The N-Reactor was a water/graphite-

moderated Moderation is the process of eliminating or lessening extremes. It is used to ensure normality throughout the medium on which it is being conducted. Common uses of moderation include: *Ensuring consistency and accuracy in the marking of stud ...

nuclear reactor A nuclear reactor is a device used to initiate and control a fission nuclear chain reaction or nuclear fusion reactions. Nuclear reactors are used at nuclear power plants for electricity generation and in nuclear marine propulsion. Heat from nu ...

constructed during the

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and operated by the

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government at the

Hanford Site The Hanford Site is a decommissioned nuclear production complex operated by the United States federal government on the Columbia River in Benton County in the U.S. state of Washington. The site has been known by many names, including SiteW a ...

Washington Washington commonly refers to: * Washington (state), United States * Washington, D.C., the capital of the United States ** A metonym for the federal government of the United States ** Washington metropolitan area, the metropolitan area centered on ...

; it began production in 1963. It was a one-of-a-kind design in the U.S., being both a

plutonium Plutonium is a radioactive chemical element with the symbol Pu and atomic number 94. It is an actinide metal of silvery-gray appearance that tarnishes when exposed to air, and forms a dull coating when oxidized. The element normally exhibi ...

production reactor for

nuclear weapon A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission (fission bomb) or a combination of fission and fusion reactions ( thermonuclear bomb), producing a nuclear explosion. Both bom ...

s and, from 1966, producing steam to allow production of electricity to feed the civilian

power grid An electrical grid is an interconnected network for electricity delivery from producers to consumers. Electrical grids vary in size and can cover whole countries or continents. It consists of:Kaplan, S. M. (2009). Smart Grid. Electrical Power ...

via the

Washington Public Power Supply System Energy Northwest (formerly Washington Public Power Supply System) is a public power joint operating agency in the northwest United States, formed in 1957 by Washington state law to produce at-cost power for Northwest utilities. Headquartered in ...

or WPPSS. The power rating of the N-Reactor was 4000 MWt, with a power output of 800 MWe at the power generating plant. In an improvement on the earlier Hanford reactors, N-Reactor was built with a confinement building (although not a

containment building A containment building is a reinforced steel, concrete or lead structure enclosing a nuclear reactor. It is designed, in any emergency, to contain the escape of radioactive steam or gas to a maximum pressure in the range of . The containment i ...

). In the event of an accidental release of steam, air and steam would vent through filters that confined any radioactive particles present. It was partially moderated with graphite, but had a negative void coefficient due to also using moderation from the coolant water, meaning it was thermally stable. The reactor was shut down in 1987, when the Secretary of Energy determined that no more plutonium was needed and placed on

cold standby Cold is the presence of low temperature, especially in the atmosphere. In common usage, cold is often a subjective perception. A lower bound to temperature is absolute zero, defined as 0.00K on the Kelvin scale, an absolute thermodynamic ...

in 1988, with "final deactivation" beginning in 1994 and completing in 1998. Deactivation consisted of shutdown and isolation of operational systems and the cleanup of radiological and hazardous waste. N-Reactor (the 105-N Reactor and the 109-N Heat Exchanger Building) were placed in Interim Safe Storage (ISS) in 2012. ISS consists of the removal of the fuel storage basin, ancillary support facilities, and most portions of the shield wall that surround the 105-N Reactor. In addition, the 109-N Heat Exchanger Building was removed up to the steam generator cells. A new steel roof was installed over the remaining structures. Before and after pictures are found in the facility status change form. Final room status report of the current as-left condition of accessible rooms in the ISS has been documented.

References

External links

Department of Energy virtual tour

Photo of site

Chernobyl lessons learned review of N Reactor, 1987. DOI: 10.2172/719193

Article about Hanford One and the N-Reactor
Graphite moderated reactors Nuclear power plants in Washington (state) Hanford Site {{nuclear-energy-stub

See also

References

External links