KEMMERER, Wyoming—In this sleepy Wyoming town that has relied on coal for over a century, a company founded by Bill Gates is launching an ambitious project to counter climate change: A nationwide reboot of nuclear energy technology. Until recently, Kemmerer was little-known for anything except J.C. Penney’s first store and some 55-million-year-old fish fossils in quarries down the road. Then in November, a company started by Gates, TerraPower, announced it had chosen Kemmerer for a nontraditional, sodium-cooled nuclear reactor that will bring on workers from a local coal-fired power plant scheduled to close soon. The demonstration project comes as many U.S. states see nuclear emerging as an answer to fill the gap as a transition away from coal, oil, and natural gas to reduce greenhouse gas emissions. Many residents in Kemmerer, where the population of 2,700 is little-changed since the 1990s, see the TerraPower project as a much-needed economic boost …