i can't see why you would want to propose something that has no hope of being funded and is going to be really really hard to accomplish. how many heavy lift launches will be needed per year/ how many EVAs will be needed? where will these astronauts be housed while construction is going on? will launching a nuclear reactor be politically acceptable? Far better to use existing current technology, chemical rockets and no assembly in space, to reach mars first. then use that as a base to go further. I've been turned by zubrin.