I applied online. The process took 1 day. I interviewed at Rolls-Royce (Derby, England) in Jul 2012
Interview
-Maths test
-Pattern reasoning test
-Technical interview
[Make sure you know the basic of how a nuclear power plant works both physics & mechanics(slow neutrons etc)]
[You also have to pick a topic off a generic list to explain (a lot are obviously aerospace related - despite it being a nuclear interview) eg explain upthrust on a plane wing]
-Compentancy interview
[A few basic questions (why RR, RR in the news, threats/opportunities etc). Presentation about self prepared beforehand. Talk about your CV.]