I saw NuclearCraft has this on the Roadmap, but as i didn't know when i'd like to suggest it again.
It'll be much fun to have Steam coming out, which can then be reprocessed by Mekanisms Steam Turbine into electricity. This will make cancelling the Mekanism Fusion Reactor much easier, giving an extra layer of complexity and reality.

Also, well - i do not know - but shoudln't it be pretty easy to give the Reactor a steam Output instead of electricity? You woudln't Need to add steam turbines for the meanwhile, as there are many mods out there that do and could just be a config Option if one does like steam or direct electricity for now.

Steam producing, molten salt fission reactors and steam turbines are on the to-do list :)

So, just an update on this - alpha builds for the molten salt reactor have been released on the Discord server. Currently there are no heat exchangers or steam turbines, so no way to use the heat of the fission reactions to generate energy, but you can still play around with designing reactors. Seems pretty stable so far and there are no outstanding bugs yet :)

The basic process is:

1. Molten salt fuel in reactor fission vessels -> heat and depleted fuel
2. Coolant in reactor heaters -> hot coolant
3. Hot coolant + water in heat exchanger -> coolant + high pressure steam
4. High pressure steam in high pressure steam turbine -> energy + exhaust steam
5. Hot coolant + exhaust steam in heat exchanger -> coolant + reheated steam
6. Reheated steam in low pressure steam turbine -> energy + low quality steam
7. Low quality steam in condenser -> water

There will be a config option to allow for the heat exchanger to produce normal steam for use in Mek and ER turbines if wanted :)

Oh yes, the total energy output will be worth it - it won't be a ridiculous amount better, but definitely a good option if you have a lot of resources :)

Steam production has been added in v2.12 :)