Mission to send a reactor to space

[Kass_Is_Legend]

maybe if one day we can get cubes and or blocks in KSP i might be able to build a RBMK-1000 graphite moderated water cooled reactor and load it onto a falcon heavy and send it into a low earth orbit

[Incarnation of Chaos]

Why do you want to make Chernobyl in space? Why?

Also just get Nertea's excellent Near Future Electrical if you want Nuclear Reactors, and then there might be a way you could use contract configurator to make a set of contracts specifically for them (Not entirely sure about this myself though).

[Gargamel]

If you're looking for minecraft in KSP, it's already in the game, came out in not so recent update:

 

But seriously, KSP is already a lego style building game.  We already have blocks and trusses and struts and generic building shapes.    Take a look at the fan works for some of the awesome creations people have created with the tools already in the game.