北京大学附属中学道尔顿学院基础化学课程

Expansion of Nuclear Energy

Introduction

《Chemistry Revolution in Human Civilization》是针对高一、高二学过物理和生物的同学展开的基础化学课程。课程主要分成三个部分，第一部分是跟物理相关的原子结构探讨;第二部分是跟生物相关的食物科普类分享;第三部分是关于核化学知识的学习。在这门课上，基础知识的学习以辩论的形式展开的。在课堂中，同学们还阅读了一本化学相关的科普读物并做了相应的分享。

以下，我们选取了古时宁同学所做的关于本学期核化学学习内容的分享。

What is nuclear energy? Nuclear energy, or atomic energy, is the release of energy from the nucleus by nuclear reactions.

Nuclear energy can be released by one of three nuclear reactions:

1. Nuclear fission, the splitting of heavier nuclei to release nodule energy.

2. Nuclear fusion, in which lighter atomic nuclei come together to release nodule energy.

3. Nuclear decay, the release of energy in the spontaneous decay of the nucleus.

History

Nuclear energy is a great discovery in human history, which cannot be separated from the exploration and discovery of early Western scientists, who laid the foundation for the discovery and application of nuclear energy. Since the discovery of the electron by Thomson, a British physicist, at the end of the 19th century, the mystery of the atomic nucleus has been gradually revealed.

In 1895, x-rays were discovered by the German physicist Henri Rontgen.

In 1896, radioactivity was discovered by the French physicist Henri Becquerel.

In 1898, Madame Curie and Monsieur Curie discovered the radioactive element polonium.

In 1902, Madame Curie discovered the radioactive element radium after three years and nine months of hard work.

In 1905 Einstein proposed the formula for the conversion of mass and energy.

In 1914, the British physicist Rutherford, through experiments, determined that the nucleus of the hydrogen atom is a positively charged unit, called a proton.

In 1935, the neutron was discovered by the British physicist Charles Chadwick.

In 1938, German scientist Otto Hahn discovered nuclear fission by bombarding uranium nuclei with neutrons. On December 2, 1942, the University of Chicago successfully started the world's first nuclear reactor.

The United States dropped two atomic bombs on Hiroshima and Nagasaki in Japan on August 6 and 9, 1945.

In 1954, the Soviet Union completed the world's first commercial nuclear power plant, theOblingskNuclear Power Station.

In essence, the history and the process of how nuclear energy has been discovered are over above.

Resource

Let’s take an example from the resource of nuclear energy. “The United States has 104 commercial nuclear power plants in 31 states, which produce 20% of the country's electricity”(Palliser 14). We may conclude that the United States has the most nuclear power plants in the world. So where does the resource come from? Well, in specific, “Nuclear plants use uranium(uranium-238 and uranium-235)in the form of solid ceramic pellets...Thepellets are bombarded with neutrons, causing the uranium atoms to split(fission)and release heat and neutrons. These neutrons collide with other uranium atoms and release additional heat and neutrons in a chain reaction”(Palliser 14). Therefore, we know that nuclear power plants use the chemical element uranium to release energy.

Here comes up a question, why do the plants choose Uranium? Uranium is a radioactive metallic element that can be used as fuel for nuclear reactions. It is a silver-white metal, almost as hard as steel, and has a high density. Before the development of nuclear energy, it was used to make yellow glass.

The reason for being chosen might be that Uranium is the element with the highest atomic number found in nature. By contrast, it is almost the heaviest element in nature, and its nucleus is so unstable(and naturally decaying)that neutrons bombard the nucleus so quickly that it splits apart. Other heavy elements find it difficult to meet the conditions that humans can create.

Advantage

Advocates of nuclear power cite its clean energy-nuclear power plants do not emit carbon dioxide, sulfur dioxide, or nitrogen oxides(EPA 2010). Large amounts of electricity can be generated in a relatively small space with less land than other energy sources.

Disadvantage

From a health perspective, if ingested or inhaled, uranium's radioactivity increases the risk of lung and bone cancers.

From the financial perspective, the cost of building a new power plant is about $4 billion, though costs often increase during the construction process, making the actual cost much higher(Schoen 2007).

From the environmental perspective, Uranium is a non-renewable resource. And the equipment in the plant has been contaminated with radiation for so long that it becomes radioactive waste once the plant is shut down.

Nuclear Accident

On April 26, 1986, an operator error caused two explosions in reactor number 4 at Chernobyl nuclear power plant in the former Soviet Union. The reactor had an inadequate containment building; large amounts of radiation escaped(U.S. DOE 1994). According to the World Health Organization, 28 people died in 1986 due to acute radiation sickness(2006). There has been a large increase in thyroid cancers in people who were children or adolescents at the time(and lived in the most contaminated areas)due to exposure to radiated iodine.

Conclusion

With the rapid development of science and technology, scientists are constantly exploring the potential of nuclear energy. We should carefully consider how to properly use nuclear energy and promote social development based on the realistic environment and humanistic concern.

Reference

[1]Palliser, Janna. “Nuclear Energy.”Science Scope, vol. 35, no. 5, National Science Teachers Association, 2012, pp. 14–18,http://www.jstor.org/stable/43184528.

[2] Argonne National Laboratory and U.S. Department of Energy(DOE). Is uranium radioactive? http://web. Ead.anl.gov/uranium/faq/uproperties/faq

[3] Environmental Protection Agency (EPA). 2010. Nuclear energy, www.epa.gov/cleanenergy/energy-and-you/ affect/nuclear.htm

[4] Energy for educators- www.energyforeducators.org/lessonplanstopic/nuclear.shtml

[5] Energy kids: Uranium- www.eia.gov/kids/energy.cfm?page=nuclear_home-basics

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