The B Reactor 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 ...

, near

Richland, Washington Richland () is a city in Benton County, Washington, United States. It is located in southeastern Washington at the confluence of the Yakima and the Columbia Rivers. As of the 2020 census, the city's population was 60,560. Along with the nearby c ...

, was the first large-scale

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 fr ...

ever built. The project was a key part of the

Manhattan Project The Manhattan Project was a research and development undertaking during World War II that produced the first nuclear weapons. It was led by the United States with the support of the United Kingdom and Canada. From 1942 to 1946, the project w ...

, the United States nuclear weapons development program during

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing ...

. Its purpose was to convert natural (not isotopically enriched) uranium metal into

plutonium-239 Plutonium-239 (239Pu or Pu-239) is an isotope of plutonium. Plutonium-239 is the primary fissile isotope used for the production of nuclear weapons, although uranium-235 is also used for that purpose. Plutonium-239 is also one of the three mai ...

neutron activation Neutron activation is the process in which neutron radiation induces radioactivity in materials, and occurs when atomic nuclei capture free neutrons, becoming heavier and entering excited states. The excited nucleus decays immediately by emit ...

, as plutonium is simpler to chemically separate from spent fuel assemblies, for use in nuclear weapons, than it is to isotopically enrich uranium into weapon-grade material. The B reactor was fueled with metallic natural uranium, graphite moderated, and water-cooled. It has been designated a U.S.

National Historic Landmark A National Historic Landmark (NHL) is a building, district, object, site, or structure that is officially recognized by the United States government for its outstanding historical significance. Only some 2,500 (~3%) of over 90,000 places listed ...

since August 19, 2008 and in July 2011 the National Park Service recommended that the B Reactor be included in the

Manhattan Project National Historical Park Manhattan Project National Historical Park is a United States National Historical Park commemorating the Manhattan Project that is run jointly by the National Park Service and Department of Energy. The park consists of three units: one in Oak Ri ...

commemorating the Manhattan Project. Visitors can take a tour of the reactor by advance reservation.

Reactor design and construction

The reactor was designed and built by E. I. du Pont de Nemours and Company based on experimental designs tested by Enrico Fermi at the

University of Chicago The University of Chicago (UChicago, Chicago, U of C, or UChi) is a private university, private research university in Chicago, Illinois. Its main campus is located in Chicago's Hyde Park, Chicago, Hyde Park neighborhood. The University of Chic ...

, and tests from the X-10 Graphite Reactor at

Oak Ridge National Laboratory Oak Ridge National Laboratory (ORNL) is a U.S. multiprogram science and technology national laboratory sponsored by the U.S. Department of Energy (DOE) and administered, managed, and operated by UT–Battelle as a federally funded research an ...

. It was designed to operate at 250 megawatts (thermal). The purpose of the reactor was to breed plutonium from natural (not isotopically enriched) uranium metal, as uranium enrichment was a difficult process, while plutonium is relatively simple to process chemically. The Y12 uranium enrichment plant required 14,700 tons of silver for its enrichment

calutron A calutron is a mass spectrometer originally designed and used for separating the isotopes of uranium. It was developed by Ernest Lawrence during the Manhattan Project and was based on his earlier invention, the cyclotron. Its name was derive ...

s, as well as 22,000 employees and more electrical power than most entire states required at the time. Reactor B required only a few dozen employees and fewer exotic materials, which were also required in far smaller amounts. The largest part of the reactor was 1200 tons of graphite used as a moderator, and its power consumption was vastly smaller, requiring only enough electricity to run the cooling pumps. The reactor occupies a footprint of (about and is tall, occupying a volume of . The

reactor core A nuclear reactor core is the portion of a nuclear reactor containing the nuclear fuel components where the nuclear reactions take place and the heat is generated. Typically, the fuel will be low-enriched uranium contained in thousands of indiv ...

itself consisted of a graphite box measuring occupying a volume of and weighing . It was penetrated horizontally through its entire length by 2,004 aluminum tubes and vertically by channels for the vertical safety rods. The core is surrounded by a thermal shield of

cast iron Cast iron is a class of iron– carbon alloys with a carbon content more than 2%. Its usefulness derives from its relatively low melting temperature. The alloy constituents affect its color when fractured: white cast iron has carbide impur ...

thick weighing .

Masonite Masonite is a type of hardboard, a kind of engineered wood, which is made of steam-cooked and pressure-molded wood fibers in a process patented by William H. Mason. It is also called Quartrboard, Isorel, hernit, karlit, torex, treetex, and ...

and steel plates enclose the thermal shield on its top and sides, forming a biological shield for

radiation protection Radiation protection, also known as radiological protection, is defined by the International Atomic Energy Agency (IAEA) as "The protection of people from harmful effects of exposure to ionizing radiation, and the means for achieving this". Expos ...

. The bottom of the thermal shield is supported by a concrete pad topped by cast-iron blocks. The

graphite Graphite () is a crystalline form of the element carbon. It consists of stacked layers of graphene. Graphite occurs naturally and is the most stable form of carbon under standard conditions. Synthetic and natural graphite are consumed on lar ...

composition was selected to

moderate Moderate is an ideological category which designates a rejection of radical or extreme views, especially in regard to politics and religion. A moderate is considered someone occupying any mainstream position avoiding extreme views. In American ...

the

nuclear reaction In nuclear physics and nuclear chemistry, a nuclear reaction is a process in which two nuclei, or a nucleus and an external subatomic particle, collide to produce one or more new nuclides. Thus, a nuclear reaction must cause a transformatio ...

fueled by of

uranium Uranium is a chemical element with the symbol U and atomic number 92. It is a silvery-grey metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. Uranium is weak ...

slugs approximately diameter long (the approximate size of a roll of quarters), sealed in aluminum cans, and loaded into the aluminum tubes. The reactor was

water-cooled Cooling tower and water discharge of a nuclear power plant Water cooling is a method of heat removal from components and industrial equipment. Evaporative cooling using water is often more efficient than air cooling. Water is inexpensive and no ...

, with cooling water pumped from the

Hanford Reach The Hanford Reach is a free-flowing section of the Columbia River, around long, in eastern Washington state. It is named after a large northward bend in the river's otherwise southbound course. Hanford Reach is the only section of the Columbia i ...

of the Columbia River through the aluminum tubes around the uranium slugs at the rate of per minute. The water was discharged into

settling basin A settling basin, settling pond or decant pond is an earthen or concrete structure using sedimentation to remove settleable matter and turbidity from wastewater. The basins are used to control water pollution in diverse industries such as agricul ...

s, then returned to the river after allowing time for the decay of radioactive materials, the settling out of particulate matter, and for the water to cool so it could be returned to the Columbia River. Water returning to the river was prohibited from raising the temperature of the river by more than 11 °F. Hanford Reach National Monument

Reactor operation

The B Reactor had its first nuclear chain reaction in September 1944, the D Reactor in December 1944 and the F Reactor in February 1945. The initial operation was halted by a problem identified as neutron absorption by the fission product Xe-135, first identified in a research paper of Chien-Shiung Wu that was shared with Fermi. It was overcome by increasing the amount of uranium charged. The reactor produced

by irradiating uranium-238 with

neutron The neutron is a subatomic particle, symbol or , which has a neutral (not positive or negative) charge, and a mass slightly greater than that of a proton. Protons and neutrons constitute the nuclei of atoms. Since protons and neutrons beh ...

s generated by the nuclear reaction. It was one of three reactors – along with the D and F reactors – built about six miles (10 km) apart on the south bank of the Columbia River. Each reactor had its own auxiliary facilities that included a river pump house, large storage and settling basins, a filtration plant, large motor-driven pumps for delivering water to the face of the pile, and facilities for emergency cooling in case of a power failure. Emergency shutdown of the reactor, referred to as a

SCRAM A scram or SCRAM is an emergency shutdown of a nuclear reactor effected by immediately terminating the fission reaction. It is also the name that is given to the manually operated kill switch that initiates the shutdown. In commercial reactor ...

, was attained either by rapidly fully inserting the vertical safety rods or, as a backup method, by the injection of

borate A borate is any of several boron oxyanions, negative ions consisting of boron and oxygen, such as orthoborate , metaborate , or tetraborate ; or any salt with such anions, such as sodium metaborate, and disodium tetraborate . The name also re ...

d water into the reactor. In January 1952, the borated water system was replaced by a "Ball-3X" system that injected

nickel Nickel is a chemical element with symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel is a hard and ductile transition metal. Pure nickel is chemically reactive but large pieces are slow ...

-plated high- boron steel balls into the channels occupied by the vertical safety rods. The plutonium for the nuclear bomb used in the

Trinity test Trinity was the code name of the first detonation of a nuclear weapon. It was conducted by the United States Army at 5:29 a.m. on July 16, 1945, as part of the Manhattan Project. The test was conducted in the Jornada del Muerto desert abo ...

New Mexico ) , population_demonym = New Mexican ( es, Neomexicano, Neomejicano, Nuevo Mexicano) , seat = Santa Fe , LargestCity = Albuquerque , LargestMetro = Tiguex , OfficialLang = None , Languages = English, Spanish ( New Mexican), Navajo, Ke ...

and the

Fat Man "Fat Man" (also known as Mark III) is the codename for the type of nuclear bomb the United States detonated over the Japanese city of Nagasaki on 9 August 1945. It was the second of the only two nuclear weapons ever used in warfare, the fir ...

bomb dropped on Nagasaki, Japan was created in the B reactor. The B Reactor ran for two decades, and was joined by additional reactors constructed later. It was permanently shut down in February 1968.

Current status

The

United States Department of Energy The United States Department of Energy (DOE) is an executive department of the U.S. federal government that oversees U.S. national energy policy and manages the research and development of nuclear power and nuclear weapons in the United Stat ...

has administered the site since 1977 and offers public tours on set dates during the spring, summer, and fall of the year, as well as special tours for visiting officials. six of the nine production reactors at Hanford were considered to be in "interim safe storage" status, and two more were to receive similar treatment. The exception was the B Reactor, which was given special status for its historical significance. In a process called cocooning or entombment, the reactor buildings are demolished up to the

concrete Concrete is a composite material composed of fine and coarse aggregate bonded together with a fluid cement (cement paste) that hardens (cures) over time. Concrete is the second-most-used substance in the world after water, and is the most wid ...

shield around the

. Any openings are sealed and a new roof is built. Most auxiliary buildings at the first three reactors have been demolished, as well. The C reactor was put into operation in 1952 and was shut down in 1969. It was cocooned as of 1998. The D reactor operated from 1944 to June 1967, and was cocooned in 2004. The DR Reactor went online in October 1950, and was shut down in 1964. It was cocooned in 2002. The F reactor was shut down in June 1965 and cocooned in 2003. The H Reactor became operational as of October 1949 and was shut down as of April 1965. It was cocooned as of 2005. Cocooning of the N-Reactor, which operated from 1963 to 1987, was completed as of June 14, 2012. The decommissioned reactors are inspected every five years by the Department of Energy. The K East and K West reactors were built in the 1950s and went into use in 1955. They were shut down in 1970 and 1971, but reused temporarily for storage later. Preliminary plans for interim stabilizing of the K-East and K-West reactors were underway as of January 30, 2018. The B Reactor was added to the

National Register of Historic Places The National Register of Historic Places (NRHP) is the United States federal government's official list of districts, sites, buildings, structures and objects deemed worthy of preservation for their historical significance or "great artistic ...

(#) on April 3, 1992. A Record of Decision (ROD) was issued in 1999, and an EPA Action Memorandum in 2001 authorized hazards mitigation in the reactor with the intention of allowing public tours of the reactor. It was named a

on August 19, 2008. In December 2014, passage of the 2015

National Defense Authorization Act The National Defense Authorization Act (NDAA) is the name for each of a series of United States federal laws specifying the annual budget and expenditures of the U.S. Department of Defense. The first NDAA was passed in 1961. The U.S. Congress o ...

(NDAA) made the B reactor part of the

, which also includes historic sites at Oak Ridge, Tennessee and

Los Alamos, New Mexico Los Alamos is an census-designated place in Los Alamos County, New Mexico, United States, that is recognized as the development and creation place of the atomic bomb—the primary objective of the Manhattan Project by Los Alamos National Labo ...

. The park was formally established by a Memorandum of Agreement on November 10, 2015, which was signed by the

National Park Service The National Park Service (NPS) is an agency of the United States federal government within the U.S. Department of the Interior that manages all national parks, most national monuments, and other natural, historical, and recreational propert ...

and the

Department of Energy A Ministry of Energy or Department of Energy is a government department in some countries that typically oversees the production of fuel and electricity; in the United States, however, it manages nuclear weapons development and conducts energy-re ...

. Museum development at Hanford may include the B Reactor, Bruggemann's Warehouse, Hanford High School, Pump House, and White Bluffs Bank.

Timeline of major events

References

External links

*
"Ranger in Your Pocket" online tours
Atomic Heritage Foundation
Hanford 25th Anniversary Celebration
Video of the 25th anniversary celebration of the construction of B Reactor
B Reactor Museum Association
A collection of Hanford-related documents from a group working to preserve the B-100 Reactor at Hanford.
Hanford Site Tours
– Department of Energy, includes B Reactor {{Authority control Hanford Site Historic American Engineering Record in Washington (state) Former nuclear research institutes Manhattan Project sites Defunct nuclear reactors Graphite moderated reactors Military nuclear reactors Nuclear reactors in Washington (state) Buildings and structures in Benton County, Washington Cold War museums in the United States Museums in Benton County, Washington History of physics Nuclear history of the United States Nuclear weapons infrastructure of the United States Infrastructure completed in 1944 Energy infrastructure on the National Register of Historic Places Historic Civil Engineering Landmarks Industrial buildings and structures on the National Register of Historic Places in Washington (state) Military facilities on the National Register of Historic Places in Washington (state) National Historic Landmarks in Washington (state) National Register of Historic Places in Benton County, Washington World War II on the National Register of Historic Places 1944 establishments in Washington (state)