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November 23, 2021

Millstone 3, US

By Carmen

Millstone 3 is a 1,280MW nuclear reactor which is located within the premises of Millstone Nuclear Power Plant. It is located in Connecticut, the US. The nuclear reactor is currently generating power and is in active status. The construction on the reactor commenced in Aug, 1974. The first power from the reactor was achieved in Feb, 1986. Subsequent to trial runs the reactor finally entered into commercial operation in Apr, 1986.

PID Project Type Total Capacity (MW) Active Capacity (MW) Pipeline Capacity (MW) Project Status Project Location Project Main Contractor
673 Nuclear 1,280 1,280 Active Connecticut, the US Westinghouse Electric


Millstone 3 is a Generation II nuclear reactor developed by Westinghouse Electric, the main contractor for the project.

The 1,280MW reactor is operated by Dominion Energy Nuclear Connecticut. Dominion Energy, Massachusetts Municipal Wholesale Electric and Green Mountain Power are currently owning the project having ownership stake of 93.5%, 4.8% and 1.7% respectively.

The PWR reactor generates 9,494.66GWh/annum of electricity. It features 580 fuel assemblies in the core of reactor, the place where fission occurs and energy is released. Safety contol rods that are used to control the fission rate in the reactor are 29 in number.

Development Status

The reactor construction commenced in Aug, 1974 and subsequently entered into commercial operation in Apr, 1986.

Contractors Involved

GE Power was selected as the steam turbine supplier for the nuclear reactor. The company provided 1 steam turbine for the project. Westinghouse Electric was selected as an architect engineer for the reactor. The reactor system was supplied by Westinghouse Electric. The reactor vessel has been supplied by Westinghouse Electric. The material used for the construction of the vessel is MnMo SS Clad. The civil works were carried out by Westinghouse Electric.

About Westinghouse Electric

Westinghouse Electric Co LLC (Westinghouse) a subsidiary of Toshiba Corporation, is a nuclear energy company. It offers nuclear plant products, technologies, nuclear fuel, plant design and related services to utilities across the world. The company carries out development, licensing, detailed engineering, project management, component manufacturing and offers startup support for new nuclear plants. It provides a comprehensive range of nuclear fuel and operating plant products and services; and decontamination and decommissioning, and waste management services. The company operates through regional offices in the Americas, Asia, Europe, the Middle East and Africa. Westinghouse is headquartered in Cranberry Township, Pennsylvania, the US.


All power projects included in this report are drawn from GlobalData’s Power Intelligence Center. The information regarding the project parameters is sourced through secondary information sources such as electric utilities, equipment manufacturers, developers, project proponent’s – news, deals and financial reporting, regulatory body, associations, government planning reports and publications. Wherever needed the information is further validated through primary from various stakeholders across the power value chain and professionals from leading players within the power sector.

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