Westinghouse AP1000

Westinghouse AP1000
Name	AP1000
Country	United States
Designer	Westinghouse Electric Company
Status	In service / Under construction
Reactor type	Pressurized water reactor
Generation	III+
Thermal power	3400 MWt
Electrical output	1100 MWe (net)
Cooling	Passive safety systems

Contents

Westinghouse AP1000 is a Generation III+ pressurized water reactor designed by Westinghouse Electric Company. The design emphasizes passive safety features derived from experience with Three Mile Island accident, Chernobyl disaster, and lessons incorporated after reviews by agencies such as the Nuclear Regulatory Commission (United States). The AP1000 program has been pursued in multiple countries including China, United Kingdom, and United Arab Emirates with involvement from firms like Toshiba, Bechtel Corporation, and Shanghai Electric Group.

Design and technology

The AP1000 design is a two-loop pressurized water reactor configuration building on precedents set by vendors such as Combustion Engineering and Babcock & Wilcox. Its core design uses fuel assemblies similar to those used at Palo Verde Nuclear Generating Station and leverages steam generator experience from San Onofre Nuclear Generating Station and Vogtle Electric Generating Plant. Key components include a large containment vessel influenced by designs used at Diablo Canyon Power Plant and a compact containment derived from concepts tested at Surry Nuclear Power Plant. The reactor adopts a modular construction approach comparable to methods employed by Shipbuilding Corporation projects and influenced by modular practices at Rolls-Royce Holdings and Korean Electric Power Corporation.

Safety for the AP1000 centers on passive systems utilizing gravity, natural circulation, and stored energy, echoing passive cooling strategies evaluated after Fukushima Daiichi nuclear disaster. The passive core cooling system, passive residual heat removal system, and passive containment cooling system are designed to function without operator action for 72 hours, drawing on regulatory frameworks from International Atomic Energy Agency and testing protocols used by Electric Power Research Institute. The design was reviewed by the Nuclear Regulatory Commission (United States), and aspects were compared with active safety features present at plants like Sequoyah Nuclear Plant and Palo Verde Nuclear Generating Station.

Construction of AP1000 units has proceeded in phases with substantial industry partnerships including China National Nuclear Corporation, State Power Investment Corporation, and Bechtel Corporation. Notable projects include the Sanmen and Haiyang sites in China and the Vogtle units in Georgia (U.S. state), with civil engineering milestones similar to large infrastructure projects such as Three Gorges Dam and Crossrail. Fabrication strategies employed suppliers like Doosan Heavy Industries & Construction and China First Heavy Industries, and modular construction techniques invoked comparisons to programs by Balfour Beatty and Skanska. Delays and schedule changes mirrored issues experienced during builds at Flamanville Nuclear Power Plant and Olkiluoto Nuclear Power Plant.

Commissioning and operation of AP1000 units began with the completion of units at the Sanmen and Haiyang sites in China National Nuclear Corporation-led projects, entering commercial operation following inspections by agencies analogous to State Nuclear Power Technology Corporation. The Vogtle units in Georgia (U.S. state) saw phased commissioning with oversight from the Nuclear Regulatory Commission (United States) and involvement by contractors such as Westinghouse Electric Company and Bechtel Corporation. Start-up testing and power ascension followed established sequences similar to those at Davis-Besse Nuclear Power Station and Oconee Nuclear Station.

Economic assessments for AP1000 projects have involved financiers and regulators including Export-Import Bank of the United States, China Development Bank, and national authorities in United Kingdom and United Arab Emirates. Cost estimates and schedule risk drew comparisons to overruns seen at Flamanville Nuclear Power Plant and Olkiluoto Nuclear Power Plant, influencing policy debates in legislatures such as the United States Congress and parliaments in United Kingdom. Regulatory approval processes navigated frameworks at the Nuclear Regulatory Commission (United States), National Nuclear Safety Administration (China), and Office for Nuclear Regulation (United Kingdom), echoing standards set by the International Atomic Energy Agency.

AP1000 projects experienced controversies over cost overruns, schedule slippage, and supply-chain quality control similar to issues at V.C. Summer Nuclear Station and the Olkiluoto Nuclear Power Plant program. High-profile suppliers and contractors such as Westinghouse Electric Company, Toshiba, and Bechtel Corporation faced scrutiny paralleling inquiries into Areva activities and procurement practices at EDF (Électricité de France). Technical incidents and component inspections prompted regulatory reviews reminiscent of post-incident analyses after Three Mile Island accident and Fukushima Daiichi nuclear disaster, resulting in corrective actions overseen by bodies like the Nuclear Regulatory Commission (United States) and national safety agencies.