What is The Difference between Nuclear Fission and Fusion?

Atom Bomb

As the search for renewable sources of energy that are environmentally safe continues, the idea of nuclear power has re-emerged as a possibility to reduce carbon emissions and address the long term problems of climate change. Fortunately, many people, especially those in business and government, are recognizing that the perception of “nuclear” doesn’t mean that the resulting power has to be destructive or dangerous. Gone are the days of fearing the possibilities of the infamous Three Mile Island disaster and Chernobyl nuclear plant catastrophes. As a matter of history, nuclear power has a stellar record of generating tremendous amounts of clean energy safely in the United States and other countries, such as France.

It is equally important to recognize that no single power source is free of problems. Wind power has limited potential and there are studies that show the windmills decimate some bird populations. As abundant and low cost as solar energy is, solar farms produce a tremendous amount of heat in the surrounding area, creating new problems in managing the environment. Also, solar panels are expensive to produce and are not suitable for every geographical area.

Turning to nuclear power, the process by which it is created here on Earth is similar to the process the Sun uses to create the abundant amount of solar energy scientists are currently trying to harness. That process is fusion, which actually is safer than the other process that is currently used to generate energy, fission. Fission also has some very difficult environmental problems to address, though they are fewer than the current carbon creating sources of coal and oil the currently supply most of the world’s power.

The basis of both processes begins with the famous German scientist Albert Einstein and his equally famous Theory of Relativity which is condensed into the scientific equation E=mc2. Rather than try to explain it here, all that is necessary to understand is that there is a relationship between energy (E) and mass (m). Energy we all understand. Mass is not weight but the amount of physical matter an object possesses. Your weight will be different on the moon and the Earth, but your mass is exactly the same.

Since fission is the process used to create energy in nuclear reactors, we will look at this process first. The word fission literally means “to break apart.” In common use the idea is more closely linked to “splitting” but for our purposes either mental image will work. What nuclear fission does is to split apart individual atoms with the result of releasing tremendous amounts of energy in the form of heat and light. You can go to YouTube and watch for yourself the effects of nuclear fission by watching the explosion of an atomic bomb.

It is the Theory of Relativity in action. The energy released in the form of heat and light is the result of the mass of the object, in the case the element Uranium, being changed or converted into heat, light, and sound energy. Using the real world example of the atomic bomb dropped on the city of Hiroshima, Japan, the physical weight of the Uranium was 140 pounds but its mass was 9,700 pounds. That doesn’t sound like much Uranium to create such a devastating effect, and it is the same basic process that takes place in a nuclear fission reactor. Of course, the reaction is controlled and there are a number of safeguards in place to prevent an uncontrolled reaction. The nuclear disasters that have been reported are all focused on the threat of radioactivity level causing harm to humans and the environment.

If it seems like a controlled fission reaction has few problems, you are correct. But those few problems have a large impact on the environment and last for literally thousands of years. The actual amount of Uranium that created the atomic explosion over Hiroshima was less than two percent of that 140 pounds. The rest of the Uranium became radioactive, and extremely dangerous to humans and the environment. Since 1945, science has devised ways to significantly reduce the amount of fissionable material required to use for a continued and controlled nuclear reaction. The major problem with a fission reactor is that a by-product of the process is radioactive Plutonium. Without getting too technical, just know that Plutonium is some really bad stuff. For starters, it is highly carcinogenic.

Which brings us to the second type of nuclear process, fusion. Where fission breaks apart the atoms in a mass of material, fusion tries to get two atomic particles to fuse, or meet, with the result of creating energy. Since this is not a chemistry lecture, the best way to think of it is to ask yourself how long it would take to find the perfect person to be in a relationship with you. The easiest and most obvious answer is “Someone who is exactly like me!” But the probability of you finding that person, then getting you to accept the reality of that situation is extremely low. The fusion in an atomic or nuclear process encounters similar problems.

One of the biggest problems is controlling the reaction when the two meet. In fission you can limit the amount of fissionable material and the number of atoms you are attempting to split. In fusion, you are joining two atoms of a material and creating a larger atom. The amount of energy created in this fusion process is between 3 and 4 times larger than that of a fission reaction, with the greatest benefit being that of the sole by-product of the reaction is harmless helium.

But turning the theory into practice is a far more difficult task. The Sun uses fusion to create the massive amounts of heat and light, and it works because the two components that are required for a fusion reaction are already present. The first is a gravitational field strong enough to get the two atoms to cooperate, and the second is an extremely high temperature. These scientific facts are easily seen when you realize that the Sun is about 93 million miles away, yet manages to keep the Earth within its gravitational pull and generates enough heat (and radioactivity) to fry an egg on the sidewalk or burn your unprotected skin.

For these reasons, creating a fusion reactor and managing all the problems connected with it is a far more complex problem than creating electricity by fission.

So why is this knowledge important?

The first and most relevant reason is that knowing there is an alternative source of energy to the fossil fuels of coal and oil will help address the issue of climate change over the long term. We are not likely to see fission fueled cars (the speed of those cars would be mind boggling) but as the world population grows and technology becomes common even in third world countries, the demand for electricity will continue to escalate. Advances in technology have significantly reduced the danger to humans and the environment. Even in the wake of the Japanese tsunami in 2011 when several nuclear reactors were damaged at Fukushima Daiichi, the net result was a limited impact on the environment while neither nuclear plant was compromised. Thus far, only one human death has been attributed to the disaster.

A second teachable moment here is that people can become more knowledgeable and less fearful of the potential of nuclear energy as an environmentally viable solution to global energy needs. It seems every alternative energy solution directly affects the surrounding environment. The issues that a fission reactor causes largely occur over a period of decades, not months. However you see the threat to the global environment, the simple reality is that the more time scientists and engineers have to work on fixing the existing problems, the more time we will have to address the future problems. This may not seem to be a perfect solution, but it is better than the alternatives which some projections have irreversibly affecting the planet in a few decades. The more we know and the more we learn, the more we can pursue a course of action based on scientific and technological knowledge, not on old stereotypes of everything connected to the word “nuclear” is to be feared.

Connected to the teachable moment of education about nuclear power is the need for STEM graduates who are capable of creating new solutions which harness the power of nuclear energy practically and safely. First, STEM graduates are almost always in demand and are offered high paying positions to make a socially positive impact on their community and the world. Not everyone is qualified to enter into a STEM major field of study, but this is even more reason for those who do have the aptitude to get involved. If you want to be someone who continues to lay the foundation for future innovation of alternative energy sources, you can opt to become a STEM teacher at both the high school and post-secondary education levels.

Addressing the potential of nuclear fusion needs to be recognized. While it is true that politicians and governments focus on the here and now, the future generations need to be confident that the technology that has been created by decades of innovation will have enough power to operate on a daily basis. Though invisible and ignored by most people, the amount of energy required to keep the Internet alive and accessible includes the electricity needed for servers, air conditioning units, and maintenance and growth of a reliable infrastructure. Producing all the electricity also costs money, and nuclear power is a very low cost source of energy. When you know that a fusion reactor has the promise of producing 3 to 4 times as much electricity as a fission reactor, you realize that fewer nuclear plants will be required, lessening the potential danger to humans and the environment.

You can ask yourself a question that is likely to show your potential as a future nuclear scientist or engineer. Did you find these explanations easy to understand? If you did, then you can move forward with confidence knowing that you have the potential to make a difference in the future of the planet. These are simplistic explanations of a very complex science. Not only is your potential important, but also your work ethic and your commitment to completing your formal education. Should you begin to walk a path that will confirm your abilities and interest in the potential of nuclear energy now and in the future, never forget that your classmates are also your teammates.

There are other fields of study such as Environmental Science that are not as technology intensive but make a significant contribution to solving the continuing problem of energy production. Most of us would rather plug in to an electrical outlet to charge our smartphones rather than continually have to change – and dispose of – batteries. That power has to be generated somewhere. We have to be careful not to ignore the reality that most of the things first world countries enjoy are the result of a viable and capable power grid. You don’t have to be a STEM major or graduate to understand this, but there are many other opportunities for you to make a small contribution to the solution.

The aim of this article was not to be a STEM recruiting tool or some type of pro-environment agenda. Reality dictates that nuclear energy and the long term problem of finding alternative energy sources continues to be a challenge. Most everyone should have taken away a basic knowledge of the potential, progress, and problems associated with the two types of nuclear reactions that can produce electrical energy. It is a forward looking solution that requires our attention for current and future generations.

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