How likely is it to become our main power source by 2050? Rather unlikely, as unfortunately there's still a lot of money going into less efficient kinds of energy.
How beneficial would it be? Absolutely ideal! Nuclear power is the safest, cleanest large-scale energy source out there. People need to stop thinking it's risky or bad for the environment. Any accidents involving nuclear power plants were entirely due to lack of care or mishandling of equipment - a properly mantained nuclear reactor will practically never have any issues. Fukushima was a direct result of limiting nuclear expansion in the sense that it was an old-style reactor, pushed well past it's service life, because Japan has a moratorium on building new plants. Chernobyl was a cold war result (RBMK reactors are built to generate weapons-useful waste leading to a remarkably bad design plus neglect). Even then, it doesn't reach a fraction of the damage caused by oil spills, mining accidents, dumping hundreds of tons of CO2 into the atmosphere, and all the other problems with fossil fuels. Nuclear byproducts are collected and led to appropriate isolation rather than ejected into the air or water - it's safer to live near a nuclear plant than a coal plant.
Check
this out. Now, for comparison, Chernobyl caused 15 deaths and
max 4000 cancer cases in the following 80 years. Even if we had 5 Chernobyl-scale nuclear plant accidents every year - an absurd scenario - it
still would be better than using fossil fuels. Nuclear power prevented approximately 1.8 million deaths between 1971-2009 as a result of lower air pollution
according to NASA, and that doesn't even count thousands of potential deaths from coal mining (one of the most dangerous professions in the world). And all of that is only accounting current technology, as reactors become increasingly more efficient and safer; that will be especially true when the ball really gets rolling on fusion.
People need to realize that, to prevent increasing amounts of deaths and environmental issues, we have to get pollution down to zero (watch Bill Gates on TED talking about this), and while there are many worthwhile alternate forms of energy, nuclear power is by far the most cost-effective and clean one. I'm all for it and I hope it continues to grow in the future.