Why not use the 360k cooling cell? Сells do not cool the reactor with automatic replacement cell.
Cooling takes only 360 000EU, and 3 minutes. (Full A.E.S.U ~ 50% of the heat 360k)
Efficiency at temperature 96,896 (of 96,900) ~ 1 Quad MOX Cell 2386EUt
Increasing the temperature is better than the use of neutron reflectors.
Sorry for the google translation.