6 Nuclear Reactors (Atomic Energy)

6.1 Introduction

During the 1940s, the need for electricity was becoming more and more important as more technologies took advantage of it. Also with the United States looking for a way to end the second World War quickly, we needed a solution. The United States would turn to the power of the atom and on December 2, 1942, the first nuclear reactor was assembled.

“CP-1 (Chicago Pile 1 Reactor)” by Argonne National Laboratory is in the Public Domain, CC0

Enrico Fermi and his team of colleagues built the first nuclear reactor beneath the football stadium of the University of Chicago. Enrico Fermi and some of his colleagues would go on to found the Argonne National Laboratory, a research center working under the U.S. Department of Energy.

Though you may be wondering, what is a nuclear reactor and how does it work? Those are things that will be discussed in this chapter as well as what its impact on the American people, the evolution of nuclear energy, and its influence on other technologies and fields of study.

6.2 What is a Nuclear Reactor?

A nuclear reactor is a type of energy generator that takes advantage of nuclear fission. Nuclear fission is a physical process of controlling nuclear chain reactions to produce heat. When fission occurs, atoms split and release energy in the form of heat. An atom is a basic chemical unit of an element. Atoms are composed of subatomic particles called neutrons, electrons and protons. When the atom is split, the neutrons are released and slam into other atoms. This causes them to split as well forming a chain reaction. The chain reaction needs to be stabilized to prevent disaster .

A modern nuclear reactor uses Uranium that has been processed into ceramic pellets as a fuel source. Then these pellets are placed into metal tubes and sealed to create a fuel rod. These fuel rods are bundled together creating a fuel assembly and then immersed in water. The water acts as a coolant for the rods as well as a moderator. A moderator is a term for a substance that helps slow down neutrons generated by nuclear fission to help sustain the nuclear reaction.

Control rods can be inserted into the reactor core to decrease the rate of reaction, or removed from the core to increase the rate of reaction. Like mentioned previously, the process of nuclear fission generates heat and while these fuel assemblies are submerged in water, they heat the water up and generate steam. The steam is then used to spin a turbine which then generates electricity. Below is a diagram depicting a pressurized-water reactor, the most common type of nuclear reactor in the United States.

With the creation of nuclear reactors also came the creation of other technologies such as geiger counters and lead-lined suits. Geiger counters were created to be able read radiation levels in the area it is used in and the suits were designed to stop or limit the radiation exposure to the user.

Under stable conditions, a nuclear reactor can produce large amounts of carbon free energy, but if run without care, it could lead to serious consequences.

6.3 The Creation of Nuclear Energy

6.3.1 Why Was the Nuclear Reactor Created?

The nuclear reactor did not initially have positive intentions. The team that Enrico Fermi was helping to develop the nuclear reactor with was originally the Manhattan Project’s Metallurgical Laboratory. They were helping develop the science behind the constructing of the first atom bomb. The reactor was developed as a way to demonstrate how to maintain nuclear fission stably while energy production was an afterthought.

The group named their lab the Argonne National Laboratory,  because in 1943, the first nuclear reactor was disassembled and moved into the “Argonne Forest” section in Palos Park as part of Cook County Forest Preserve. Presently that section of forest has been renamed but its name lives on in the Argonne National Laboratory. While building the reactor was important, the researchers also wanted to educate others effectively to support the next generation of nuclear workers.

6.3.2 Atomic Fields of Study

With the creation of the nuclear reactor came great challenges. The process of nuclear fission needs to be kept stable as too little reaction could cause the nuclear reactor to shutdown and too much reaction could cause the reactor to go into meltdown. A meltdown occurs when the reactor goes supercritical and performs chain reactions controllably. This happened at the Chernobyl Atomic Energy Station in Ukraine on April 25th, 1986. One of the reactors went supercritical, and exploded damaging the immediate area and releasing dangerous levels of radiation to itself and neighboring countries.

With an event like this always being a possibility,  educating the populace about the risks and mitigation strategies associated with atomic energy was important. With the creation of the first nuclear reactor came the creation of new fields of study associated with it. People needed to be able to teach this information to others and having a professionally certified individual teach his knowledge to others would help greatly to aid humanity. Several new fields of study were created such as nuclear engineering and nuclear physics.

Another thing to consider was how to teach this information to aspiring nuclear professionals. In the 1950s, American universities began using a new “swimming pool” reactor which was specifically designed to be able to easily show the inner workings of a nuclear reactor. They were also named “teaching reactors,” these reactors were developed specifically for pedagogical or educational purposes.

With the development of nuclear energy, people had their own opinions on it. Nuclear energy itself had a direct impact on American society from when it was first invented to today.

6.4 Impacts of Nuclear Energy

6.4.1 Negative Impacts

The nuclear reactor was first created as a proof of concept for the Manhattan Project. By the Cold War, any technology nuclear related was built to help fight the spread of Communism, either directly or indirectly. In 1947, the Soviet Union detonated their first atomic bomb, sparking a nuclear arms race that would last decades. Although developments were made in energy production, their primary purpose was to demonstrate superiority over political adversaries. The Chernobyl incident led people to believe that nuclear energy was too dangerous to be handled. Another event, The Three-Mile Island incident, took place in Pennsylvania and created another scare where the reactor had a partial meltdown but was stopped before it could fully meltdown. It was not as dangerous as initially thought, but those who lived near Three-Mile Island were worried that they may have to abandon their homes.

6.4.2 Positive Impacts

Though the creation of the nuclear reactor might have been for war it did have some positive effects such as a new alternative source of renewable energy that was also carbon free. Nuclear energy would also be used to power submarines as well as homes and businesses. This is a promising sign that the reactors may be implemented into other technologies.

As knowledge of nuclear energy improved, so did safety measures. Fail safes have been implemented and protocols have been assigned to lower the chance of catastrophe .Something else to consider is that several variations of nuclear reactors have been created. These reactors have different power outputs, requirements and utilizations.

6.5 Evolution of Nuclear Reactors and Their Use Today

After World War II, America sought to improve upon the initial reactor design to make it more productive, safer to handle and easier to manufacture and produce.

“Boiling Water Reactor (BWR)” by U.S. Department of Energy is in the Public Domain

As time has passed, different reactors were invented that were created with a specific purpose in mind. The previously mentioned “swimming pool” reactor was created specifically designed with the intention of being fully viewable from above. All the inner workings of the reactor could be viewed easily from onlookers from up-above. These reactors were first used inside universities to teach students how the reactors functioned.

In the United States currently, all commercial nuclear reactors are a type of reactor called a light-water reactor. A light-water reactor is a reactor that uses water as both a coolant and moderator. Out of these reactors, over 65% are the Pressurized Water Reactor mentioned in Figure 1.2 and roughly a third are a Boiling Water Reactor(BWR) shown in Figure 1.3.

The only difference between a BWR and FWR is that within a FWR, water is not allowed to come to a boil as it is moved too quickly for heat to build up. Other than the PWR having its own designated pressure tank and steam area, these reactors are roughly the same as they both recycle the water they use to keep the reactors cool and take advantage of the same formula to maintain nuclear fission.

Chapter Summary:

Nuclear energy is an integral part of the development of the United States today as it helped lead America to becoming a global power. Nuclear energy, though originally created for war, has benefited those who want to use it as a clean renewable energy source. Nuclear reactors have gone under several revisions to make them safer and give them new purpose. The future may hold greater potential for the development of nuclear energy as it becomes cheaper to produce and more widely available.

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