Your reactor is Mark II-1 C
Ashenwolf calculates heat correctly. But using time-unit "ticks" isn't good, because Game has 20ticks per second, but "reactor" recalculates heat only 1x per second. Mixing game ticks and reactor ticks is bad. Much better is use for reactor time-unit: seconds.
Uranium cell lifetime is 10000 "reactor ticks" (or 200000 game ticks) = 10000s
Your reactor has +35 heat/sec.
After full uranium cycle he accumulates 35*10000 heat and distributes between 1x hull, 14x HD, 30x coolant cell = 45 elements
35*10000/45 = 7777 heat in each coolant cell, HD and hull. Then needs cooldown before next cycle.
Would this make a good breeder then? I could use the configuration I have to heat it up to 7777 while getting good power out of it, and then I could hopefully figure out 2 coolant cells to take out and put 1 u-cell in the middle with 4 surrounding it right?
How much does one lava bucket heat up the system? Should I put some in near the endo f the cycle to push it to 9000?