N-Reactor

An N-Reactor is a type of nuclear reactor designed to produce plutonium-239 for nuclear weapons and, as a secondary purpose, to generate electricity. The "N" designation specifically refers to the New Production Reactor (NPR) program initiated in the United States during the Cold War. The most prominent and only operational example of an N-Reactor was the one located at the Hanford Site in Washington state.

The Hanford N-Reactor was a graphite-moderated, light water-cooled reactor. Unlike typical commercial power reactors that use enriched uranium, the N-Reactor used natural uranium as its fuel. The graphite moderator slowed down neutrons, making them more effective in sustaining the nuclear chain reaction. The light water coolant removed the heat generated by the fission process.

A key feature of the N-Reactor was its ability to be refueled online, meaning that fuel rods could be added and removed while the reactor was operating. This allowed for continuous production of plutonium. The plutonium produced was extracted from the spent fuel through chemical processing at nearby facilities within the Hanford Site.

The N-Reactor operated from 1963 until 1987. Following its shutdown, it was placed in safe storage and is now undergoing a long-term decommissioning process as part of the Hanford Site cleanup. The N-Reactor played a significant role in the United States' nuclear weapons program during the Cold War, but its operation also contributed to environmental contamination at the Hanford Site due to the release of radioactive materials.