Five years ago, nuclear power was the energy source that Americans found least desirable. Now, it’s oil. A recent MIT survey of 1,200 Americans found that 35 percent want to see more use of nuclear power, up from 28 percent in 2002. Americans still have doubts about nuclear safety; only 28 percent of this year’s respondents agree that “nuclear waste could be stored safely for long periods of time.” But people seem more attentive to the cost and environmental impact of their energy sources, and they worry about the war in Iraq. The fraction who want to decrease oil use has jumped from 56 in 2002 to 74 percent today.