16. Nuclear Reactor Construction and Operation

The paragraph introduces the concept of nuclear energy and its benefits, highlighting the role of MIT OpenCourseWare in providing educational resources. It also mentions the TA's role in teaching the lesson and provides a brief history of nuclear energy development, from early scientific discoveries to the Manhattan Project, and the eventual shift towards using nuclear energy for peaceful purposes like electricity generation. The timeline includes key developments like the first nuclear reactor, President Eisenhower's 'atoms for peace' initiative, and the launch of the first nuclear-powered submarine.

This paragraph discusses the sustainability of nuclear energy as an alternative to fossil fuels, emphasizing its low carbon footprint compared to coal and natural gas. The TA presents statistics to show that nuclear power produces significantly less carbon emissions. Additionally, the paragraph covers the high energy output of nuclear reactions and the reliability of nuclear power as a baseload energy source, which can continuously produce energy regardless of weather conditions unlike solar or wind power.

The TA explains the different types of nuclear reactors, categorized into generations, and focuses on light water reactors (LWRs), which are the most common in the United States. The explanation includes boiling water reactors (BWRs) and pressurized water reactors (PWRs), their mechanisms, and their pros and cons. The paragraph also touches on heavy water reactors, specifically the CANDU reactor in Canada, and the advantages of using heavy water due to its lower absorption cross-section, which allows for the use of lower enriched uranium.

This section delves into breeder reactors, which are designed to produce more fissile material than they consume. The TA explains the concepts of fissile, fissionable, and fertile materials, and how breeder reactors use additional chunks of uranium-238 and thorium-232 to create more fuel. The process involves neutron absorption and subsequent transformations through beta decay to produce plutonium-239 and other fissile materials. Despite the theoretical benefits, breeder reactors have not been widely adopted due to practical challenges and the discovery of more abundant uranium resources.

The TA discusses the current state of nuclear power in the US and globally, noting that it provides a relatively small percentage of total electricity production. The paragraph addresses the social, economic, and governmental hesitance towards nuclear power, primarily due to safety concerns highlighted by major nuclear accidents like Three Mile Island, Chernobyl, and Fukushima. Each accident led to a decline in the construction of new reactors. The TA also briefly touches on the next generation of reactors that are being explored for their potential safety, efficiency, and sustainability benefits.

This paragraph provides a detailed account of three major nuclear accidents: Three Mile Island, Chernobyl, and Fukushima. The TA explains the causes and consequences of each accident, including the mechanical failures and human errors that led to core meltdowns and explosions. The discussion includes the release of radioactive isotopes into the environment and the resulting health and environmental impacts. The TA emphasizes that while these accidents were severe, they were also rare, and the overall safety record of nuclear power is better than it is often perceived.

The TA addresses the challenge of nuclear waste management, focusing on spent fuel from reactors. The paragraph outlines the primary methods of storing spent fuel, including spent fuel pools and dry cask storage, and their limitations due to space constraints and long-term radioactivity. The discussion also touches on the concept of deep geological repositories, such as Yucca Mountain, which was explored as a permanent disposal solution in the US but was ultimately abandoned due to geological concerns and social opposition. The TA concludes with the idea of repurposing spent fuel, which is practiced in some countries but not in the US due to high costs.

The final paragraph discusses the economic challenges that hinder the widespread adoption of nuclear power. The TA explains that the high capital costs associated with building nuclear reactors, including the time and money required, are the primary barriers. The costs of fuel, operation, and maintenance are relatively low compared to the capital costs, making nuclear power less competitive with other energy sources. The TA concludes by encouraging further exploration of nuclear energy topics through additional resources and courses.