EXPERIMENTAL BREEDER REACTOR-I • A NATIONAL HISTORIC LANDMARK Experimental Breeder Reactor-I EBR-I was designed with two purposes: to generate electricity and – more importantly – to prove the concept of breeding fuel. Breeding fuel means that a reactor creates more nuclear fuel than it consumes – all while making electricity. Light from Nuclear Energy On Dec. 20, 1951, EBR-I became the first nuclear reactor to produce usable amounts of electricity by splitting atoms. EBR-I was the first reactor built at the National Reactor Testing Station (forerunner to today’s Idaho National Laboratory). In 1953, testing at EBR-I confirmed that a reactor could create (or breed) more nuclear fuel than it consumes. This pioneering reactor operated for 12 years before being shut down in December 1963. President Lyndon B. Johnson dedicated EBR-I as a Registered National Historic Landmark in 1966. Nuclear Flight Early in the 1950s, the United States fully believed the Soviet Union had developed nuclear-powered aircraft. At that time, the U.S. did not have the ability to safely refuel long-range bombers in flight and had not developed intercontinental ballistic missiles. Early in the Cold War, a bomber capable of more than a week in the air was considered the first-strike deterrent that was needed. The logical site to build and test those reactor designs was the National Reactor Testing Station. General Electric workers gather for a photo with one of the two nuclear aircraft reactor platforms developed for testing at the National Reactor Testing Station’s Test Area North Hot Shop. 22 28 Mud Lake Rexburg Howe 33 15 93 Idaho National Arco Laboratory 20 26 20 20 Idaho 93 Falls EBR-I Atomic Museum 26 National Historic Craters of Landmark 15 the Moon 91 Blackfoot Open Memorial Day weekend through Labor Day Welcome to the EBR-I Atomic Museum This pamphlet will guide you through EBR-I and give you an idea of how atomic energy Seven days a week • 9 a.m. to 5 p.m. is used to make electricity. Along the tour route, many exhibits help tell the EBR-I story. If you have any questions, ask the tour guide on duty. We hope you’ll enjoy your visit. Free admission Self-Guided Tour Climb the stairs to the first in the form of heat. Two or three neutrons less likely to fission and instead tends to tour stop. from the nucleus of the fissioned U-235 either deflect the neutron or absorb it. atom are released, and they go on to split Nuclear-generated power is When U-238 absorbs a neutron, it 1 other U-235 atoms. That is the fission harnessed in the same way as becomes uranium-239, which quickly chain reaction taking place to generate other sources; heat is created to perform undergoes radioactive decay and turns heat in a nuclear power plant. work. But instead of burning something into plutonium-239. Pu-239 behaves like – coal, oil, wood, biomass – atoms When EBR-I was designed, the goal was the more common reactor fuel U-235 are split, which releases energy in the to build a breeder reactor, which creates (less than 1% of natural uranium), form of heat. Nuclear power plants use more nuclear fuel than it consumes, providing heat and sustaining a fission a sustained chain reaction of splitting so designers needed to engineer a chain reaction. atoms to generate heat, which turns very particular fission environment. Because this reactor actually creates water into steam. The steam spins a That environment makes it more likely Pu-239 fuel, it is known as a breeder. turbine and generator to make electricity. that neutrons will be absorbed by In 1953, EBR-I proved it was creating uranium-238, the more stable form that The atom that easily splits, or fissions, is Pu-239, and by 1963 was creating comprises more than 99% of natural uranium-235. When a U-235 atom is hit by 1.27 atoms for every atom used as fuel. uranium. When hit by a neutron, U-238 is a neutron, it will fission, releasing energy 19-50066 Self-Guided Tour To safely transfer heat from the fission plaque to the right of the signed names. The oil-filled window at the bottom of chain reaction and allow the breeding Take a minute to listen to the voices of the platform stairs, allows you to see to be successful, liquid metal was used people who worked here. The display underneath the reactor. The large round as the coolant in EBR-I. The liquid metal case behind the strand of bulbs shows platform you see on the right side of was a combination of sodium (Na) and one of the original four lightbulbs from the room is the bottom of the elevator potassium (K) and was called “NaK.” 1951. The smaller lightbulb in the case that would raise and lower the breeding A primary coolant loop of NaK flowed was lit in 1963 when EBR-I was the blanket around the core of the reactor. through the reactor and transferred first to generate electricity from an all- You can go inside the breeding-blanket that heat to a second, separate coolant plutonium core. repair room. Operators would work from loop of NaK, which then heated water to Watch your step going downstairs. the outside of this room through the generate steam. glass window. They used manipulator In this room, the heat from the NaK was great for heat transfer, but it 5 arms to open the door at the top of second liquid metal system would ignite and burn when exposed the room and retrieve the breeding converted water into steam, which to air. In contact with water, it would blanket. Because of the high heat inside was then piped upstairs to the turbine/ explode. Great care was taken to keep NaK the reactor, the bricks in the breeding generator, where it produced electricity. isolated, and EBR-I never had any issues. blanket sometimes cracked. Here Although there is no longer any NaK in operators could replace those bricks Go out of the door and turn right the system, this room is locked because and repair the blanket. to the control room. of the asbestos insulation on the pipes. This was the control room where The next stop is around the 2 operators started, controlled corner to the left. and shut down the reactor. Feel free This plaque was installed to push buttons and turn dials. Facing 6 by President Lyndon B. into the room, the left side contains Johnson and Dr. Glenn T. Seaborg, the panels to monitor coolant flow and chairman of the U.S. Atomic Energy temperature. The panels on the right Commission during the dedication look like any standard power plant, and ceremony in 1966 designating EBR-I at the front are the reactor controls. The as a Registered National Historic most interesting button is the SCRAM Landmark. New fuel rods button at the front. A SCRAM is a rapid, were stored in the vault unplanned reactor shutdown. before going into the reactor. The origin of the term SCRAM is printed Before being used, the rods could above the button. be handled safely without shielding. After the fission process occurred in the Also located in the control room is the fuel, the rods became highly radioactive. logbook of Dr. Walter Zinn, the designer You can also see a 5-ton cask that was and director of EBR-I. The book is open to used to safely move the spent fuel rods the first two days that EBR-I generated to a washroom in the basement. The cask electricity. was filled with argon gas to prevent the Continue through the control room to NaK-coated rods from contacting oxygen the top of the reactor. as an additional safety feature. 3 This is the top of the reactor. Continue around the corner Through the plexiglass cover, the to the next stop. “head” of the reactor vessel is visible. This is the end of the When the fuel rods were removed self-guided tour. 7 Beneath that were fuel rods containing from the reactor, some radioactive But there is more to see… U-235. The fuel rods were 10 feet long NaK remained on them. The rods were • Please sign the logbook and tell but contained only 8.5 inches of U-235 lowered into the basement through us about your experience. toward the bottom. The fuel rods were holes in the floor covered by the metal held inside of hexagonal “cans” called plates. The NaK was washed off with • Enjoy the “containment vessel subassemblies. Surrounding the reactor acetone and alcohol. When clean and theater” to learn more about vessel are 15-foot-thick concrete walls to dry, the rods were then stored in the rod Idaho National Laboratory and shield workers from radiation when the farm – evenly spaced storage locations nuclear topics. reactor was operating. Replica fuel rods in concrete with individually numbered • Visit the annex to learn about and subassemblies, including the region holes. The chalkboard was used to keep EBR-II, the continuation of what was of fuel, are displayed. track of the inventory. learned here. EBR-II operated from Also shown in a photo is the breeder Past the rod farm you will see the hot 1964-1994. blanket. It was made of 84 bricks of cell. This was used to visually inspect the • In the parking lot, you’ll find two U-238, each encased in stainless steel used fuel rods. Each window consists reactors built in the 1950s during the cladding, arranged in a cup shape.