No, the reactor only takes one item out of a stack per reactor tick. You need enough stacks to cool the heat added each reactor tick.
I initially thought as you do that a number of ice would be consumed in a stack but that ended up in lava, fire and other hilarity.
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Another thing though about these snow golems... They where added after MC 1.9 and IC2 buffed ice in 1.337 (prior to the 1.0.0 port) and now i am starting to think that ICE is OP with Snow Golems capable of creating it soo freely.
But then again, EE fed reactors are also OP... Except, Snow Golems exist in vanilla minecraft and as such has to exist in all games with IC2 in it.