Over the last two days I had a pleasant exchange with a 7th grader from California who wanted to know more about nuclear energy for a school project. He asked me about a dozen questions on nuclear power and I answered them. It was instructive to realize how I needed to formulate my own words to make sure my responses were simple, brief and intelligible to an intelligent middle schooler. Although a few big words have inevitably crept in I think I have kept the majority of answers simple and straightforward; it was certainly a fun thing to do.

One thing that struck me was how cogent and clear the questions are. They are certainly a testament to the thoughtful consideration which my correspondent and his parents have given to the topic. But it also struck me that they are exactly the kinds of questions which curious laymen who know little about nuclear power may ask (another one of those instances where an intelligent 7th grader is quite a match for an intelligent adult layman). So I added a few of my own and answered them too. I think cases like these where you are constrained to give short and simple answers to scientific questions are not only a good exercise in improving your own understanding of topics but are also a good resource for public education. As Niels Bohr used to say, whatever you want to explain you should be able to explain using plain language.

I do hope that more middle schoolers consider science and engineering careers in energy in general and nuclear energy in particular; responsible future citizens who tackle the energy crisis head on are crucial to this country's development . Here are the questions and answers, in no particular order.

What are reasons that prove nuclear energy is not the best alternative to replace fossil fuel?

A: Nuclear energy is actually a pretty good replacement for fossil fuels. It emits very little CO2 and other pollutants and provides a lot of energy from a very small amount of fuel. It also generates a very small amount of waste. Compared to this, coal and oil produce a lot of air pollution and waste and you also need a lot of them to generate electricity.

Despite the low cost of running a nuclear power plant, will the expensive cost of making the nuclear power plants make people think about not funding for the nuclear power plants? Why?

A: The expensive cost of nuclear power plants comes from the very long time that is needed to build them; one reason they take so much time to build is because you want to ensure that they are safe, which is a good thing. However there are new power plant designs which promise to shorten this time and reduce the expense. There is especially a new and exciting reactor called the “small modular reactor” which is small and quickly built. In addition you have to balance the cost of power plants against the cost of electricity from them (which is quite low), the small amount of pollution that they cause and the other benefits which they provide over fossil fuels.

Are there any other alternatives of energy instead of nuclear energy?

A: Yes, some other alternatives to nuclear energy include geothermal energy (energy derived from heat inside the earth), solar and wind energy. All these sources are promising but since the sun does not shine all day long and the wind does not blow all the time, they cannot provide as reliable and powerful a source of electricity as nuclear energy. In addition the technology to use these alternatives on a large scale is still not highly developed. Also, natural gas is a somewhat better alternative than coal and oil since it releases fewer greenhouse gases.

Why might there be a risk of dangers when using nuclear energy?

A: The risk of using nuclear energy comes from the possibility that radioactive elements might be released into the environment. However nuclear power plants are very carefully built to prevent such releases. Nuclear energy has a very good safety record and hundreds of nuclear power plants all over the world have operated for more than fifty years without any serious accidents. Even the two worst nuclear accidents in history (Chernobyl and Fukushima) have harmed very few people compared to the pollution from fossil fuels. In fact there are people and animals living around Chernobyl who are in excellent health.

Can nuclear reactors in nuclear power plants have a harmful affect on humanity if ever any mistakes happen? Why? Does the radiation coming from the nuclear power plants be a major down side of using nuclear energy? Explain.

A: Yes, a release of radiation from a nuclear reaction can have some harmful effects on the health of human beings. Depending on the circumstances of the accident, the radiation can affect cell division and can potentially lead to diseases like cancer. However nuclear reactors have been constructed to a very high safety standard. Only two nuclear reactors out of several hundred (Chernobyl and Fukushima) have had serious accidents, and all the research done until now tells us that the radiation released from them has harmed very few people compared to pollution from fossil fuel plants and other accidents such as mining and automobile accidents. Thus nuclear power has had very little harmful effects on humanity until now.

How can the unsolved problem of nuclear waste disposal affect the use of nuclear energy?

A: The problem of nuclear waste disposal is challenging but it is not unsolved. For starters, the total amount of nuclear waste from all reactors is extremely small and can be placed in a 3 meter pile on a single football field. In addition only a small part of that waste is long-lived. Thus we can separate that part from the short-lived waste which will disappear soon. We can also use some of the waste in generating more electricity from nuclear reactors.

Is nuclear energy the best replacement to fossil fuel? Why or why not?

A: Nuclear energy is certainly one of the best replacements for fossil fuels. It generates a lot of energy from a very small amount of fuel, emits very little CO2 and other harmful pollutants and has a very good safety record. In fact it has saved a lot of lives in the past which may have been lost had we built fossil fuel plants instead of nuclear reactors. The problem of radioactive waste is challenging but can be solved if we separate and re-use the waste.

Will the high amount of security needed at nuclear power plants play a role on the dangers of producing nuclear energy? Why?

A: Nuclear power plants don’t need as much security as you would imagine. The fuel used in nuclear reactors is not easily accessible if someone wants to steal it. In addition the fuel is highly radioactive so anyone who tries to steal it runs the risk of being greatly harmed by the radiation. Thus security at nuclear power plants by itself will not pose a problem in using nuclear energy.

Will there ever be a safe way to produce and use nuclear energy? Why or why not?

A: Yes. The nuclear energy that has been produced in the last fifty years has been very safely produced and used. There is also a lot of new research going on into reactors that are even more powerful, smaller and safer. We will always have to make sure that we don’t accidentally release radiation from a nuclear reactor, but until now we have been very successful in preventing a deadly radiation release so there is little reason to believe that things will be different in the future.

Why are some people afraid of nuclear power?

A: People are generally afraid of things they can’t see and touch, such as radiation. In addition you hear a lot about the rare nuclear accident in the papers compared to the more frequent car accident or shooting because of which many more people die. In addition many people are not very familiar with the advantages of nuclear power and thus are suspicious of it. Also, some folks think of nuclear bombs when they think of nuclear reactors although the two are completely different; a nuclear reactor can never explode like a bomb.

How does a nuclear reactor work?

A: A nuclear reactor is basically a machine for generating heat. The heat comes from the splitting of the nuclei of atoms in two elements: uranium or plutonium. The heat is carried away by a coolant like water which is used to drive a turbine that generates electricity.

How are nuclear reactors made safe?

A: Many factors contribute to a safety of a nuclear reactor. The nuclear material itself is very well shielded and the reactor is covered with a huge dome that will not allow radioactive material to escape. There are also many backup systems that prevent radiation release; if one fails another takes over. Nuclear power plants release very little radioactivity during their normal functioning; in fact you get more radioactivity from eating a banana than by living near a nuclear reactor! Many people in the US and all over the world live nuclear power plants without any problems.

Can the material from a nuclear reactor be stolen by a terrorist to make a bomb?

A: It would be highly unlikely for a terrorist to steal material from a nuclear reactor and make a bomb with it. The material is usually very well shielded, it is contaminated with other undesirable materials which have to be separated, and the amount of radioactivity is very high. A terrorist would risk his life when stealing such highly radioactive material, and the time it would take for him to do this would probably be more than enough for the police to get there and capture him.

Is all radiation bad?

A: No, all radiation is not bad, only high levels can sometimes cause harm. One important thing to remember is that radiation is not something only associated with nuclear power; we are surrounded by radiation at all times. We get radiation when we do an x-ray test, when we travel in airplanes and when we eat bananas. These low levels of radiation are all safe for you; so are those that you get from living around a nuclear power plant.