Because they are the first exemplars of these packaged products (note: plural, one each from Framatome|Areva/EDF/Siemens in Europe† and Westinghouse in the US‡)

Because they are the first exemplars of these packaged products (note: plural, one each from Framatome|Areva/EDF/Siemens in Europe† and Westinghouse in the US‡) to be built anywhere in the world ahead of other construction projects. Thus: "double first". † https://en.wikipedia.org/wiki/EPR_(nuclear_reactor) https://en.wikipedia.org/wiki/EPR_(nuclear_reactor) ‡ http://www.westinghousenuclear.com/New-Plants/AP1000-PWR http://www.westinghousenuclear.com/New-Plants/AP1000-PWR ps: it's a little bit worrying I can't find any single commercial page detailing the EPR