A nucleus is tiny, but very heavy for its size, because the material that makes up a nucleus is extremely compressed. When a nucleus is split — a process called ‘fission’ — it gives off energy in a form that can cause nearby nuclei to also split. If the right type and amount of material is involved, this fission can cause an incredibly powerful and fast chain reaction.
It is this power that scientists have only managed to use in modern times. Properly controlled, the energy of the atomic nucleus can be used to generate electricity, to assist in medicine, and to make special radioactive materials with benefits in agriculture, industry and water management.
But the explosive energy of the nucleus has also been used to make bombs — bombs far more powerful than humans had ever invented before. It is this potential for massive destruction that makes nuclear issues so important to international security.
2. How different are nuclear weapons from other types of weapon?Nuclear weapons are different in two main ways. First, they are many times more powerful than any other type of gun, cannon, bomb or explosive. The first time a nuclear weapon was used in a war situation, over the city of Hiroshima, Japan, more than 70 000 people were killed in a matter of seconds — and many more died from the intense radiation effects.
The second difference is that nuclear weapons are much harder to make than other types of weapons. Each weapon requires a significant amount of “fissionable” nuclear material: either uranium that has been “enriched” through a special process; or plutonium, a metal that does not occur in nature, and can only be produced artificially using a nuclear reactor. The process of creating these materials — plutonium or high enriched uranium — has been mastered by relatively few countries, and it is one of the hardest steps in making a nuclear weapon.
Even with the needed amount of nuclear weapon material on hand, making that material into a nuclear weapon is not easy. It requires sophisticated engineering designs and skills.
3. How many nuclear bombs are there in the world today?There are five countries with nuclear weapons that are part of the Nuclear Non-Proliferation Treaty — China, France, Russia, the United Kingdom and the United States. Together, they possess about 27 000 nuclear warheads. In my view, this is 27 000 too many.
The United States and Russia control about 95 percent of these warheads.
Three countries - India, Pakistan and Israel - have not joined the Treaty and have or believed to have nuclear weapons. North Korea also says it has produced nuclear weapons, but no other country or international organization has been able to verify this.
4. How did things get so bad?Nuclear weapons were invented during World War II. The United States was the first to develop these weapons; the Soviet Union was second; and other countries began to follow suit. Today we have an environment of insecurity, in which some additional countries believe that possessing nuclear weapons would be like an insurance policy — that would prevent any other country from attacking them.
In the case of the United States and Russia, a competition developed to build bigger nuclear weapons — including “thermonuclear” weapons, which combine the power of fission and fusion, and can be thousands of times more powerful than the atomic bomb that destroyed Hiroshima. The competition was also to see who could build the most weapons, and the best missiles for delivering these weapons to a target.
The idea was to create a “stand-off” — a situation in which neither country would actually dare to use such a weapon, for fear of being destroyed in return. The name given to this stand-off was “Mutually Assured Destruction”, abbreviated as “MAD”.
But the result is that we now have many thousands of these horrifying weapons — and now that they exist, they have become a liability, a threat to our survival.
It’s important to remember that there is also some good news. Several countries that once had nuclear weapons or nuclear weapons programmes — like South Africa, Ukraine, Belarus, and (most recently) Libya — have voluntarily given up these programmes.
And over the past 20 years, the world has made some progress in “nuclear disarmament” (the process of getting rid of nuclear weapons). In 1985, there were about 66 000 nuclear weapons in the world. Now we have less than half that number. But we still have a long way to go.
5. Since the United States and Russia have the most nuclear weapons, are they the countries you're most worried about?In my view, any country that has nuclear weapons is a cause for worry — whether the number of weapons is 10 or 10 000. Any government can change its security strategy. Any weapons control system can have imperfections. And if a nuclear weapon were ever again used — even by mistake — the consequences could be terrible, regardless of what country it came from.
Another big worry for me is terrorism. If a terrorist group managed to get hold of a nuclear weapon — or even a less powerful “radiological” weapon, which we sometimes call a “dirty bomb” — I think there is a good chance they would actually use it. So it is extremely important that these weapons and materials are kept very secure.
6. What challenges do you face in trying to stop the spread of nuclear weapons?The International Atomic Energy Agency works to make sure that nuclear material is only used for peaceful purposes, and not used for making nuclear weapons. We monitor 900 nuclear facilities in more than 70 countries — but in order to succeed, we need the help of every single country.
One challenge we face is that modern technology spreads more easily than in earlier times. The use of the Internet, modern communications, and global trade and travel has made it much harder to keep sensitive nuclear technology from spreading. This, in turn, makes it harder to ensure that no one is working to develop nuclear expertise in secret.
Another even bigger challenge is that, unfortunately, the ownership of nuclear weapons has become more attractive. Because some countries have these weapons, other countries who feel insecure or want to project their power may also want to have them. And as long as nations continue to feel insecure, the process of “nuclear disarmament” goes very slowly.
7. It sounds like a big job. How much help do you get from world leaders, and what else do they need to do?I get a lot of help. World leaders from nearly every nation take nuclear issues very seriously, and are eager to find solutions to the nuclear threats we face. The problem, of course, is that not everyone has the same view about how to fix these problems.
One step I have proposed is to change the way we control the processes to produce sensitive nuclear material. Processes like uranium “enrichment” are needed for legitimate uses of nuclear energy — such as making nuclear fuel to generate electricity. But we could reduce the risk of “proliferation” (in which new countries would use nuclear material to make bombs) if these processing centres were put under multinational control, rather than being under the control of a single country.
Another very basic need is for countries to get more involved in developing peaceful solutions in regions like the Middle East and South Asia. These regions have a lot of insecurities — due to conflicts, distrust and fear that go back for many decades. And these insecurities, over time, can lead the countries involved to seek nuclear or other powerful weapons. By working harder on peaceful solutions to these problems, we could reduce the motivation for seeking such weapons.
8. Do you think scientists made a huge mistake when they tinkered with atoms and invented nuclear bombs?Of course I would wish that nuclear bombs had never been invented.
But I would characterize the problem differently. I would say that our “technical intelligence” — the brainpower that we focus on technological advancement — has grown much faster than our “social intelligence” — the intellectual effort we make to deal with social issues, including global insecurity.
We cannot change history, and “un-invent” nuclear weapons. But we can work harder on our social intelligence, to become smarter about how we can live together as one human family.
