The U.S.'s last big nuclear-power project came in more than $16 billion over budget and seven years behind schedule. Now, the U.S. government wants to give the AP1000 another shot. President Trump is betting $80 billion that the U.S. can revive the stalled nuclear power industry—and make large reactors, like the AP1000 from Westinghouse Electric, a ubiquitous power source rather than a cautionary tale. U.S. electricity demand is rising across the country, partly thanks to the frenzy over artificial intelligence, after remaining flat for decades...