President Donald Trump on Friday signed orders meant to accelerate the construction of nuclear power plants, including small, untested designs that offer the promise of rapid deployment but have yet to be built in the US.

Trump, who said nuclear power had become “a hot industry” and “very safe and environmental” just before he signed the orders in the Oval Office, did so flanked by Secretary of Defense Pete Hegseth and Interior Secretary Doug Burgum, the latter of whom said the signing marked “a huge day for the nuclear industry.”

Among a flurry of executive actions, Mr. Trump directed the nation’s nuclear safety regulator to speed up approvals for new reactors.