Modular construction, using concrete-filled steel boxes, is one of the major features of the Westinghouse AP600 program, which is a small innovative 600 Mwe Advanced Light Water Reactor (ALWR), developed by Westinghouse and a number of subcontractors and associates, amongst which are Bechtel Power Corporation, Avondale Construction Management, MK-Ferguson Company, and ANSALDO from Italy.
The difficulty that the structural design analysis faced is that steel-concrete "sandwich" composite structures are a unique form of construction and none of the existing US codes of practice or design guidelines are directly applicable.
Danay Engineering, contracted to develop an analytical basis for design certification, developed a new analytical methodology for steel-concrete composite panels, currently under publication, which was accepted by the US Nuclear Regulatory Commission.
Danay
Engineering Ltd.