Nuclear Fission

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Nuclear Fission

This lesson aligns with NGSS PS1.C

Introduction

Nuclear fission is a transformative process characterized by the splitting of a large atomic nucleus upon collision with a free neutron. The kinetic energy carried by the neutron imparts a force upon the large nucleus, inducing deformation and ultimately leading to its division into smaller nuclei, each belonging to different elements. Alongside this elemental transformation, the fission process also releases gamma rays and additional free neutrons. In this article, we will learn about what nuclear fission is, how it works as well as its application in various fields.

Historical Milestones: Otto Hahn and Fritz Strassmann

The exploration of nuclear fission began with the groundbreaking work of German chemists Otto Hahn and Fritz Strassmann in 1938. They made the pivotal discovery that bombarding uranium with neutrons resulted in the formation of lighter elements, contrary to the expectation of a heavier product. This unexpected outcome laid the foundation for the recognition of nuclear fission as a distinct and powerful process.

Otto Hahn and Fritz Strassmann's work eventually led to the understanding that the uranium nucleus was undergoing a process of splitting into smaller fragments. The subsequent theoretical explanation by Lise Meitner and Otto Frisch elucidated the mechanics of this extraordinary phenomenon. This groundbreaking research opened the door to both peaceful and destructive applications of nuclear fission.

What is Nuclear Fission?

Nuclear fission is a phenomenon characterized by the splitting of an atom's nucleus, resulting in the formation of two smaller nuclei, free neutrons, and a substantial release of energy. The nuclear fission of Uranium-235 serves as a noteworthy example, producing isotopes such as barium-144 and krypton-89, among others.

Nuclear reaction for U-235:

This equation represents the nuclear fission reaction of Uranium-235, wherein the uranium-235 nucleus absorbs a neutron, leading to the formation of barium-141 and krypton-92 isotopes. Additionally, three neutrons are released during the process, accompanied by a significant release of energy. This exemplifies a fundamental instance of nuclear fission, showcasing the transformation of a heavy atomic nucleus into smaller fragments, release of neutrons, and the liberation of energy.

Nuclear Reaction for U-233:

Another example of nuclear fission is the splitting of Uranium-233. The equation of the reaction has been mentioned below:

It is crucial to note that the specific isotopes generated can vary depending on the initial elements involved in the fission reaction.

The initiation of nuclear fission is typically induced by bombarding a heavy atomic nucleus with neutrons. This collision causes the absorption of the neutron's energy into the nucleus, prompting it to split into two smaller nuclei. The outcome is the liberation of free neutrons and a substantial amount of energy. To illustrate this process visually, refer to the accompanying diagram of nuclear fission.

It is noteworthy that certain isotopes of heavy elements possess the ability to undergo spontaneous fission, although this occurrence is relatively rare. In such cases, the nucleus of the heavy element undergoes fission without external neutron bombardment, releasing energy and resulting in the formation of smaller nuclei and free neutrons.

Nuclear Energy

All matter has a nucleus at its core where the majority of its mass is concentrated. Under certain conditions, these nuclei can undergo transformative changes, giving rise to two fundamental processes: nuclear fusion and nuclear fission.

Both these processes share a common attribute – the release of a substantial amount of energy. But how does this remarkable phenomenon occur?Recall Einstein's equation, E = mc^2,

where:

E represents energy,
m symbolizes mass, and
c denotes the speed of light in a vacuum (299,792,458 meters per second).

While the mass involved may be small, the speed of light is a constant. By definition, nuclear energy is the energy liberated during nuclear reactions, such as nuclear fission or nuclear fusion.

Advantage and Disadvantage of Nuclear Energy:

One remarkable aspect of nuclear energy is its capacity to generate a substantial amount of power without the emission of pollutants. While the process itself doesn't generate pollutants during energy production, the radioactive byproducts require meticulous handling and storage.

Nuclear Fission in Power Plant

One of the most significant and positive applications of nuclear fission is in the generation of electrical power. Nuclear power plants utilize controlled nuclear fission reactions to produce heat, which, in turn, is converted into electricity. The process involves a series of carefully managed steps to ensure the safe and efficient use of nuclear energy.

In a nuclear power plant, uranium fuel rods undergo fission reactions, releasing a substantial amount of heat. This heat is used to produce steam by circulating water around the fuel rods. The steam, in turn, drives turbines connected to generators, generating electricity. The controlled nature of the fission reactions allows for a stable and continuous supply of electricity, making nuclear power an essential component of the global energy mix.

Summary

Nuclear fission is a splitting of an atom's nucleus, resulting in the formation of two smaller nuclei, free neutrons, and a substantial release of energy.
The uranium-235 nucleus absorbs a neutron, leading to the formation of barium-141 and krypton-92 isotopes.
One remarkable aspect of nuclear energy is its capacity to generate a substantial amount of power without the emission of pollutants.

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