Nuclear fuel market is global with many producers. Fuel price is a tiny fraction of the nuclear electricity cost. Agree to a long-term contract at double today's price and there will be a line of companies running to sign it.
Cameco (and others) put some of their nuclear mining into conservation because there was not enough buyers. Uranium is one of the most abundant elements, the only reason for the shortage of fuel is the politicians reluctance to make nuclear a pillar of the energy production.
Then switch to Niger or Namibia (where France partly gets theirs from), or Canada, or Australia.