Isn't the reactor 1:1 - so where's the huge, huge tank of antimatter? We know the antimatter is in bottles and containment do-higgers and it's a bit smaller than the big tank. I think the linear intermix shaft in TMP is a big tube of scary antimatter, dilithium particles, and matter thats in perpetual reaction, with more reactants getting fed up the system. The whole thing is the reactor and the chain reaction starts at the bottom. It's not a matter/antimatter collidor, more like a big scary stew. Hence the radiation suits. =) And under normal conditions, the energy from that also feeds the impulse engine.
There's no connection between the impulse engines (other than normal EPS taps perhaps?) and the matter-antimatter reactor in the Enterprise-D, so perhaps they needed all that slush for the impulse engines.
I'm not saying the TMP Enterprise doesn't need tanks, I'm just saying there COULD be an in-universe explanation for why they aren't gigantic. Also... couldn't the tanks be above the main engineering area? Various cutaways I've seen have about a deck of high over most of that space.
There's no connection between the impulse engines (other than normal EPS taps perhaps?) and the matter-antimatter reactor in the Enterprise-D, so perhaps they needed all that slush for the impulse engines.
I'm not saying the TMP Enterprise doesn't need tanks, I'm just saying there COULD be an in-universe explanation for why they aren't gigantic. Also... couldn't the tanks be above the main engineering area? Various cutaways I've seen have about a deck of high over most of that space.