Nuclear terror facts

Following the attacks of September 11, there has been much concern about further acts of terrorism, with nuclear terrorism heading the list. For some reason, the public seems to be more afraid of radioactivity than poison gas or even biological agents. This even though radioactivity is easy to detect, rarely lethal and cannot cause epidemics as can viruses or bacteria. This fear is being exploited by opponents of nuclear power who keep coming up with a multitude of scary scenarios.

     Three general types of nuclear terrorism are much in the news: One is the so-called "dirty" bomb, which does not create but simply disperses radioactive material, packed around conventional explosives. Another concern is release of radioactivity from an aircraft impact or the internal sabotage of an operating nuclear reactor or of storage of highly radioactive spent nuclear fuel. Green activists, who would love to shut down reactors, assiduously promote this particular fear.
      Finally, we have the possible explosion of a nuclear bomb. Of the three, the dirty bomb makes no sense at all; impact or sabotage is extremely unlikely to succeed. Only a real nuclear bomb using fissionable uranium or plutonium poses a serious threat, but even there countermeasures can be taken.
     The dirty bomb is mostly hype. A report based on a three-year study by the National Council on Radiation Protection and Measurements claimed that contamination from such an attack would likely extend to several city blocks and that radiation would be "catastrophic but manageable." However, quite simple considerations show that such a bomb is merely a terror weapon without teeth; it would cause panic but it does not kill. And media stories actively promote such panic since the public fears anything that's even remotely connected with radioactivity.
     A dirty bomb makes no practical sense. To produce significant radioactivity over an area of, say, 1 square mile, the initial concentration within a small bomb would have to be roughly 10 million times greater and would quickly kill the terrorists trying to assemble the material. The radioactivity also creates large amounts of heat energy, sufficient to melt most containers. What's more, any such bomb would be easy to detect at long distance if it emits gamma rays. We therefore conclude that a dirty bomb is mostly hype.
     Similarly, damaging a nuclear reactor by impact or by sabotage is unrealistic. As compared to the World Trade Center towers, a reactor presents a very small target that is difficult to hit. Furthermore, it is protected by at least 3 feet of reinforced concrete, which even a large plane is unlikely to penetrate. On top of all that, it is easy to guard against impact with strategically placed steel towers or steel cables that would break up any aircraft. While they may not stop the plane's engines, the fuel will be spilled before the reactor is hit. The same kind of protection can be provided for the nearby storage of spent fuel, which is also enclosed with thick concrete.
     A ground attack is also unlikely to succeed. Even if terrorists could penetrate the normal security barriers, they would find that the control personnel had shut down the reactor. Turning it off can be done quickly. And even if a meltdown could be produced, the thick concrete containment structure prevents the escape of radioactivity into the environment. Chernobyl had no such containment.
     In the extremely unlikely event of a total reactor accident, the consequences are less severe than generally pictured. We have already seen the worst scenario that one can imagine: Even so, Chernobyl killed only some 30 people — those who were directly involved in putting out the fire. According to the International Atomic Energy Agency, the subsequent health effects have been minor: no increases in leukemia or birth defects; only cases of thyroid cancer that could have been avoided by taking protective potassium-iodide pills. Certainly, more people died from the panicky reaction to Chernobyl, including thousands of unnecessary abortions by women in Western Europe who feared the consequences from the release of radiation.
     We are left then with the only serious threat: nuclear bombs delivered by ships or even suitcases. But constructing and exploding a nuclear bomb is not a job for amateurs. It requires an infrastructure that can only be provided by a government.
     Even if the bomb is stolen, it must come from the arsenal of a known national government. The outstanding technical problems are detection of fissile material by remote sensing and establishing the provenance of the bomb for purpose of retaliation. Both are feasible and — I hope — being worked on. By announcing that we have, or are close to, solutions to these two problems we might achieve deterrence.
     In addition, we must have good intelligence and apply vigilance, diplomatic pressure, military threats of retaliation, and even pre-emption. But that's why we elect national leaders and invest in national defense.

     S. Fred Singer, a physicist, is emeritus professor of environmental sciences at the University of Virginia and a visiting Wesson Fellow at the Hoover Institution at Stanford University.