Last updated: April 5, 2023
Lesson Plan
Science of the B Reactor at Hanford, Washington
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- Grade Level:
- Upper Elementary: Third Grade through Fifth Grade
- Subject:
- Science,Social Studies
- Lesson Duration:
- 90 Minutes
- Common Core Standards:
- 3.RI.7, 4.RI.7, 3.RL.4, 4.RL.4, 5.RL.4, 3.SL.3, 4.SL.1.d, 4.SL.2, 4.SL.3, 5.SL.1.d, 5.SL.2, 5.SL.3
- Thinking Skills:
- Remembering: Recalling or recognizing information ideas, and principles. Understanding: Understand the main idea of material heard, viewed, or read. Interpret or summarize the ideas in own words. Applying: Apply an abstract idea in a concrete situation to solve a problem or relate it to a prior experience. Analyzing: Break down a concept or idea into parts and show the relationships among the parts. Creating: Bring together parts (elements, compounds) of knowledge to form a whole and build relationships for NEW situations.
Essential Question
What is the basic nuclear structure and changes that happen during transmutation and fission?
Objective
To understand the basic nuclear structure and changes that happen during transmutation and fission.
Background
The Manhattan Project, America’s wartime effort to build an atomic bomb, was so promising, yet so unlikely to succeed, that two independent paths were followed, in the hopes that at least one of them would produce a war-changing bomb.
One of those methods was based on using carefully refined uranium as the heart of the bomb. That work was done at Oak Ridge, Tennessee. The second method was based on the recently discovered element, plutonium. But unlike uranium, plutonium was almost nonexistent in nature, but could be manufactured. And that job would be done at the Hanford Engineer Works (the Hanford site), in the desert of southeastern Washington state.
The manufacturing process at Hanford was developed from what Enrico Fermi and his team proved when they constructed the world’s first, albeit small-scale, nuclear reactor in Chicago in 1942. If a reactor could be built sufficiently large, the intense flow of neutrons within it could, almost magically, change uranium into plutonium. This process of transmutation would not be creating gold from straw or lead, but would be creating something much more valuable.
To that end, the Army Corps of Engineers took over more than 500 square miles of land, including the towns of Hanford, White Bluffs, and Richland, in Washington state. The vast, remote site was bordered by the Columbia River, a critical resource for cooling in the manufacturing process, with vast amounts of cool and relatively pure water. The process at Hanford involved three steps.
First, many tons of uranium would be formed into 8.7-inch rods, about an inch and a half in diameter. Each was then clad in aluminum, like being canned. The result was commonly referred to as a fuel slug, tens of thousands of which would be needed for the next step of the process.
Three nuclear reactors were built at Hanford, each basically a copy of the others. The brand-new and unproven technology was so uncertain that building three would increase the odds of at least one succeeding. At the core of each reactor was a huge matrix of graphite blocks, measuring 36 feet by 36 feet by 28 feet front to back, and enclosed in five feet of heavy shielding. From front to back ran 2004, 1.7-inch aluminum tubes, into which were loaded more than 60,000 uranium fuel slugs. All-important cooling water would flow in the narrow space between the slugs and the aluminum tube. It was Hanford’s B Reactor that was the first reactor to be built and then loaded with fuel slugs. When the operators withdrew the control rods, the nuclear chain reaction began, and the world’s first full-scale nuclear reactor went into service on September 26, 1944.
In the midst of the intense nuclear chain reaction in the reactors, some neutrons would merge with uranium atoms, which would eventually produce atoms of plutonium—the transmutation process.
After a sufficient time in the operating reactor, fuel slugs would be pushed out the back of the reactor into a deep pool of water, which would cool them while also protecting the workers from the intense radiation they produced. After a period of time, the fuel slugs would be transported in heavily shielded railroad cars across the Hanford site, for the third step in the manufacturing process.
This was the chemical-processing plant, where the highly radioactive reactor fuel would be treated in batches of about 3000 kg. The fuel would be dissolved in acid and then put through a series of chemical processes that eventually extracted a small amount of plutonium—a very small amount. In 3000 kg of uranium, perhaps three-quarters of a kilogram (750 grams) of plutonium would be produced (0.025 percent). So, what happened to the rest of each batch?
In the early days at Hanford, everything that wasn’t plutonium would be dumped into underground storage tanks, to be dealt with only when the urgency of the war ended (and is still being dealt with today). Along with the original uranium and aluminum cladding, there were by-products of the nuclear fission process, many of which were quite radioactive. There were also the chemicals that had been used in the various steps of the process. All in all, the mix of metals, chemicals, and radioactivity in the waste at Hanford created a serious and very expensive clean-up process, still being dealt with 75 years later.
Finally, when a sufficient amount of plutonium had been produced, it was carefully and secretly shipped to the Manhattan Project site at Los Alamos, New Mexico. There, scientists, engineers, and craft workers designed and built the world’s first atomic bomb from Hanford plutonium, which was successfully detonated in the Trinity test, in New Mexico, on July 16, 1945. A few weeks later, on August 6, the Little Boy bomb, as it was called, which was built from Oak Ridge uranium, was detonated over the Japanese city of Hiroshima. And then, on August 9, 1945, Hanford plutonium exploded in the Fat Man bomb over the city of Nagasaki, Japan. This was the second bomb used on human populations and, so far, the last.
Bibliography
Rhodes, Richard. The Making of the Atomic Bomb. New York: Simon & Schuster, 1986.
Smyth, Henry De Wolf. Atomic Energy for Military Purposes, 1945. California: Stanford University Press, 1989
Preparation
Prepare supplies:
- Create notecards with new nomenclature written on each: atom, electron, proton, neutron, fission, chain reaction, transmutation
- Create small green circles with E on one side and – on other
- Create larger purple circles with P on one side and + on other
- Create yellow circles with N on one side, same size as P
- Print and assemble mini-book for each student
- With the printed side face up, fold in half one way, then the other (hot dog and hamburger folds). Unfold.
- With paper in landscape, fold shorter edges into the center.
- Fold paper in half along center fold so that if you look at it level it looks like a W. Cut along the solid line.
- Holding the two folds at the peak of the W, twist them so the other pages go together, then fold with the cover on top.
- Use thumb nail or edge of scissors to crease all folds.
- Have purple, yellow, and green crayons/colored pencils
- Print picture of uranium ore
- Print picture of plutonium buttons
Materials
Sample script for the Science of the B Reactor lesson.
Science of the B Reactor mini-book for the students.
Picture of uranium ore.
Picture of plutonium buttons.
Lesson Hook/Preview
Watch the Hanford Made video (15 minutes).
Procedure
- Prepare supplies and digital technology.
- Provide each student with a Science of the B Reactor Mini-Book.
- Introduce and explain lesson.
- Play Hanford Made video.
- Facilitate lesson.
Vocabulary
- Atom - the smallest thing you can break matter into that still has its properties
- Electron - particle of an atom which has a negative charge and is outside the nucleus
- Proton - particle of an atom which has a positive charge and is inside the nucleus
- Neutron - particle of an atom which has a neutral charge and is inside the nucleus
- Transmutation - changing an element into another element
- Fission - splitting the nucleus of an atom
- Chain reaction - when free neutrons from fission run into more atoms and cause more fission
Enrichment Activities
Atom Tag
- This game is called Atom Tag. Atoms are organized by the number of protons in their nucleus, that give them their atomic number.
- Everyone will run around a playing space. When the facilitator yells out “Atom number ___” everyone will be protons trying to get into a nucleus group with that number.
- If someone does not make it into an atom with the right number of protons, then they join the facilitator for a round to help choose the atom number. They can jump back in the next time.