The United States is the single-largest producer of nuclear power in the world, accounting for approximately a third of global output. But the domestic nuclear sector is in severe decline, and the nuclear fleet is rapidly aging, with many of the nation’s reactors scheduled to be retired in the coming years. Reviving the sector could be a huge boon to national energy security and global climate goals, but building new plants is prohibitively expensive. In the past few decades, the United States has only built one new nuclear power plant,…