Why Did We Give up on Molton Salt Reactors?

 News is that China will open operation of the first thorium molton salt reactor this month, bringing indignant cries from some in the U.S. as to why the U.S. cannot do this.

  Actually -- though perhaps ours wasn't a thorium MSR -- we once were the world leader in the world developing molten salt reactors. But we gave it up. Only twice had MSRs ever operated and both times it had been in the United States. But, look how long ago that was -- one was in the 1950s and the other in the 1960s. 

  Why did we give them up? Safety concerns? MSRs are safer than other nuclear reactors because they operate with a fuel that comes already in a molton state and if there is an emergency, the fuel mixture drains to a containment holder where it solidifies.