Thanks guys for helping me figure this out.
So what I have discovered is that I can measure the core heat by simply watching the rate of ice consumption. Even though my reactor components were cool, the ice was continuously being consumed with no break. That means the core's heat was not being removed and it would eventually explode.
I have managed to put together enough pumps and compressors to bring my reactor up to about 350eu/t average by carefully judging how much ice I am producing. My Ice cache is just barely growing over time, so the next step now is to continue hunting for resources so I can build more pumps and compressors.
And I must say, having a massive underground room with about 22 pumps and 22 compressors in it with all those pipes, just to keep the reactor cool, IS REALLY COOL.