Heh, sorry I didn't mean to talk above anybody's head. "Ramp-up" might be my own moniker, I'm blanking on what the power increase term is. Gen-sync is shorthand for generator synchronization. It's when they flip the switch that connects the generator to the grid. Which, as Stuart van Onselen pointed out, you have to do at a specific time or bad things happen that typically cost a lot of money to fix.

As for supercritical, you do need the reactor to go supercritical for a short amount of time. Critical is when just enough neutrons are being generated to maintain the current power level. Less than that is subcritical, meaning the core is losing power. So to power up to 100%, the reactor goes into a tightly controlled supercritical state, generating more neutrons than needed. Those extra neutrons cause additional fission to occur, generating even more neutrons which in turn causes even more neutrons to be released. Thus, through a rather impressive juggling act, a reactor is brought to its rated 100% power level and maintained there.