i have to submit seminar on nuclear emission and energy
i do not know what i have to add.
can any body has this seminar ?
thanks

some brief explanation about the nuclear emission and energy

For decades nuclear power has been slated as being environmentally harmful. But with climate change emerging as the world's top environmental problem, the nuclear industry is now starting to enjoy a reputation as a green power provider, capable of producin g huge amounts of energy with little or no carbon emissions1. As a result, the industry is gaining renewed support. In the United States, both presidential candidates view nuclear power as part of the future energy . The US government isn't alone in its support for an expansion of nuclear facilities. Japan announced in August that it would spend $4 billion on green technology, including nuclear plants.


But despite the enthusiasm for nuclear energy's status as a low-carbon technology, the greenhouse gas emissions of nuclear power are still being debated. While it's understood that an operating nuclear power plant has near-zero carbon emissions (the only outputs are heat and radioactive waste), it's the other steps involved in the provision of nuclear energy that can increase its carbon footprint. Nuclear plants have to be constructed, uranium has to be mined, processed and transported, waste has to be stored, and eventually the plant has to be decommissioned. All these actions produce carbon emissions.

Critics claim that other technologies would reduce anthropogenic carbon emissions more drastically, and more cost effectively. "The fact is, there's no such thing as a carbon-free lunch for any energy source," says Jim Riccio, a nuclear policy analyst for Greenpeace in Washington DC. "You're better off pursuing renewables like wind and solar if you want to get more bang for your buck. " The nuclear industry and many independent analysts respond that the numbers show otherwise. Even taking the entire lifecycle of the plant into account nuclear energy still ranks with other green technologies, like solar panels and wind turbines, they say.
Life studies

Evaluating the total carbon output of the nuclear industry involves calculating those emissions and dividing them by the electricity produced over the entire lifetime of the plant. Benjamin K. Sovacool, a research fellow at the National University of Singapore, recently analyzed more than one hundred lifecycle studies of nuclear plants around the world, his results published in August in Energy Policy2. From the 19 most reliable assessments, Sovacool found that estimates of total lifecycle carbon emissions ranged from 1.4 grammes of carbon dioxide equivalent per kilowatt-hour (gCO2e/kWh) of electricity produced up to 288 gCO2e/kWh. Sovacool believes the mean of 66 gCO2e/kWh to be a reasonable approximation.



The large variation in emissions estimated from the collection of studies arises from the different methodologies used - those on the low end, says Sovacool, tended to leave parts of the lifecycle out of their analyses, while those on the high end often made unrealistic assumptions about the amount of energy used in some parts of the lifecycle. The largest source of carbon emissions, accounting for 38 per cent of the average total, is the "frontend" of the fuel cycle, which includes mining and milling uranium ore, and the relatively energy-intensive conversion and enrichment process, which boosts the level of uranium-235 in the fuel to useable levels. Construction (12 per cent), operation (17 per cent largely because of backup generators using fossil fuels during downtime), fuel processing and waste disposal (14 per cent) and decommissioning (18 per cent) make up the total mean emissions.

According to Sovacool's analysis, nuclear power, at 66 gCO2e/kWh emissions is well below scrubbed coal-fired plants, which emit 960 gCO2e/kWh, and natural gas-fired plants, at 443 gCO2e/kWh. However, nuclear emits twice as much carbon as solar photovoltaic, at 32 gCO2e/kWh, and six times as much as onshore wind farms, at 10 gCO2e/kWh. "A number in the 60s puts it well below natural gas, oil, coal and even clean-coal technologies. On the other hand, things like energy efficiency, and some of the cheaper renewables are a factor of six better. So for every dollar you spend on nuclear, you could have saved five or six times as much carbon with efficiency, or wind farms, " Sovacool says. Add to that the high costs and long lead times for building a nuclear plant about $3 billion for a 1,000 megawatt plant, with planning, licensing and construction times of about 10 years and nuclear power is even less appealing.

References
Solomon, S. et al. (eds.) Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (Cambridge University Press, Cambridge and New York, 2007); http://ipcc.ch/pdf/assessment-report/ar4...g1-spm.pdf
Sovacool, B. Energy Policy 36, 2950–2963 (2008).
Mudd, G. M. & Diesendorf, M. Environ. Sci. Technol. 42, 2624–2630 (2008).

Kurt Kleiner is a freelance science writer.