DUBAI, July 22 – The Trump administration backs a nuclear energy pact with Riyadh allowing Saudi Arabia to enrich uranium and process spent atomic fuel, two sources have said, a move that may worry regional states concerned about weapons proliferation.Here are some of the main issues at play:WHAT HAS HAPPENED SO FAR?Washington and Riyadh have for years been discussing a nuclear cooperation deal that would give Saudi Arabia access to U.S. technology and American companies a chance to win big contracts for Saudi atomic energy facilities.As always with nuclear technology, worries about security, weapons proliferation and political complications in a tinderbox…