WASHINGTON — The US Army last week made it official: nuclear microreactors are coming to US bases, thanks to roughly $2.2 billion spread across five companies.

The goal of the Janus program is to produce 20 prototypes that will be contractor owned and operated at five bases, with the first one up and running by fall of 2028. And the reason for this move, officials said, should be self-evident.

“Unlike in prior conflicts, we now know that our domestic electric grid is potentially at risk in a conflict,” Jeff Waksman — the principal deputy assistant secretary of the Army for installations, energy and environment – told reporters during a call on Wednesday. “We also know that we will not necessarily be able to move fossil fuels easily wherever we need them to go.”

But while the reasoning may be clear, there are still a number of questions about how, exactly, this effort is going to play out. After all, nuclear physics aren’t famous for being simple, as Waksman himself noted.

“We know that this is going to be very difficult, and that there’s a very real chance that one or more of these [Janus program] companies will fail,” he said.