide pellets (that can contain no more than 4.5% fissile material). Those fuel rods must be replaced every 18 months – along with the reactor core. This requires shutting down the reactor; both the fuel rods and reactor core remain radioactively contaminated. If a reaction was to run awry and the fuel rods couldn’t be extracted, they could potentially melt and pool in the water-filled reactor core, generating extreme heat to the extent that a steam explosion could occur and spread radioactive contaminants over an area. That event is called a “meltdown” and is effectively what happened in Chernobyl. This is very bad.
These risks require Light Water Reactors to be built with extensive safety features: containment domes of steel-reinforced concrete several feet thick, massive cooling and pressurization apparatuses and redundant mechanisms that engage in case any of these systems were to fail. Light Water Reactors also must be built in sparsely populated areas with large buffer zones in case an area had to be rapidly evacuated in the event of a meltdown. All of these factors make Light Water Reactors extremely expensive to build and furthermore carry catastrophic consequences if anything was to go wrong. So, why are we using uranium-235 as nuclear fuel within Light and Heavy Water Reactors, especially since better alternatives exist?
Simply stated: because it was discovered that as part of the uranium-235 fuel cycle, it’s possible to reprocess spent fuel rods to artificially produce plutonium-239, and you need plutonium-239 to build hydrogen bombs.
Nuclear bombs come in varied shapes and sizes. Building a basic weapon is fairly straightforward if one has the materials. The general idea is to find a way to rapidly combine highly enriched fissile material together into a critical mass (explosives usually do the trick), introduce a neutron source to spark a fast fissile chain-reaction, and bam! You’ve got yourself a nuclear bomb.
The top part of the image below reflects a gun-type assembly device, the bomb the United States dropped on Hiroshima in 1945 (first of the two). As you can see, it’s conceptually simple. However, building a very powerful bomb that is still small enough to fit into a warhead requires an implosion-type assembly design, a means of reaching a critical mass by imploding a larger sphere into a smaller sphere by means of explosives (read: very difficult). Implosion-type devices can not only be much smaller than gun-type devices, they are also far more efficient and thus far more powerful.
But the thing with uranium-235 is that it isn’t very effective in implosion-type devices due to a high critical mass requirement – a trait not shared by plutonium-239. Yet plutonium-239 does not exist naturally in nature, leading our government to rely on the reprocessing of spent uranium-235 fuel rods in power plants to source it. Once acquired, we then took weaponization a massive leap further.
As implosion devices can be built to small size (basketball or smaller), we discovered that the energy released from its detonation inside a bomb’s casing can be harnessed to facilitate the fusion of isotopes of hydrogen, providing a dramatically more powerful explosion. Thus, the hydrogen bomb was born.
The following image shows the basic stages of a thermonuclear detonation, employing what is known as a Teller-Ulam device design:
By using the heat, radiation and pressure of an implosion-type bomb, thermonuclear weapons fuse isotopes of hydrogen together to create helium, forming a second sun anywhere one is detonated. With potential yields in the megatons, bombs can be built that make the ones dropped on Japan seem like firecrackers:
Yet as plutonium-239 is required to produce a thermonuclear detonation, without it, none of the thousands of hydrogen bombs in the world could exist. And without using uranium-235 as a nuclear fuel, there would not be a reprocessing cycle in which to efficiently produce plutonium-239. So today, we fuel our power plants with nuclear dynamite that creates waste products that last for thousands of years and rank among the most toxic substances in existence… for the primary purpose of building nuclear arsenals. We have corrupted the most powerful energy source that we have ever discovered and ignored its true potential to make a better world, all so we could feed the war machine and instead ensure our future allows us to do this:
In the face of such reckless disregard for our civilization and the lives of the people within it, words seem insufficient to describe what thoughts come to mind, especially since most of them are unfit for print. However, they should come with the realization that in spite of our current approach to nuclear energy, we do not have to keep doing this anymore. That’s where thorium comes in.
Thorium-232 in LFTRs can be compared to our current use of uranium-235 in Pressurized Water Reactors in the sense that they are both sources of nuclear energy. But in terms of operation and effectiveness, in reality it would be like comparing a spinach salad to a 4,000-calorie cheeseburger because they’re both food items. This is because thorium fuel and the reactor designs associated with it systematically avoid nearly every complication we experience with Pressurized Water Reactors, while at the same time providing a long list of benefits.