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By Charles Rhodes, P.Eng., Ph.D.

Most presently existing large nuclear power reactors are light water reactors (LWRs), meaning that the core region of the nuclear reactor is cooled with light water. Most of the original first of a kind (FOAK) costs related to development of light water power reactors were originally borne by the US Navy, which today has a large fleet of nuclear powered naval vessels as summarized in the text: Marine Applications of Nuclear Power.

Most light water power reactors are variations on the Westinghouse Pressurized Water Reactor Design. The fuel design for light water cooled reactors is detailed in a document titled Light water reactor fuel design

Light water reactors have the advantage of inherent simplicity. This feature is important from the perspective of personnel training. For marine applications LWRs have the important advantages that they are resistant to damage by water and that the half-life of radio isotopes in the core coolant is relatively short, which allows rapid access for maintenance.

Some of the most modern civilian light water power reactors are in China. Major disadvantages of light water reactors are high operating pressures, production of long lived used fuel waste and poor natural uranium utilization. Generally light water reactors require fuel enrichment (fuel that is enriched in the uranium isotope U-235).

Photo showing 2 AP1000 reactors at the Sanmen nuclear power plant in China.

The state of the art in Light Water Reactors (LWRs) is summarized in the Westinghouse paper: The Design and Safety Features of the IRIS Reactor
and by the Russian VVER Reactor Design

The 9 GWe Tianwan Nuclear Power Plant, a joint Chinese and Russian project:


A novel Light Water Power Reactor is the Russian Reactor Barge

which potentially has major advantages for sale of electricity to emerging countries. If the electricity bills are not promptly paid the barge owners can simply tow the reactor barge away.

New York's Indian Point Nuclear Power Plant



This web page last updated April 30, 2020.

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