That is Trump giving political favours and ignoring the fact...

That is Trump giving political favours and ignoring the fact that utilities have been turning to natural gas as a cheaper and cleaner burning option which gives on demand responsiveness like the other fuels. Claims of national security are nonsense since the US is awash in natural gas. A natural gas burning plant can be established in ever so much shorter time than a nuclear plant.
If Trump had appealed to climate change prevention as a reason to use nuclear then he would have made sense but of course he would have under-mined his previous stand on climate change in so doing.
As the Bloomberg articles states: "One likely plan...would favor certain power plants in the name of national security. Those plants are owned by some of the president’s political allies in the coal industry."
Politically based decisions nearly always lead to bad economic decisions and the appeal to national security for supply does not not stand up to examination either.