Sanmen NPS will be the first implementation of the AP1000pressurized water reactor (PWR) developed by Westinghouse Electric Company. The contract was agreed in July 2007. Announcement of the project start came roughly twelve months after Westinghouse won a bidding contest over other companies. The contract for the new plant involved The Shaw Group (now Chicago Bridge and Iron), a minority shareholder in Westinghouse. Westinghouse is controlled by Japanese giant Toshiba. The Shaw Group will provide engineering, procurement, commissioning, information management and project management services. The first pair of reactors will cost more than 40 billion yuan (US$5.88 billion).
Excavation for the first unit was completed in September 2008. Quality of the pit was certified, putting the project 67 days ahead of schedule. Construction of Sanmen Unit 1 began on April 19, 2009, as the first 5,200 m³ of concrete were poured for the foundation, in a ceremony attended by State Nuclear Power Technology Corporation (SNPTC) chair Wang Binghua and Westinghouse CEO Aris Candris. First concrete for Sanmen 2 was poured on December 15, 2009.