As of right now, numbers go like:
Basic reactor chambers are the same as always.
Heat Capacity Reactor Chamber adds 500 each to the max heat but reduce the blast resistance by 5% each.
Containment Reactor Chambers add 10% blast resistance each, but decrease the max heat by 200 each.
Infernal Reactor Chambers add 750 max heat each, and add 10% blast resistance each.
Reactor cores go like:
Type A (tier 1) max heat 10,000 (same as before), 0% blast reduction
Type B max heat 12,000, 5% blast reduction
Type C max heat 14,000, 15% blast reduction
Items:
Quartz Condensator can absorb 50,000 before breaking.
It can be repaired (doesn't show up in NEI yet):
Condensator + redstone = +4000 durability
Condensator + quartz = +20,000 durability
Obsidian Neutron Reflector has a durability of 50,000 (standard thick reflector is 40,000)
Thick Obsidian Neutron Reflector has a durbility of 200,000
(these things can outlast uranium cells)
The Infernal Reactor Vent can vent up to 16 heat per reactor tick. And it can expel 10 bonus heat by spawning a fire nearby or 40 bonus heat by spawning something worse(what could it be). The bonus heat is expelled randomly with a higher chance if the vent is more damaged.
I hope that helps.