BOISE, Idaho—The U.S. Department of Defense is taking input on its plan to build an advanced mobile nuclear microreactor prototype at the Idaho National Laboratory in eastern Idaho. The department began a 45-day comment period on Friday with the release of a draft environmental impact study evaluating alternatives for building and operating the microreactor that could produce 1 to 5 megawatts of power. The department’s energy needs are expected to increase, it said. “A safe, small, transportable nuclear reactor would address this growing demand with a resilient, carbon-free energy source that would not add to the DoD’s fuel needs, while supporting mission-critical operations in remote and austere environments,” the Defense Department said. The draft environmental impact statement cites President Joe Biden’s Jan. 27 executive order prioritizing climate change considerations in national security as another reason for pursuing microreactors. The draft document said alternative energy sources such as wind and solar …