A nuclear reactor

Learn about nuclear energy

The intrigue of nuclear

Of all the known energy resources, nuclear is perhaps the most passionately debated and least understood. Our goal is to explain what makes some people so excited and supportive, and what makes others so passionately opposed. There are many sides to each story. Let’s explore them.

Energy is part of a historic process, a substitute for the labor of human beings. As human aspirations develop, so does the demand for and use of energy grow and develop.

David Lilienthal Atomic Energy: A New Start, Harper & Row, 1980, p. 10.

Humans use a lot of energy, and we’re using more every day. Between 2000 and 2010, the world total energy consumption rose by an astounding 29% [1]. Choices about our consumption of energy are fundamental to the primary geopolitical and environmental struggles of our day. Nuclear energy is a strong candidate for supplying our energy while alleviating these struggles.

In late 1938, the great physicist Lise Meitner and her nephew correctly interpreted the shocking results from a recent experiment as the splitting of uranium atoms. They named the process fission. Since then, machines (nuclear reactors) that control large-scale fissioning of atoms and harvest the vast amounts of heat that’s released have been designed and built.

The remarkable thing about fission is that you can get about a million times more energy from fissioning a handful of nuclear fuel than you can get from burning a handful of any traditional fuel (like coal). That is, the energy density of nuclear fuel is astoundingly large. The implications are many. For example, if you use nuclear reactors instead of burning traditional fuels,

  • you only have to dig up a millionth of the resource out of mines,
  • you only produce a millionth of the waste,
  • you only need a millionth of the traincars and trucks to deliver fuel,
  • a stockpile of fuel of a given size will last a million times longer,

and so on. This incredible energy density allows the waste to be fully accounted for and contained, whereas traditional energy sources dump their wastes directly into the atmosphere, so nuclear reactors provide great air quality and very minimal carbon emissions. We know there is enough nuclear fuel available to power the world for thousands of years. Furthermore, reactors can operate continuously, day and night, windy or calm, snowstorm or heat wave, for years on a single fuel loading.

Arguments against nuclear

Of course, there are downsides to extracting energy by splitting atoms in reactors. The arguments against doing so fall into 4 categories:

nuclear waste


When heavy atoms fission and release energy, the two smaller atoms remaining (called fission products) are often left in elevated energy levels. This energy is released over a period of time (from seconds to hundreds of thousands of years) in the form of energetic particles called radiation. The radiation is very dangerous and must be kept isolated from the biosphere. While technical solutions exist to dispose of or otherwise reduce the waste, we have not yet agreed on what should be done with it.

Read more about waste »

fire extinguisher


The radioactive fission products are hottest when a reactor first shuts down. In effect, you can’t shut a reactor completely off. This decay heat must be cooled or else the containment structures that hold the fuel and waste can breach, releasing radiation into the biosphere. Accidents at Fukushima and Three Mile Island were caused by this effect. Unstable reactor design and operation at Chernobyl led to a power excursion and widespread dispersal of radioactive material. So, people worry about reactor safety.

Read more about safety »

fat man


The first application of fission was as an atomic bomb. While nuclear reactors and atomic bombs are very different machines (and a reactor can never explode like a bomb), there is some technology overlap, especially in fuel cycle facilities like enrichment and reprocessing plants. So, some people argue that having reactors around might make it easier to spread nuclear weapons.

Read more about proliferation »



Nuclear reactors are generally large and complex, with lots of reinforced concrete and nuclear-grade quality assurace programs. As a result, they tend to be expensive to build. Once they’re built, the fuel and operating costs are relatively cheap, but the capital cost is a major hurdle.

A nuanced reality

Like every other energy source, nuclear energy has both good aspects and bad. However, its ability to responsibly produce global-scale, 24/7, (nearly) carbon-free energy is unmatched among known technolgies. Nuclear waste needs political will to be dealt with, but there are safe ways to dispose of it. As for reactor safety, while the accidents that have occurred are high profile and memorable, the actual risk to public health is very small compared to most of the alternatives.

Next-generation reactor designs exist that can reduce waste, improve safety, increase proliferation resistance, and reduce costs. Even if someone doesn’t support current nuclear, it is silly for them to disregard all possible improvements. We humans have done pretty impressive stuff in the past.

Where to go from here

This front page is just a teaser for the vast amount of other content we provide. Take a look at the navigation bar on the top of the page (or click the line-icon if you’re on a small screen). You’ll find information on all sorts of relevant topics. To get started, head over to the nuclear energy page for more details about the pros and cons, or check out the what is a nuclear reactor? page.

Other highlights include


  1. International Energy Outlook , US Energy Information Administration (2013).