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Green House Gas Emissions of Light Water Reactors

[|Light Water Reactors] are the most abundant reactors found in nuclear power plants. LWRs are commonly used because of their low green house gas emissions. The two types of greenhouse gas emissions involved with LWR power plants are upstream and downstream. The upstream emissions figures are made up by how much greenhouse gas is emitted in order for the power plant to be built and produce energy. For nuclear power plants, these figures mostly depend on the greenhouse gases emitted from the uranium enrichment process. The downstream greenhouse gas emissions figures are derived from the emissions released during the decommissioning of power plants and the waste disposal process. The upstream green house gas emissions of nuclear power plants, utilizing Light Water Reactors, ranges between 0.74 and 1.3 grams in equivalent carbon dioxide emissions per kilowatt hour of energy (eq/KWh) and produce about 0.46 and 1.4 grams of eq/KWh of downstream emissions. Fossil fuel power plants produce between 1.5 and 20 grams of eq/KWh for upstream emissions and between 2.8 and 24 grams of eq/KWh of downstream emissions. Land based wind turbines produce between 8 and 30 grams of eq/KWh of emissions. Lastly, hydroelectric power plants produce between 1 and 34 grams of eq/KWh. Figure 1 compares this data to the green house gas emissions of fossil fuel, hydroelectric, and wind based power plants. [1]




 * Public Opinion

The results in Figure 2 are from a survey taken by the Center for Survey Research at the Eward J. Bloustein School of Planning. The survey was conducted during the time period from June 26, 2008 to August 22, 2008. From Figure 2 one can see that the data shows that the public opinion supports mostly solar and wind power as the preferred power of the future in the United States. [2]



1.	I.N. Kessides, “Nuclear Power: Understanding the economic risks and uncertainties”. Elsevier Ltd., Washington, D.C., Economic Review, 2010. Available: http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V2W-4YVP19F-1&_user=2403224&_coverDate=08%2F31%2F2010&_rdoc=1&_fmt=high&_orig=search&_origin=search&_sort=d&_docanchor=&view=c&_acct=C000057194&_version=1&_urlVersion=0&_userid=2403224&md5=67d5efe675a454d6d6bac86941386499&searchtype=a

2.	M. Greenberg, “Energy sources, public policy, and public preferences: Analysis of US national and site-specific data”. Elsevier Ltd. 2009. Available: http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V2W-4W84GTR-4&_user=2403224&_coverDate=08%2F31%2F2009&_rdoc=1&_fmt=high&_orig=gateway&_origin=gateway&_sort=d&_docanchor=&view=c&_searchStrId=1669019918&_rerunOrigin=google&_acct=C000057194&_version=1&_urlVersion=0&_userid=2403224&md5=86a9888c059b97d51217759cbdc893c3&searchtype=a#secx11

http://en.wikipedia.org/wiki/Radioactive_waste (Add On)

Space Waste Disposal

Space waste disposal is one solution to long term disposal of nuclear waste. The proposed method utilizes a laser launching system to send the waste into space. The nuclear waste would be encapsulated and launched into an orbit about 1,000 kilometers above Earth, a safe distance where it would be centuries before any capsules could re-enter Earth’s atmosphere. A space tug, which is a container used to carry payloads in space, would contain nuclear waste capsules and be equipped with a solar sail to bring these capsules to orbit around the sun, where the radioactive waste would no longer be an issue or a threat to re-enter Earth’s atmosphere. There are three technologies that are being considered for use in this ground based launch system, laser, microwave and electromagnetic railguns. However, laser based systems are the most promising in the near future. In this laser system, the laser will impact the bottom of the capsule and the heat from the impact will compress and explode the air, shooting the capsule into orbit. Lasers are a more favorable solution to use of rockets because of the decrease chance of accidents occurring. This system would solve the issue with long term storage of nuclear waste being a risk to future generations. [67]


 * Safety

The two components involved with a laser launch system are the operation of the system and the public perception. The laser system is safer than a rocket based system because since there are not rocket propellants and propulsion systems there is no risk of explosion. The only risk with lasers is if the laser fails before the capsule reaches the velocity needed to escape Earth’s atmosphere. The capsule will be bullet shaped so that the ballistics is very familiar and trajectories of the capsules are predictable. The capsules are designed like bullets because if there was a failure the capsule would land only in known recovery zones, which would be located far from populated areas. The capsules also need to be developed to withstand atmospheric heating, aerodynamic loading and potential reentry accidents. Fortunately, the United States has already invested years and billions of dollars into developing such a capsule, nuclear warheads. The encapsulation used for nuclear warheads can be adapted to use for space disposal capsules. [67]
 * Economics

Space disposal will cost tens of billions of dollars to implement as a disposal method for nuclear waste. The United States federal government has already spent 8 billion to research underground disposal and is estimated the final cost to be about 60 billion. One of the benefits of developing a system like this is that it allows inexpensive access to space. Although the laser ground based system would be costly to develop the overall cost of operation is very low. Using a system like the one proposed would cost a surcharge of a fraction of a cent per kilowatt hour of electricity. This power can be easily generated by nuclear reactors and handle the operation cost of a ground based laser launch system. To determine if a laser launch system would be a feasible solution, worth investing large resources in, would only require the cost of a Las Vegas hotel or up to two days of the defense budget. What makes space disposal so attractive is that it eliminates the problem and does not create new ones for future generations. [67]

67. J. Coopersmith, “Nuclear Waste in Space”. Available: http://www.thespacereview.com/article/437/2