Monday, October 20, 2008

Ethics of Career Choice: Nuclear Engineering

Since most engineers are not self-employed, the type of work they do is largely determined by the organizations they work for. This means that one of the most ethically significant decisions engineers make is deciding on what job offer to accept. These days, it may seem like finding any engineering job at all is a challenge, but even in the worst of times you are still free to choose where to look for work. Today I'd like to show how you can begin to work through the ethical implications of a whole field of work, namely, nuclear engineering.

Only a small number of nuclear engineers design bombs, but the fact that the first application of nuclear fission was to kill thousands of Japanese in and around the cities of Hiroshima and Nagasaki in World War II has cast its shadow over the field ever since. There are those who are unalterably opposed to any use of nuclear energy, peaceful or otherwise. They argue that besides the danger of nuclear-weapons proliferation, the problem of nuclear waste hasn't been solved and the danger of a Chernobyl-type accident is too great to allow any further growth of nuclear power. (Chernobyl was the name of a city in the present country of Ukraine, then the USSR, near which a nuclear power plant exploded and caught fire in 1986, spewing tons of radioactive material over the countryside and forcing the evacuation of hundreds of thousands of people.)

On the other hand, both current U. S. Presidential candidates favor at least some expansion of nuclear generating capacity in the U. S. as a way of decreasing the nation's dependence on foreign oil. Nuclear generation releases essentially no greenhouse gases such as CO2, in contrast to the burning of fossil fuels such as oil or coal. Proponents argue that the waste problem is manageable and point to countries such as France that generate most of their electricity with nuclear-powered facilities.

You may have heard someone say that technology is ethically neutral, it's what human beings do with technology that makes for good or bad consequences. Most of the time, that view is at least an oversimplification, but it turns out to be almost exactly true of a particular kind of nuclear-related technology: the gas centrifuge. Naturally occurring uranium does not have a high enough percentage of the isotope U-235 to be useful either in nuclear reactors (which need slightly enriched uranium) or weapons (which need almost pure U-235). It turns out that the most efficient way to increase the fraction of the lighter U-235 isotope in uranium, compared to the heavier U-238 one, is to turn it into a gas by attaching six fluorine atoms to each uranium atom, and send the gas through an extremely high-speed centrifuge in the form of a hollow aluminum cylinder spinning in a vacuum. You need hundreds of these centrifuges to do the job, but they can be as small as only six feet high, and a centrifuge plant uses only about as much energy as a food-processing plant of the same size. The very same plant can be used either for making slightly enriched uranium for peaceful nuclear reactors, or highly enriched uranium for bombs.

This is one reason why Iran's gas-centrifuge facilities are so controversial: Iran's government says it's for peaceful applications, but the International Atomic Energy Agency inspectors know the same facility could be used to make bomb-grade material. It all depends on what the engineers do with it.

We've only scratched the surface of what is clearly a complex and multifaceted issue. One of the world's most infamous parties in nuclear proliferation, a metallurgist named Abdul Qadeer Khan, turned his knowledge of gas centrifuges toward making plans available for black-market buyers such as Iran and Libya. Khan is a bad example of how technical knowledge can be abused, but even that viewpoint might be debated by some of the people in countries that benefited from his expertise.

Perhaps more than most other fields of engineering, nuclear engineering is fraught with ethical questions: What products are made? How safe are the facilities being designed? What are the long-term consequences of use for future generations? Young people who are uncomfortable dealing with these issues may consider other fields instead. But the field needs some good engineers—both in a technical and an ethical sense—if the benefits of the technology are to be realized with a minimum of harm.

Personally, I would like no better outcome concerning America's energy situation than if we built a bunch of safe, uniform, French-style nuclear plants, junked our gas-guzzling nineteenth-century internal-combustion cars, replaced them with electrics charged from the nuclear-powered grid, and got in a position to thumb our collective noses at foreign oil producers. But a lot of things would have to change before that vision is realized, and a lot of nuclear engineers would be involved in the change.

Sources: The September 2008 issue of Physics Today carried an informative article by H.G. Wood, A. Glaser, and R. S. Kemp on the gas centrifuge and its role in nuclear-weapons proliferation, pp. 40-45.

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