Basically, if a :Uranium Cell: has any components next to it that can take heat, the :Uranium Cell: will dump all of its heat into those components and dump none of its heat into the hull. Meanwhile, the only components that interact will hull heat are :Intergrated Heat Dispenser: . Thus, the components in this reactor do not interact at all with the hull heat. They don't draw heat away from the hull, and they don't dump heat into the hull. They just store the heat in their internal heat storage. Thus the hull (pre-heated to 9000 heat, of course) stays at the same heat at all times.
The reason this is difficult to understand is because most reactors use large numbers of :Intergrated Heat Dispenser: as a way of coupling the hull heat to the heat of every component in the core. The concept that components might not share their heat with the hull is an uncommon one, despite the fact that most components operate in this way.
Actually there is another component that reacts directly with the hull. Each Depleted cell is giving off 1 heat every second, which goes straight to the hull. To compensate this, some external cooling needs to be provided (-1 for each cell being charged).