Nuclear power is dirty April 20, 2007Posted by Andreas in Environment, Nuclear Power, Sustainable Living.
Advocates of atomic energy love touting nuclear power as a source of clean and green electricity, but how clean is it really?
Below, is some information from the December 2006 issue of Elements – An International Magazine of Mineralogy, Geochemistry, and Petrology, which is published jointly by several North American and European scientific societies. The issue is entitled The Nuclear Fuel Cycle – Environmental Aspects and contains a series of articles by scientists who are described as “recognized leaders in their fields”.
Manufacturing fuel for nuclear power stations produces radioactive waste at every step of the process, but the largest volume of waste consists of mine and mill tailings (i.e. material that’s left behind after uranium ore has been mined and processed).
Mining of about 17 000 tonnes of 1% uranium ore is required to produce enough uranium to fuel a 1 GW(e) nuclear reactor for one year. To date, worldwide mining of uranium ore has generated approximately 938 million cubic meters of tailings from more than 4000 mines. In most cases, the tailings are disposed off by “near-surface impoundment” (i.e. burial) near the mine or mill.
With levels of radioactivity ranging from less than 1Bq/g to more than 100Bq/g, catastrophic or continuous release of contaminants from these disposal sites can have substantial impacts on the environment.
The principal radiation risks from uranium tailings are radon gas, windblown radioactive dust dispersal and gamma radiation. Mill tailings are also frequently associated with elevated concentrations of highly toxic heavy metals which are a major source of groundwater and surface water contamination.
Improper disposal of mill tailings in the past has led to substantial water and soil contamination and disposal sites with no effective containment of the tailings are widespread. Hundreds of incidents of containment failure, resulting mostly from slope instability, earthquakes, seepage and overtopping, have been reported (here’s an example that’s been in the news recently).
The most notorious of these sites is probably at Mailuu-Suu, the site of a former soviet uranium plant in Kyrgyzstan, which was recently voted to be one of the world’s ten most polluted places.
A typical 1GW(e) nuclear reactor generates approximately 20 metric tonnes of highly radioactive spent nuclear fuel waste per year. In the USA, the current “inventory” of this type of material stands at about 62 000 metric tonnes and is projected to at least double by the end of the operating life of currently active nuclear plants.
At the moment, there are 443 atomic energy plants in operation worldwide (with some 24 more under construction). The current global inventory of spent fuel is about 270 000 metric tonnes.
Proponents of nuclear energy argue that for atomic power to have a significant impact on greenhouse gas reduction, a three to ten-fold increase in worldwide nuclear electricity generation is necessary by 2050.
The ten-fold increase scenario requires about 3500 new 1GW(e) atomic power stations to be built, which would produce some 100 000 metric tonnes of radioactive spent fuel every year.
The three-fold increase scenario would involve a new 1GW(e) plant to be constructed every several weeks and the high level waste generated would necessitate opening a waste storage site similar to the one proposed at Yucca Mountain in the USA every three to four years.
There is currently no long-term disposal site for high-level nuclear waste anywhere in the world. About US$7 billion have already been spent on researching the viability of the proposed repository at Yucca Mountain (with an envisaged capacity of 70 000 metric tonnes equivalent of spent nuclear fuel), but the US government has not yet granted a license for this facility.
The point I’m trying to make here is, of course, that even though we are regularly told that nuclear energy is a very clean source of energy, this is certainly not the case if one considers the industry in its entirety.
The atomic energy industry generates wast amounts of toxic and radioactive waste that has already contaminated parts of our planet and much of which we have no idea what to do with as yet.
Doesn’t sound all that clean to me!