Iran, proliferation and centrifuges

Iran, proliferation and centrifuges

Nuclear weapons are possessed by at least nine countries, posing a grave danger to humanity. The more countries that have them the greater the danger. At present there is real danger of uncontrollable proliferation with one country threatening to start a political chain reaction: Iran. Although it claims to be interested only in peaceful uses, power generation, there is good reason to distrust it. What is likely of greater danger is that its example could inspire other countries leading to a large number having nuclear weapons and then to disaster.

Before considering what should be done it is useful to understand some technical details. This is based on the article The gas centrifuge and nuclear weapons proliferation, by Houston G. Wood, Alexander Glaser and R. Scott Kemp, Physics Today, Sept. 2008, pp. 40—45 with physics background in the book by R. Mirman, Our Almost Impossible Universe: Why the laws of nature make the existence of humans extraordinarily unlikely (2006).

The nucleus of an atom consists of two types of objects (called nucleons), protons (which have electric charge, thus repel each other) and neutrons (which as the name implies are neutral). Objects are subjected to four types of interactions, gravitational (which are too weak to be relevant here), electromagnetic (electricity and magnetism are different manifestations), the weak interactions causing decay and the strong interactions by which nucleons attract each other (fortunately else nuclei would fall apart thus would atoms). The binding energy of a nucleus is a result of the attraction due to the strong interactions and the electric repulsions so that for nuclei with small numbers of nucleons fusing them gives more strongly bound nuclei plus extra energy (which can be used for very powerful bombs or if it can be controlled power), but ones with large numbers are weakly bound or unstable (too many protons, among other problems, so they repel). Thus fissioning them, breaking them apart, gives smaller, more strongly bound nuclei, plus extra energy, and this can be a large amount of energy. Iron is the most strongly bound, fusing lighter ones (realistically only much lighter) gives off energy, while fissioning heavier ones (realistically much heavier) gives off energy.

The heaviest naturally occurring element is uranium, thus it is the best one to use to get energy, particularly a bomb (plutonium with 239 nucleons, and also used for bombs, has to be manufactured). Because it is uranium it has (by definition) 92 protons but can have different numbers of neutrons, ones with different numbers are called isotopes of uranium. It is U(235), with 235 nucleons that fissions easily but natural uranium is mostly U(238), with three more neutrons these providing attractions making it more stable.

Natural uranium contains only 0.72% of U(235); for every thousand atoms of natural uranium only 72 are U(235). Thus to get fuel for a bomb this small amount must be separated from the uranium occurring in nature. The modern way is to use centrifuges.

To understand these we consider a keychain. If you whirl it around it flies off in a straight line. To make it go in a circle a force has to be applied, the centripetal force, supplied by your fingers supplied through the keychain. Add more keys and you can feel that the required centripetal force is greater, as it is if you whirl it faster. If you do not supply enough force it flies off. Thus the required centripetal force increases with mass and with speed. In a centrifuge the required force for the U(238) gas is greater than for the lighter U(235). There is also fluid flow of the gas within the centrifuge so the lighter isotope is carried to the top, where it is drawn off, leaving the heavier part at the bottom. The problem is that the masses of the isotopes are almost the same so that very high speeds are needed to separate them, but too high would mean that the walls of the centrifuge would fly off, destroying it. Thus a cascade is used. The first centrifuge produces a stream of slightly enriched U(235) which is fed into the second one, enriching it further, the result fed into the third centrifuge and so on until the U(235) is sufficiently enriched to be used in a reactor, or with greater enrichment a bomb.

What can be done? There are technical solutions to prevent sufficient enrichment for a bomb, like control of the uranium a country purchases, or inspection of the facility. But these basically require the acquiescence of the country. It isn’t difficult to get the uranium or enrich it if a country, like Iran, is determined to do so. The problem is not technical but political and psychological.

What are the dangers of Iran developing nuclear weapons? One unlikely one is an attack on Israel. The US has made it clear, and should emphasize strongly and explicitly again, that it would react to such an attack. An Iranian attack would lead to massive destruction in Iran. The Iranian leaders are evil but not insane. However possession of a nuclear weapon would give Iran great prestige and a psychological and domestic boost for its leaders (which is why it is desirable) and the prestige can be can be used to cause much trouble (as it has been doing but on a greater scale). Might it help Syria gain nuclear weapons? That is unclear but possible, and quite dangerous. Would the potentially unstable states want them if Iran, which is not trusted, had them? How about Sudan whose leader has been charged with war crimes? Might the dangerously unstable Pakistan be more willing to use such weapons, or sell them again? Would Hugo Chavez want them? And if Venezuela had them what about Columbia? And if middle-level Latin powers had them could the larger powers, Brazil, Argentina, and Mexico be held back? But if they had them, what about …? Of course terrorists would love to get nuclear weapons, and seem to be trying. That would be much easier if they were widely distributed.

Might we try to destroy Iran’s nuclear complex militarily? If we were sure that we knew where all of it is we might be able to that, easily. Many people thought it would be easy to remove Saddam Hussein, and it was. Are we happy with the consequences? Of course an attack on Iran would lead to far more, and far more serious, terrorism. And it would vastly damage US prestige, thus power, with very serious consequences. It is not a realistic option.

What can be done? And in this election year what do the candidates say? The details of their proposal are unimportant, but the thrust of their thinking is clear, and different. John McCain certainly recognizes the dangers and believes in increasing pressure on Iran. While that could be useful it is highly doubtful that such alone would be effective and might be counterproductive. It is essential to realize, not only with this, that one of the most powerful motivators is pride and prestige, People will accept severe punishment rather than give these up. Pressure, while useful if carefully done as part of a larger package, can make people unreasonably difficult, impossible to deal with, if it undermines their pride. This is true of everyone, starting with children.

Obama also recognizes the threat Iran poses. He does not emphasize the non-proliferation problem here but does emphasize it in broader terms, and it is much broader than Iran. He also stresses diplomacy and willingness to talk to people. The attitudes of Obama and McCain, not the less important specific details, are clear. McCain believes in pressure, essentially exclusively. Obama includes pressure as part of a strategy, but emphasizes talking, in general, and diplomacy, and the involvement of other countries, who have much at stake.

Psychologically being willing to talk to people, showing respect for them, is more likely to lead to positive outcomes than showing contempt (and the Bush-McCain world view tends, often strongly, to be contemptuous of others) and pressuring them. Often a combination of pressure and respectful discussion (which most accords with Obama’s outlook) is best. It requires understanding, knowledge and skill, these so lacking under Bush and clearly also for McCain, one of the reasons he emphasizes pressure exclusively.

One way of dealing with the Iranian problem is putting it in a broader context. We do not want Iran to acquire nuclear weapons. Do we want Saudi Arabia to? Egypt? Jordan, Brazil, Mexico, …? Yet as these weapons become more widespread they will become even more widespread. Stopping proliferation is essential. If not catastrophe becomes even more likely. If all nations were to forsake these would Iran? If more get them would Iran more likely do so? Iran is part of a larger problem, which makes it more difficult to deal with, but easier if the whole problem was.

While hopefully we can move to a world free of nuclear weapons we cannot have a nuclear-free world. The need for nuclear power is too great and it is already too widespread for that. The problem then is to have nuclear power while making it illicit to have nuclear weapons, increasing pressure to prevent that, including moral pressure which would increase if more nations were to forsake any attempts to gain weapons. Unfortunately this “more nations” includes the US.

Neither candidate has discussed this. Perhaps the present discussion will result in the question being raised. It is extremely important.

There is a fundamental question of attitude. While they have not considered this explicitly their attitudes seem quite clear. John McCain has the same outlook as George Bush, although perhaps not as extreme. That of Barack Obama and Joe Biden are very different. Bush’s attitude is that we are the most powerful nation in the world (or were when he took office) thus can do things, not only with this issue, that others are not allowed to. “We can …, but you must not.” Of course this does not work, nor could anyone expect it to (except for those guided by their fantasies). And there is no way we could have the power to enforce it. Thus we are left with no alternative but to lead, and we can only lead by example.

There must be international control of nuclear power, in particular nuclear weapons (which we must work to eliminate), nuclear power and nuclear material. The tools for manufacture, such as the centrifuges, must either be controlled by an international agency, or if there are national organizations these must be not only under international inspection but supervision to control the amount produced and where it is used. This must be true for all nations which unfortunately includes us. Psychologically this is very difficult. However irrational the opposition is, however much that opposition threatens our own survival, it will be psychologically almost impossible to accept. Consider that and we can see why it is so difficult to get Iran to give up its nuclear programs.

Yet that is what we must do to avoid disaster. It will require a long difficult process of education. This discussion is an attempt to add to that, but very much more needs to be done. Survival might be at stake.


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