Features

On the road to achieving net-zero by midcentury, low- or no-carbon energy sources that slash carbon dioxide emissions are critical weapons. Nevertheless, the role of nuclear energy—the single largest source of carbon-free electricity—remains uncertain.

Nuclear energy, which provides 20 percent of the electricity in the United States, has been a constant, reliable, carbon-free source for nearly 50 years. But our fleet of nuclear reactors is aging, with more than half of the 92 operating reactors across 29 states at or over 40 years old—the length of the original operating licenses issued to the power plants. While some reactors have been retired prematurely, there are two options for those that remain: retire them or renew their license.

President Biden signed the Infrastructure Investment and Jobs Act (IIJA) into law in November 2021. Commonly known as the “bipartisan infrastructure bill,” this legislation included significant investments in civilian nuclear energy in the U.S. along with a range of other spending initiatives. The law directs funding to preserve the operation of nuclear plants facing the prospect of early closure, demonstrate new advanced reactors, and explore the ability of nuclear energy to produce hydrogen for other energy applications. Additional incentives to retain and expand the use of nuclear energy are still being considered in Congress, but the IIJA is law, and the Department of Energy is beginning the process of implementing its key provisions.

Artificial intelligence (AI) and machine learning (ML) are helping scientists, engineers, regulators, and plant decision makers in their research and development of clean energy production to achieve a net-zero carbon footprint. While this science is new in terms of actual applications, it is fostering innovation in a variety of domains, from material discovery and qualification to advanced reactor design to supporting efficiencies in current power plants and transforming the usability of nuclear power plant control rooms.

The world needs scientists, engineers, and technologists to ensure the safe, secure, and sustainable use of nuclear energy to meet global energy demands and environmental challenges. Yet, in many countries there are concerns about the potential loss of nuclear expertise and knowledge because of changes in workforce demographics. Much of the tacit knowledge in the sector was generated during the pioneering years of nuclear power. During this period, R&D projects and innovative construction projects were ramping up, and many nuclear power plants were being built. As a result, personnel in the industry were confronted with challenging and groundbreaking projects, as well as the risk of failure. It is this knowledge that is most difficult to harvest and is generally transferred via hands-on experience. In the current nuclear power landscape, where R&D spending is decreasing and innovation slows down as a general trend, this knowledge risks being lost if there are fewer opportunities to acquire hands-on experience work on challenging projects.

Fusion energy is attracting significant interest from governments and private capital markets. The deployment of fusion energy on a timeline that will affect climate change and offer another tool for energy security will require support from stakeholders, regulators, and policymakers around the world. Without broad support, fusion may fail to reach its potential as a “game-­changing” technology to make a meaningful difference in addressing the twin challenges of climate change and geopolitical energy security.

The process of developing the necessary policy and regulatory support is already underway around the world. Leaders in the United States, the United Kingdom, the European Union, China, and elsewhere are engaging with the key issues and will lead the way in setting the foundation for a global fusion industry.

Interest in reducing carbon emissions around the world continues to climb. As a complement to the increasing deployment of variably generating renewables, advanced nuclear is commonly shown in net-zero grid modeling for 2050 because it represents firm electricity production that can flex in output with load demands.¹ However, these projections are challenged by the high levelized cost of electricity associated with legacy nuclear construction, which is often more than double that of modern combined-cycle gas turbine (CCGT) plants.

The United States has just 93 operating power reactors at this writing. The fleet last numbered 93 in 1985, when nuclear generation topped out at 383.69 TWh, less than half of the 778.2 TWh produced in 2021.

While the 93 reactors operating today have more capacity, on average, than in 1985, most of that increased productivity is down to operational improvements that pushed the fleet’s average capacity factor from just 57.5 percent in the three-year period 1984–1986 to near 90 percent by the early 2000s.

Part one of this article, published in the May 2019 issue of Nuclear News[1] and last Friday on Nuclear Newswire, presented insights from the 1979 accident at Three Mile Island-­2 and addressed several issues raised by a previous Nuclear News piece on the accident[2]. Part two discusses safety improvements that have been made by both the industry and the Nuclear Regulatory Commission over the past 40 years.

The Waste Management Symposia, the premier forum on the management and disposition of radioactive waste, took place in person this year March 6–10 in Phoenix, Ariz., after being held virtually in 2021 due to the COVID-­19 pandemic. With more than 2,100 paid participants, the prevailing feeling at the conference was one of getting back to normal after two long years without face-­to-­face contact.

The accident at Unit 2 of the Three Mile Island nuclear power plant on March 28, 1979, was an extremely complex event. It was produced by numerous preexisting plant conditions, many systemic issues in the industry and the Nuclear Regulatory Commission, unanticipated operator actions, previously unrecognized thermal-­hydraulic phenomena in the reactor coolant system (RCS), and the unprecedented challenge of managing a severely degraded core.