Proponents of nuclear energy argue that nuclear power is a sustainable energy source which reduces carbon emissions and can increase energy security if its use supplants a dependence on imported fuels. Proponents advance the notion that nuclear power produces virtually no air pollution, in contrast to the chief viable alternative of fossil fuel. Proponents also believe that nuclear power is the only viable course to achieve energy independence for most Western countries. They emphasize that the risks of storing spent fuel are small and can be further reduced by using the latest technology in newer reactors, fuel recycling, and long-lived radioisotope burn-up. For instance, spent nuclear fuel in the United States could extend nuclear power generation by hundreds of years because more than 90% of spent fuel can be reprocessed. The operational safety record in the Western world is excellent when compared to the other major kinds of power plants.