In February 2013, the project's construction contractor, Shaw, was purchased by Chicago Bridge & Iron Company (CB&I). On March 12, 2013, construction on Unit 3 officially began with the pour of the basemat concrete for the nuclear island. This operation was completed on March 14. During the weekend of June 1, 2013, assembly of the containment vessel began with the bottom head of the vessel being lifted into place on the nuclear island. By June 2013, the construction schedule had been extended by at least 14 months. On November 21, 2013, the basemat pour for Unit 4 was completed.