Car brand is owned by BMV. RR now is primarily known as a defence contractor and jet engine manufacturer (and other powerplants).

To answer your original question, Rolls Royce is a major job provider in the UK. This is probably an attempt to revive it in addition to building it. A lot of these are job programs first.

https://en.wikipedia.org/wiki/Rolls-Royce_Motor_Cars

More relevant for this case is that they are also involved in Submarine propulsion, which usually means nuclear. So I would guess that they have significant experience.

Still, I would be surprised if the US government commissioned a reactor from Pratt and Whitney.