I've tested the reactor now in beyond reality now and it seems to work flawlessly. It takes a while before the reactor reaches its full output which it seems to do at about 1% hull heat. Then the output varies between rougly 1332 and 1352. Ive let it run for about 15 minutes and it does not seem to encounter any problems.
I've let it run for one and a half cycle now, no problem whatsoever. Think its safe to say that it's completly safe
This will likely be my reactor of choice for future for gregtech, vanilla reactors can't really compete. I will probably add the thorium reactor aswell just to have a use for it.