Well, This one is a very compact one.
Mind you, there will need to be a *LOT* of cooling towers. I am not familiar with the latest numbers on plutonium cell heat generation, so I can't tell you precisely how many, but I will tell you that once you calculate your Micro-Cycle time divided by your Cooling Cycle Time, you will need to multiply that number by (number of cooling cells / 2).
Since that one-chamber reactor has 8 cooling cells, you'll need 4 cooling towers * (Micro-Cycle/Cooling Cycle).
The cooling cycle on a 360k NaK or He cooling cell for that cooling tower is (360,000/120) or 3,000 seconds. Micro-cycle on that reactor with basic Uranium is going to be 1500 seconds, so if you were just using plain quad-uranium, you would need 8 cooling towers. However, Plutonium will probably significantly increase the amount of heat generated, and thus dramatically reduce your micro-cycle time, increasing the number of cooling towers you will need.