Nuclear Fuel Cycle
The Basic Ingredients
First, you need mildly-enriched uranium.
There are 92 naturally occurring elements but only one, uranium, has become the key to the operation of the nuclear fuel cycle. Natural uranium consists of three isotopes: uranium-238, uranium-235, and uranium-234. Uranium isotopes are radioactive. When uranium is mined from the earth it contains only about 0.7% uranium-235. Industrial processes enrich uranium by concentrating the amount of U-235 to 3% or more for use as reactor fuel. Uranium with more than 20% U-235 is called highly-enriched uranium (HEU).
An atom can be pictured as a small universe with a nucleus at its centre and electrons orbiting around it. The nucleus contains protons and neutrons. Each electron has a negative charge and each proton a positive charge; since there are an equal number of protons and electrons the atom the atom is neutral. Atoms of the same element have the same number of protons (the atomic number). However, the same element can have atoms with varying numbers of neutrons in their nucleus giving atomic species of different atomic weights known as nuclides. Thus for the key element uranium, the nucleus of uranium-235 has 143 neutrons and 92 protons and uranium-238 has 146 neutrons and 92 protons.
The nuclei of radioactive elements are unstable, meaning they are transformed into other elements, typically by emitting particles (and sometimes by absorbing particles). This process, known as radioactive decay, generally results in the emission of alpha or beta particles from the nucleus. It is often also accompanied by emission of gamma radiation, which is electromagnetic radiation, like X-rays. As radioactive atoms decay, alpha, beta and gamma rays are emitted. Alpha rays are heavy positively charged particles travelling at high speed (several kilometres a second). These rays emanate from heavy elements such as uranium, plutonium and americium. Beta rays are negatively charged electrons seven thousand times lighter than alpha particles. Gamma rays are electromagnetic radiation which emanates from most though not all radionuclides.
These three kinds of radiation have very different properties in some respects but are all ionizing radiation--each is energetic enough to break chemical bonds, thereby possessing the ability to damage or destroy living cells. Uranium-238, the most prevalent isotope in uranium ore, has a half-life of about 4.5 billion years; that is, half the atoms in any sample will decay in that amount of time. Uranium-238 decays by alpha emission into thorium-234, which itself decays by beta emission to protactinium-234, which decays by beta emission to uranium-234, and so on. The various decay products, (sometimes referred to as "progeny" or "daughters") form a series starting at uranium-238. After several more alpha and beta decays, the series ends with the stable isotope lead-206. (Source: Institute for Environment and Energy Studies)
Uranium is the principal fuel for nuclear reactors and the main raw material for nuclear weapons. Both radioactive U-235 and stable U-238 are found in naturally occuring uranium deposits. Traditionally, uranium has been extracted from underground and open pit mines. Over half of the world's production of uranium from mines is in Canada and Australia. Uranium is also mined in China, the Czech Republic, France, Gabon, India, Kazakhstan, Namibia, Niger, Russia, South Africa, Spain, Ukraine, the United States, and Uzbekistan.
Natural uranium has to be mined from the earth like any other natural element. Yet, unlike other natural elements, uranium is radioactive. As a result, every aspect of uranium production, from mining to transportation, has damaging environmental and health effects.
Uranium mining has scarred the landscape and affected areas in 16 countries with millions of tons of dangerous dirt called tailings. Uranium mining on indigenous and tribal peoples' lands has devastated local communities and environments in North America, Australia, Africa, and Asia. For every ton of uranium oxide produced, thousands of tons of wastes, or tailings, are left behind. Often the tailings are simply dumped on the land near the mine and left to the effects of the elements. Wind carries radon gas and radioactive dust from these tailings for many miles. Contaminated rainwater enters the soil, the watershed and, eventually, the food chain, endangering health. Indigenous peoples' lands have also been used to dump radioactive wastes and to test (explode) nuclear bombs both above-ground and below-ground, resulting in massive radioactive contamination.
In Northern Saskatchewan, Canada, where the world's largest and most concentrated known uranium reserves are located, routine releases and accidental spills of contaminated water from mining and milling operations have poisoned major fisheries and threatened the health and livelihood of indigenous communities.
In Niger and Namibia, uranium tailings are simply dumped on the desert sand, contaminating the air, food, and drinking water of nomadic tribes.
In the Southwestern U.S., mining wastes abandoned on indigenous peoples' land have damaged the health of their communities. It is little known that the second worst nuclear disaster in US history was the spilling of uranium mine tailings in the Rio Puerco River in New Mexico in the 1980s.
Dineh (Navajo) and other uranium miners in the U.S. have contracted cancers at a much higher rate than the general population (including a lung cancer incidence forty times greater than normally expected). They were not told about the dangers of radioactivity.
Tibetan people have been, without their knowledge, radiation-tolerance test victims at sites of Chinese-operated uranium mines and waste dumps.
In order to be used in a reactor, the uranium must be enriched, increasing the percentage of radioactive U-235 in the sample. For typical civilian power plants the uranium must be enriched so that it contains 3% - 5% of uranium-235.
After mining the uranium mineral is refined to uranium oxide, called yellowcake. This natural uranium is processed and then enriched. Numerous technologies have been developed to enrich uranium, such as gaseous-diffusion, centrifuges, and electromagnetic separation. All of these technologies require a large initial investment and large amounts of energy to operate.
Yellowcake has two forms of uranium: uranium-235 and uranium-238. Uranium-235 fissions (splits) readily. Its concentration in yellowcake is only 0.7%. For the common nuclear reactor (light-water) yellowcake is enriched to 3% uranium-235. To make bomb-grade fuel yellowcake is enriched to 90%. Before enrichment, yellowcake is converted to a volatile material called "hex" (uranium hexafluoride).
In the diffusion process hex vapour passes through thousands of membranes along a two kilometre tunnel. In the other process the vapour passes through hundreds of small ultra-high-speed centrifuges. Centrifuge plants are compact and so readily concealed. They allow a country possessing a plant to switch quickly from the production of reactor-grade to bomb-grade fuel.
Reprocessing is probably the dirtiest operation in the nuclear fuel cycle. Reprocessing is also the option that generates the largest amount of radioactive waste. The most dangerous of this waste is called high-level waste -- a liquid waste stream carrying chemicals used in reprocessing along with many radioactive isotopes from the spent fuel or other material. This high-level waste would be added to over 30 million gallons of liquid waste from past reprocessing already stored in underground tanks at SRS. Some of these tanks have leaked, and storage of the waste in this form poses risks of fire or explosion resulting from chemical reactions inside the tanks. Moreover, in January 1998, SRS officials acknowledged -- after over a decade of warnings and a half billion dollars in expenses -- that one of the techniques intended to help remove waste from the tanks is unsafe. A replacement technology may not be ready until 2005.
Reprocessing is a chemical reaction, which separates plutonium and uranium from fuel which has been irradiated in reactors. The plutonium is important for weapons production, while the uranium is basically a byproduct that can be recycled as fuel. Because reprocessing is also part of the civilian nuclear fuel cycle, reprocessing is a key link between civilian nuclear power and nuclear weapons production. Thus, the existence of a reprocessing plant is what gives a country the ability to produce plutonium for nuclear weapons. Therefore, any country that has operating reprocessing plants can be classified as a potential nuclear-weapons power (Makkhijani, Hu, and Yih, 1995, p 47-48).
Reprocessing is also extremely costly. The overall costs of spent fuel management and disposal ranges from approximately $130 billion to $240 billion for commercial reprocessing (Makhijani and Saleska, The Nuclear Power Deception: US nuclear mythology from electricity "too cheap to meter" to "inherently safe" reactors, 1999, p. 9). The countries that have commercial reprocessing plants include UK, France, USA, Russian Federation, Japan, and India. All five of the reprocessing programs are governmentally owned or subsidized. ( Makhijani and Saleska, p. 122). The countries with military plutonium separation sites include USA, Russian Federation, UK, France, China, India, Israel, and Pakistan.
Mixed Oxide Fuel (MOX)
MOX is part of the nuclear fuel cycle which is used in the civilian branch of nuclear industry. Plutonium is converted into uranium-plutonium oxide fuel (called Mixed Oxide Fuel) to use it in existing commercial reactors or in new reactors. Used nuclear fuel can then either be disposed of as waste or recycled. A nuclear reactor uses enriched uranium fuel to produce heat, which in turn generates electricity. MOX fuel is manufactured by blending uranium and plutonium powders to include 3-10% plutonium.
The conversion of MOX into weapons-grade plutonium metal is feasible (Kuppers and Sailer, 1994, p85). This use creates a new commercial - military link creating dual-use reactors. Companies such as BNFL are hiding this direct connection by claiming to partially destroy (or "burn") rather than create military plutonium (Makhijani and Saleska, p10, 1999).
The use of MOX has huge setbacks due to the high cost of creating MOX fuel. In addition to a serious security liability the majority of independent studies done in the US have indicated that plutonium is not an economically viable energy resource. These studies have found that it is cheaper to use uranium fuel instead of MOX fuel. Uranium has turned out to be far more plentiful and far cheaper than predicted at the dawn of the nuclear era (Makhijani and Saleska, 1999, p 166).
Furthermore, there are inherent conflicts of interests. The corporations involved in the disposition of plutonium by using it as MOX fuel are the very same corporations that have a stake in the commercial production of plutonium (Makhijani and Saleska, 1999, p175). This is clearly indicated by BNFL which both creates and cleans up nuclear materials. Westinghouse (BNFL owned) runs the majority of nuclear power plants in the US while Bechtel Corporation is involved in massive nuclear clean up in the US.
Nuclear Power Plants and their side effects
Inside a Nuclear Power Plant...
1. The yellowcake is broken into small pieces and put into long metal rods. The rods are collected into bundles.
2. The energy released from these bundles during fission is used to heat water, turning it into steam.
3. At this point, nuclear power plants function much the same as traditional fossil fuel plants. The force of the steam moves a turbinethat, in turn, powers a generator that creates electricity. All nuclear reactors rely on steam in this manner. There are different major types of reactors that create this steam in slightly different ways, such as: Boiling Water Reactors, Pressurized Water Reactors, CANDU reactors (Canada Deuterium Uranium, a type of pressurized heavy water reactor), and LMFBR’s (Liquid-Metal Fast-Breeder Reactor). For more information about the different types of reactors please visit http://hyperphysics.phy-astr.gsu.edu/hbase/nucene/reactor.html orhttp://www.chemcases.com/2003version/nuclear/nc-10.htm
4. The rate of fission is determined by the number of neutrons bombarding the uranium sample. In order to adjust the rate at which the steam is produced, control rods (which absorb neutrons) are placed within the bundles. More energy will be created the further the control rods are raised out of the bundles, since fewer "bombarding" neutrons will be absorbed. If the operator wishes to slow or stop fission, the control rods will be fully submerged in the bundles.
Side Effects of Nuclear Power Plants
Nuclear/radioactive waste consists of the broken down uranium fuel used during fission, as well as all the machinery used in the process and the nuclear plant itself. Since so much high intensity energy is released during fission, everything that has come into contact with that energy becomes embedded with radioactive elements. The break down of uranium creates elements such as cesium, strontium, and plutonium. Though not useful to the production of more nuclear energy, these elements are highly radioactive.
The Plutonium Free Future project assessed that by the year 2000, the nuclear industry had "created 201,000 tons of highly radioactive irradiated (used) fuel rods. The plutonium in the waste will remain radioactive for up to 240,000 years (12,000 generations) or more."
This means that any living thing coming into contact with plutonium waste during this long period of time will be exposed to potentially harmful radiation, so, "for that entire time it must be isolated from all living organisms and from the water, land and air upon which they depend." However, there is no long-term solution for its disposal or storage. Short-term solutions do not address the grave health and environmental effects of nuclear waste that last for hundreds of thousands of years."
Toxic and nonradiological hazards, such as acids, solvents, nitrates, oils, heavy metals, fluorides, explosives, mercury, beryllium, and asbestos, are also products of the nuclear weapon legacy that have negatively affected public health and the environment.
Nuclear waste is particularly devastating since there is no long-term solution for its disposal or storage. Short-term solutions do not address the grave health and environmental effects of nuclear waste that last for for hundreds of thousands of years. Generally, nuclear waste is dumped in low-population areas of the world ranging from Australia to Kentucky. To see a map of U.S. states that have agreed to be nuclear waste disposal sites see: http://www.hsrd.ornl.gov/nrc/rulemaking.htm
Dangers of Nuclear Reactors. As if the problems and dangers posed by nuclear waste weren’t enough, the very existence of nuclear reactors creates a serious threat to our environment and our health. As stated in A Race Against Time, the 1978 Report on Nuclear Power by the Royal Commission on Electric Power Planning, “when we talk about the safety of a nuclear reactor, we are referring essentially to how effectively the fantastic amount of radioactivity contained in the reactor core can be prevented from escaping into the ground and atmosphere in the event of major malfunctions” (http://www.ccnr.org). Yet, as we have already seen in the past few decades, major and minor malfunctions in nuclear reactors can have catastrophic consequences. Here are two examples of recent nuclear reactor malfunctions.
Chernobyl. On April 25th and 26th 1986, the world experienced the worst nuclear power accident in the history of atomic technology. During a routine test of Reactor Four, the reactor experienced two explosions within two minutes of each other as a result of mechanical flaws and operational failures. As a result, at least five percent of the radioactive reactor core was released into the atmosphere, first blanketing Northern Europe, then the rest of the world. The dire health and environmental consequences are still being revealed to this day. For more information about the Chernobyl accident please see: http://www.wagingpeace.org/menu/action/urgent-actions/chernobyl/
Three Mile Island. Due to mechanical and operational failures, this nuclear power plant on Pennsylvania’s Susquehanna River experienced a partial meltdown on March 28, 1979. The extent of the damage and the amount of radioactivity released into the environment during that period is still disputed in the scientific community. Even so, the events at Three Mile Island illustrate how quickly a functioning nuclear reactor can deteriorate into a near meltdown. It also reveals the life threatening consequences of basic human error on the part of even the best-trained nuclear technicians. For more information about the chronology and aftermath of Three Mile Island, please see http://www.washingtonpost.com/wp-srv/national/longterm/tmi/tmi.htm, orhttp://www.pbs.org/wgbh/amex/three/sfeature/index.html
For more information on the dangers of nuclear reactors, please visit http://www.ccnr.org/#accident
For more information on the ramifications of nuclear energy, please visit: http://www.thebulletin.org/article.php?art_ofn=ja00abrahamson
There are correlations between nuclear energy technology and nuclear weapons technology. Not all states developing nuclear energy technology have the intention to use that technology for weapons. Yet, once the technology and machinery for creating nuclear energy are gained, it is possible to begin developing weapons technology. Uranium for civilian use needs to be enriched to >5%. Military use uranium needs to be enriched to >90%. (http://www.ieer.org) While this discrepancy is great, a person or State with the technology to enrich uranium for energy has the potential to move towards weapons development.
Another relationship between nuclear energy and nuclear weapons is the ability to “recycle” spent atomic fuel, in the form of plutonium, into weapons technology. Uranium can produce plutonium during fission.
During the operation of a reactor, some uranium-238 is converted to plutonium-239. Periodically spent-fuel is removed from reactors and after storing for a year or more it can be treated in a reprocessing plant to recover the plutonium, the essential ingredient of the nuclear bomb. Only 8 kilograms of plutonium (the size of a large orange) is needed for an explosion.
While other dangerous elements also occur, plutonium is important in that it can be used in nuclear weapons. “If the nuclear power reactor continues operating for a total of 30 years, it will have produced enough plutonium for at least 1200 bombs” (http://www.nirs.org/factsheets/PLUTBOMB.htm). For more information on “recycling” atomic fuel, please see http://www.nirs.org/factsheets.