Since convection depends on absolute height, reactors relying on convection have a certain minimum height. Roughly speaking. So if you scale a reactor down, at

Since convection depends on absolute height, reactors relying on convection have a certain minimum height. Roughly speaking. So if you scale a reactor down, at some point it becomes very skinny and that might lead to problems. Anyway, 60 megawatts electricity is not too big in my opinion.