“There is no such thing as a zero or near-zero-emission nuclear power plant”. Stanford professor Mark Z Jacobson has said new nuclear plants may cost up to 7.4 times more than wind and solar facilities, with construction times longer by up to 15 years. Such a delay, he said, may see a huge amount of extra carbon emissions from fossil fuel power sources. Measuring carbon emissions from nuclear plants during operations does not take into account the horrendous carbon footprint caused during the lengthy waits for them to come online. With new nuclear projects taking so long – and utility scale solar or wind schemes requiring 2-5 years to begin commercial operations – nuclear effectively emits a hundred years’ worth of 64-102g of CO² per kilowatt-hour of plant capacity just from grid emissions during the wait for projects to come online or be refurbished, compared to wind or solar farms. Jacobson added, a further 2-4 years of plant downtime will have to be factored in to take account of the refurbishment required to ensure nuclear facilities run for their expected 40-year lifetime. “Overall, emissions from new nuclear are 78-178g CO²/kWh, not close to zero,” he wrote. “Even existing plants emit, due to the continuous mining and refining of uranium needed for the plant.
Thanks to Pete Roche of UK Nuclear News for this, gleaned from PV Magazine 18th April 2019