B Reactor facts for kids

B Reactor
U.S. National Register of Historic Places
U.S. National Historic Landmark
The face of B Reactor during construction.
Location in Washington (state)
Location	About 5.3 miles (8.5 km) northeast of junction of State Route 24 and State Route 240 on the Hanford Site
Nearest city	Richland, Washington
Area	9.5 acres (3.8 ha)
Built	June 7, 1943 to September 1944
Architect	E.I. DuPont de Nemours & Company
NRHP reference No.	92000245
Quick facts for kids Significant dates
Added to NRHP	April 3, 1992
Designated NHL	August 19, 2008

The B Reactor is located at the Hanford Site in Richland, Washington. It was the very first large-scale nuclear reactor ever built. This project was a super important part of the Manhattan Project. That was a secret U.S. program during World War II to develop nuclear weapons.

The main goal of the B Reactor was to change natural uranium into something called plutonium-239. This happened through a process called neutron activation. Plutonium was much easier to work with than uranium for making these special weapons. The B Reactor used natural uranium as fuel. It also used graphite to slow down particles and water to keep it cool.

The B Reactor became a U.S. National Historic Landmark in 2008. In 2011, it was suggested to be part of the Manhattan Project National Historical Park. This park remembers the history of the Manhattan Project. You can even take a tour of the reactor if you book in advance!

Building the Reactor

The B Reactor was designed and built by a company called DuPont. Their plans were based on experiments done by Enrico Fermi at the University of Chicago. They also used ideas from the X-10 Graphite Reactor at Oak Ridge National Laboratory. The reactor was meant to run at 250 megawatts (thermal) of power.

The main reason for the reactor was to make plutonium from uranium. Getting pure uranium was very hard and complicated. Making plutonium was much simpler. For example, a uranium plant needed a lot of silver and thousands of workers. The B Reactor needed only a few dozen workers. It also used much less special material.

The biggest part of the reactor was 1,200 tons of graphite. This graphite helped control the nuclear reaction. The reactor didn't need much electricity, just enough to run its cooling pumps.

The reactor building is about 46 by 38 feet and 41 feet tall. The reactor core itself was a large graphite box. It weighed 1,200 tons. It had 2,004 aluminum tubes going through it. These tubes held the uranium fuel.

A thick layer of cast iron surrounded the core. This was a heat shield. Then, other materials like Masonite and steel plates were added. These formed a shield to protect against radiation. The bottom of the shield rested on a thick concrete pad. The graphite helped control the reaction. About 200 tons of uranium slugs were used as fuel. These slugs were small, like a roll of quarters. They were sealed in aluminum cans.

The reactor was cooled by water from the Hanford Reach of the Columbia River. Water was pumped through the aluminum tubes around the uranium slugs. About 75,000 gallons of water were used every minute. This water was then sent to special basins. There, radioactive materials could decay. Any particles would settle out. The water also cooled down before going back into the Columbia River. The river's temperature could not go up by more than 11 degrees Fahrenheit.

Map of the Hanford site with the B/C reactor site shown at the upper left.

How the Reactor Worked

The B Reactor started its first nuclear chain reaction in September 1944. Two other reactors, D and F, started soon after. The B Reactor made plutonium-239 by exposing uranium-238 to neutrons. These neutrons came from the nuclear reaction.

The B, D, and F reactors were built about six miles apart. They were all on the south bank of the Columbia River. Each reactor had its own support buildings. These included a pump house for river water. They also had large storage basins and a water filter plant. Big pumps delivered water to the reactor. There were also systems for emergency cooling if the power went out.

To quickly shut down the reactor, called a scram, safety rods were pushed in fast. As a backup, water with borate was injected into the reactor. Later, a system was added that dropped special steel balls into the reactor.

The plutonium for the first nuclear bomb was made in the B Reactor. This bomb was used in the Trinity test in New Mexico. Plutonium from the B Reactor was also used in the "Fat Man" bomb. This bomb was dropped on Nagasaki, Japan.

The B Reactor ran for twenty years. Other reactors were built later to help. The B Reactor was finally shut down for good in February 1968.

What's Happening Now

Exterior of the Hanford B Reactor as of 2018

Hanford B Reactor Control Station as of 2018

Hanford B Reactor Tubes and Elevator as of 2018

The United States Department of Energy has managed the site since 1977. They offer public tours on certain dates in spring, summer, and fall.

As of 2014, six of the nine reactors at Hanford were in "interim safe storage." This means they were made safe for a while. The B Reactor was special because of its history.

This "safe storage" is also called cocooning or entombment. It involves taking down most of the reactor building. Only the thick concrete shield around the core is left. Any openings are sealed, and a new roof is built. Most other buildings at the first three reactors have also been taken down.

Many other reactors at Hanford have been cocooned. For example, the C reactor was cocooned in 1998. The D reactor was cocooned in 2004. The F reactor was cocooned in 2003. The N-Reactor was finished cocooning in 2012. The Department of Energy checks these cocooned reactors every five years.

The K East and K West reactors were built in the 1950s. They were shut down in the early 1970s. Plans were being made in 2018 to make them safe too.

The B Reactor was added to the National Register of Historic Places in 1992. In 2001, work was approved to make the reactor safe for public tours. It was named a National Historic Landmark in 2008.

In December 2014, the B Reactor became part of the Manhattan Project National Historical Park. This park also includes historic sites in Oak Ridge, Tennessee and Los Alamos, New Mexico. The park officially started in November 2015. The B Reactor might become a museum as part of this park.

Important Dates

See also

In Spanish: Reactor B para niños