So, when do they get their license to build nuclear power plants at sea?

This seems well thought out and prudent:

In a deal with U.S. regulators, BP this summer plans to restart deepwater drilling in the Gulf of Mexico on 10 wells in exchange for tougher safety rules, British media reported Sunday.

I believe for U.S. Oil safety regulators (i.e. people on leave from oil company's) the tougher safety rules involved an increase in nods and winks as the papers were drawn up.