Speaking at the Royal Society for the encouragement of Arts last week, Smith said the challenges of climate change and developing a low carbon economy meant nuclear power could not be ignored.
"If we are to have the remotest chance of meeting our 80% reduction target by 2050, we have to have more or less de-carbonised our electricity production completely by 2030," said Smith.
"We have to include new nuclear generation within the overall mix –and this means solving the major outstanding dilemma of how to find a safe and secure repository for our high-level and intermediate-level radioactive waste."
Smith also slammed environmentalists for saying that the only way to combat climate change was for everyone to turn into " green hippies living off the land".
"The problem is, it simply isn’t going to happen," he said.
"People won’t want to live their lives like this. It’s difficult enough to convince people to do something, however small, to help to avoid a disaster that is waiting to happen but hasn’t happened yet. To do so on the back of an unrelievedly doom-laden analysis isn’t going to persuade very many people. We need to learn the classic lesson that Barack Obama has re-taught us: tell it as it is, yes, but give a sense of hope that things could be made to be different. And that all we need is the will to do it."