May 2, 2008

Scientists Question Case For Nuclear Power

Australian researchers are challenging the argument for nuclear power as a replacement for fossil fuels, citing rising greenhouse gas emissions from uranium mining.

The researchers said that over time the availability of high-grade uranium ore would decline, making the fuel less environmentally friendly and more costly to extract.

A substantial portion of nuclear power's greenhouse emissions occurs during the fuel supply stage, which includes uranium mining, milling, enrichment and fuel manufacturing. Carbon emissions also take place during the construction and decommissioning of manufacturing plants.

The scientists based their analysis on recent financial and technical reports, historical records and analyses of CO2 emissions. Experts say it is the first analyses to include detailed information on the environmental costs incurred along all points of the nuclear energy chain.

However, the report is likely to come under close scrutiny as governments around the world consider nuclear power as a way to meet future energy demands and reduce greenhouse gas emissions.

"Yes, we can probably find new uranium deposits, but to me that's not the real issue. The real issue is: 'what are the environmental and sustainability costs?'," lead author Gavin Mudd, from Australia's Monash University, told BBC News.

"New uranium deposits are likely to be deeper underground and therefore more difficult to extract than at currently exploited sites," he said.

Furthermore, Mudd said the average grade of uranium ore, which indicates its uranium oxide content and is a vital economic factor in mining, is likely to decline. And obtaining uranium from lower-quality deposits means digging up and refining even more ore.

Transporting a greater amount of ore will in turn require more diesel-powered vehicles, the major source of greenhouse emissions in uranium mining.

"The rate at which [the average grade of uranium ore] goes down depends on demand, technology, exploration and other factors. But, especially if there is going to be a nuclear resurgence, it will go down and that will entail a higher CO2 cost," Dr Mudd said.

The report concludes that uranium mining may require more energy and water in the future, releasing greenhouse gases in greater quantities.

Thierry Dujardin, deputy director for science and development at the Nuclear Energy Agency (NEA), told BBC News the analysis made an important contribution to clarifying nuclear energy's impact on CO2 emissions.

"It is the beginning of the answer to a question I have raised in many fora, including within the agency," he said, while adding that he did not fully agree with the conclusions drawn by the authors.

"Even in the worst case scenario for CO2 emissions, the impact of nuclear on greenhouse emissions is still very small compared with fossil fuels," he said.

Dujardin acknowledged that lower grades of ore might have to be exploited in the future, but said emissions from mining were only a small portion of those produced in the entire nuclear supply chain.

He remains confident that as the industry reinforces its exploration efforts new deposits would be found.

For example, the nuclear industry is carrying out research into recovering uranium from rocks used in industrial phosphate production, and technologies based on solvent extraction can be also used to obtain uranium from phosphate rocks.

Eventually, some predict that "Ëœfast breeder' reactor technology will increase by up to 50-fold the amount of energy extracted from uranium.


On the Net:

REPORT: "Sustainability of Uranium Mining and Milling: Toward Quantifying Resources and Eco-Efficiency"

Environmental Science & Technology

Monash University

Nuclear Energy Agency (NEA)