I applied online, then took situation-judgement and numerical tests. This was followed by a competency-based phone interview ("Give me an example of a time when you've worked under pressure / come up with an innovative solution to a problem"). It took six weeks to hear that I had a face-to-face interview for a specific position at a nuclear site which I traveled to. On arrival I retook the numerical test. The interview was partly competency with some technical questions specific to the areas that I was interviewing for. The technical questions were reasonable enough but under the pressure of the interview I couldn't answer everything. The interviewers understand that you're nervous and that you're a student so just try to think through logically and explain your thought process (and it's ok to admit you don't know, I drew some blanks and still got an offer).