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Energy Alternatives: The Nuclear Fuel Cycle

The nuclear fuel cycle requires a series of complicated steps, each with its own set of risks.

 

Energy Alternatives: The President's Plan

In his latest Energy Bill sent to Congress, President Bush recommends, among other energy alternatives, expanding the use of nuclear power as a means of generating electricity in the United States. He, like other nuclear proponents, site nuclear power as a safe, environmentally friendly way of generating electricity that creates no greenhouse gases and addresses the problem of global-warming.

Since the partial meltdown at Three-Mile Island in 1979, the nuclear power industry has been fairly quiet. We've seen no serious problems operating nuclear power plants in the United States or Canada and the accident at Chernobyl was generally viewed as a problem linked to flaws in the Soviet design, construction, and operation of that plant. Many now agree nuclear power is among the cleanest, safest, most dependable energy alternatives.

Before we fully embrace the nuclear option and ramp up production of new plants, we need to know something about the Nuclear Fuel "Cycle." This is not a true cycle because it does not start anew where it ends as does, for example, the water cycle. Rather it creates highly radioactive end products that require permanent high-security storage facilities that are yet to be located and built.

 

NUCLEAR FUEL CYCLE …Reference: Uranium Information Centre

MINING--Uranium is a naturally occurring element found in some rocks, which means it is accessed by mining. Although waste containment and mine reclamation has improved, surface mining remains among the most environmentally disruptive activities we humans do. Vegetation is stripped off the ground and usually burned. Topsoil that in some cases has taken thousands of years to form is scraped away along with the rest of the unwanted rock collectively known as "overburden" to get at the desired coal, oil shale, or metallic ore below. The waste rock needs to be stored somewhere, generally a low spot in the landscape, which is sometimes a stream valley in the coal country of West Virginia, or a wetland or lake in the Iron Range of Northern Michigan.

 

Certain mineral compounds that are stable under anaerobic (low oxygen) conditions under ground undergo "weathering" once exposed to the earth's surface, forming new compounds. One example of this process is the weathering of sulfide minerals to form sulfate compounds, including sulfuric acid, to cause a serious environmental hazard known as Acid Mine Drainage.

 

Aquifers and groundwater flow are often disrupted requiring nearby residents to find alternative water sources. In court, culpability in groundwater cases is often hard to prove so that expensive litigation, if people can afford it, drags on or breaks off with no clear resolution. Energy alternatives that require mining, including coal, uranium, and oil shale, come with high environmental costs. The Surface Mine Reclamation Act (SMCRA) addresses the need for mine reclamation, but this is an expensive process that, at best, only partially replaces the former functions and values of the pre-existing water and biological resources.

 

In North America, uranium surface or "strip" mines are generally found in the dry western states and provinces and there is always the issue of radioactive dust inhalation for the miners and anyone else downwind. The dust and waste rock contain concentrations of uranium that are too low for economically feasible extraction, but enough to leave the spoils radioactive and hazardous. The extent of the hazard is unclear but the hazard remains for tens of thousands of years. It is difficult to prove that something like mine dust gives us cancer. Tobacco and a lot of other things cause cancer, too.

 

MILLING--Either at the mine or somewhere nearby, the rock containing the uranium ore is ground into a fine powder (more dust) and mixed with sulfuric acid to separate the Uranium from the other rock minerals. The end product of this process is a commercially valuable material enriched in Uranium oxide called "yellowcake."

 

CONVERSION AND ENRICHMENT--Conversion is a process whereby yellowcake is converted into a gas called uranium hexaflouride. Enrichment refines and concentrates the isotope uranium-235 to make fissionable material, that is, a material with enough critical mass of highly radioactive uranium isotopes such that a nuclear fission reaction can occur. The fission reaction releases an enormous amount of heat, (and other hazardous nuclear decay products) which, in the case of a nuclear power plant, is used to boil water and make steam, drive a steam turbine, and generate electricity.

The enrichment process can create material for use in power plants, but it is also the stage at which bomb-grade uranium can be produced.

 

FUEL ROD ASSEMBLY--Once the uranium is enriched and pelletized, it is packed into metal tubes that are then loaded by the hundred into a nuclear reactor core.

 

POWER PLANT OPERATION AND MAINTENANCE--Operation and maintenance of a nuclear power plant is highly technical and involves high security. The fuel rods wear out and must be stored. The plant has to BE shut down to take out the old rods and replace them. The old rods, still highly radioactive, are temporarily stored in "swimming pools" to keep them cool and prevent them from catching fire. Plutonium, a bi-product (daughter element) of the uranium radioactive decay process, is found in the spent fuel rods and can be used to make nuclear weapons.

 

REPROCESSING--A portion of the material in the spent fuel rods can be recovered and reprocessed to make more fissionable uranium fuel or a mixture of uranium and plutonium fuel that may be used again in power plants.

 

LONG TERM STORAGE--Not all of the radioactive waste can be re-processed, however, and must be stored long-term. The current technology involves imbedding the waste into glass and encasing the glass in stainless steel canisters that require further shielding during transport to some temporary storage facility. This is currently the last step in the "cycle." No permanent storage arrangements exist at this time.

 

TRANSPORTATION--A note about all of the above processes: they do not happen all in the same place. Therefore, the materials are in the transportation stream, travelling in some cases very long distances to get to the next stage of the process.

 

COMMENTS

 

NUCLEAR TERRORISM

 

 

Other Recommended Links:

SMC Wind Power Page

Energy Alternatives - American Wind Energy Association

Enviro-Friendly Products: Tools for Sustainable Water and Energy Systems

Keywords: energy alternatives, nuclear fuel cycle, fuel fabrication, nuclear waste, uranium mining.   

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