Environmental impact of nuclear power

Nuclear power has raised much public concern. Under normal operation, a nuclear power plant releases very little contamination of any sort to the environment. It does produce radioactive waste of several sorts. Moderate amounts of low-level waste are produced; this can be disposed of simply by placing it somewhere it won't be disturbed for a few years. However, a relatively small amount (perhaps a ton a year from a large nuclear power plant) of high-level waste is produced, and this poses a significant disposal problem. It can be expected to be dangerous for tens or hundreds of thousands of years (Taking 10,000 years to decay to activity levels below that of the original ore), so extremely secure disposal methods must be found. Currently, most such waste is stored in temporary storage facilities which require constant care and attention. Several methods have been suggested for final disposal of the waste, including deep burial in stable geological structures, transmutation, and removal to space. Some nuclear reactors, in particular the Integral Fast Reactor, have been proposed that use a different nuclear fuel cycle that avoids producing waste containing long-lived radioactive isotopes.

Accidents at nuclear power plants pose a risk of severe environmental contamination. The Chernobyl accident at an RBMK reactor, for example, released large amounts of radioactive contamination, killing many and rendering a large area of land unusable for the next few centuries. However, the power plant at Chernobyl was built with minimal concern for safety; modern nuclear power plants are much less likely to have such problems. The potential for such an accident still exists; however, many citizens are still concerned about the use of nuclear power. But their concerns should be weighed against the need to address the threats posed by climate change and the opinions of the broader community. This danger has received significant coverage in the popular press, so the public has a very strong fear of nuclear power (by contrast, the radioactive contamination due to coal burning is virtually unknown, as are most of the hazards of other methods of electrical power generation).

Nuclear power can also pose the risk of nuclear proliferation. Fission products can be reprocessed out of spent reactor fuel and diverted to a weapons program, or a reactor can be used to produce weapons materials through transmutation by direct irradiation by neutrons.

Effluent emissions

Commercial nuclear power plants release gaseous and liquid radiological effluents into the environment as a byproduct of electrical generation, which are monitored in the US by the EPA and the NRC. Dose to a unaffiliated member of the public as a result of these emissions is typically on the order of 0.01 mrem.

The total amount of radioactivity released through this method depends on the plant, regulatory requirements, and plant performance. Atmospheric dispersion models combined with pathway models are employed to accurately approximate the dose to a member of the public from the effluents emitted. Limits for the Canadian plants are shown below:

Regulatory limits on Radioactive Effluents from Canadian Nuclear Power Plants

Effluent	Tritium	Iodine-131	Noble Gases	Particulates	Carbon-14
Units	(TBqb × 104)	(TBq)	(TBq-MeVc × 104)	(TBq)	(TBq × 103)
Point Lepreau Nuclear Generating Station	43.0	9.9	7.3	5.2	3.3
Bruce Nuclear Generating Station A	38.0	1.2	25.0	2.7	2.8
Bruce B	47.0	1.3	61.0	4.8	3.0
Darlington	21.0	0.6	21.0	4.4	1.4
Pickering Nuclear Generating Station A	34.0	2.4	8.3	5.0	8.8
Pickering B	34.0	2.4	8.3	5.0	8.8
Gentilly-2	44.0	1.3	17.0	1.9	0.91

Indirect carbon emissions

Generation from nuclear power also does not directly produce carbon dioxide, which has led some environmentalists to advocate increased reliance on nuclear energy as a means to reduce greenhouse gas emissions (which contribute to global warming). Non-radioactive water vapor is the significant operating emission from nuclear power plants.

According to a 2007 story broadcast on 60 Minutes, nuclear power gives France the cleanest air of any industrialized country, and the cheapest electricity in all of Europe.

Like any power source (including renewables like wind and solar energy), the facilities to produce and distribute the electricity require energy to build and subsequently decommission. Mineral ores must be collected and processed to produce nuclear fuel. These processes either are directly powered by diesel and gasoline engines, or draw electricity from the power grid, which may be generated from fossil fuels. Life cycle analyses assess the amount of energy consumed by these processes (given today's mix of energy resources) and calculate, over the lifetime of a nuclear power plant, the amount of carbon dioxide saved (related to the amount of electricity produced by the plant) vs. the amount of carbon dioxide used (related to construction and fuel acquisition).

A life cycle analysis centered around the Swedish Forsmark Nuclear Power Plant estimated carbon dioxide emissions at 3.10 g/kWh and 5.05 g/kWh in 2002 for the Torness Nuclear Power Station. This compares to 11 g/kWh for hydroelectric power, 950 g/kWh for installed coal, 900 g/kWh for oil and 600 g/kWh for natural gas generation in the United States in 1999.

UK Parliamentary Office Study

In a study conducted in 2006 by the UK's Parliamentary Office of Science and Technology (POST), nuclear power's lifecycle was evaluated to emit the least amount of carbon dioxide (very close to wind power's lifecycle emissions) when compared to the other alternatives (fossil oil, coal, and some renewable energy including biomass and PV solar panels). In 2006, a UK government advisory panel, The Sustainable Development Commission, concluded that if the UK's existing nuclear capacity were doubled, it would provide an 8% decrease in total UK CO₂ emissions by 2035. This can be compared to the country's goal to reduce greenhouse gas emissions by 60 % by 2050. As of 2006, the UK government was to publish its official findings later in the year. On 21 September 2005 the Oxford Research Group published a report, in the form of a memorandum to a committee of the British House of Commons, which argued that, while nuclear plants do not generate carbon dioxide while they operate, the other steps necessary to produce nuclear power, including the mining of uranium and the storing of waste, result in substantial amounts of carbon dioxide pollution.

Storm and Smith publication

The report by Jan Willem Storm van Leeuwen and Philip Smith with the title Is Nuclear Power Sustainable? was prepared for circulation during the April 2001 United Nations Commission on Sustainable Development meeting, and again during the continuation in Bonn in July 2001. The report concluded that nuclear power is not sustainable because of increasing energy inputs. The report has been widely cited in arguments against nuclear power.

The report claims carbon dioxide emissions from nuclear power per kilowatt hour could range from 20% to 120% of those for natural gas-fired power stations depending on the availability of high grade ores. The study was strongly criticized by the World Nuclear Association (WNA), rebutted in 2003, then dismissed by the WNA in 2006 based on its own life-cycle-energy calculation (with comparisons). The WNA also listed several other independent life cycle analyses which show similar emissions per kilowatt-hour from nuclear power and from renewables such as wind power.