Liquid Thorium Molten Salt Reactor, (long name) - but MSR's (for short) not to be confused with MRI's (Medical Radioactive Imagery) are low cost Nuclear Reactors that produce more energy and are far more safer than Liquid Cooled Nuclear Reactors. While both were in development back in the '50's for whatever reason, LCNR's were the choice of governments and big business to use to produce electricity.
We all love conspiracy theories, well in short, it is like a conspiracy here: The government and big business conspired to bring nuclear energy to the public by way of LCNR's cause they produce far more jobs and would require far more maintenance, hence more jobs, than MSR's. And thus, is the main thrust behind most of governments involvement in bringing new industry or products to market - how many jobs will it produce?
The other end to the argument to use LCNR's over Fossil-Fuels, was that they would be cleaner and cheaper while they produced the energy needed by us to power our homes, businesses, towns and cities, governmental buildings, etc. To this day, (June 25, 2016) they have not proved this and in fact, they have proven to be far more dangerous than any other electrical prodcution process, there is - failure of one plant can kill hundreds if not thousands of people - it can harm wildlife and the environment and totally shut down areas where people and things once lived. The waste it produces, causes even greater risks to man and his environment. It is costly to maintain - thus, the higher cost of electrical generation.
Here comes MSR's to the rescue. While they shouldn't be rescuing anyone or anything - they originally should have been the choice of many to use in developing electrical energy from the gate/start. And why do I say to the rescue? Well, the nuclear waste in this country is a real serious problem - MSR's can use this up - til that fuel is burnt up in it's entirity. Clean disposable waste comes out the other end from MSR use. Next, these plants are far more compact and they can be built relatively anywhere. Especially, in remote areas at a fraction of the cost to build an LCNR. They last longer (they don't need refueled as often) and production runs at a higher percentage than other nuclear means of generating electricity. Thus, less costs and more friendly to the environment and man.
Now, imagine these puppies being reduced in size, small enough to power a plane or a ship, whether cargo, passenger or submarine. Or even a spaceship! Imagine, cities like Detroit or Flint, Michigan coming back from the brink of disaster. Or cities like, Los Angeles, San Francisco, New York or even Washington, D.C. having cheaper cleaner power to rely on, that is basically right there in their backyards. MSR's are a power long overdue and a source of energy to be reckoned with.
I hope I peaked your interests, now you can start looking into it further here: Cheap Energy You Can Stand Behind and even close too.