A new Albuquerque mixed-use neighborhood called Mesa del Sol, near the airport, is still under construction. But it’s coming together: earth-toned homes have popped up; rock-based snake sculptures line the medians. There’s also a road called Pacific Fusion Drive—and it now leads toward a construction site where a company of the same name broke ground on a $1-billion fusion research and manufacturing campus on a hot, dusty August day.The bigwigs in attendance—New Mexico’s governor and senators, Albuquerque’s mayor, and leaders from the nuclear establishment, among others—escaped the heat and dust inside a fancy air-conditioned tent with a carpeted floor. They…