Nuclear Terrorism Expert Answers Viewers' Questions

In response to ABC News' investigative series on the threat of a nuclear attack, some viewers had questions about the nation's preparedness and what to do in the event of an attack.

Below are answers to some of the questions from nuclear terrorism expert Graham T. Allison. Allison is a professor of government at Harvard University and the director of the Belfer Center for Science and International Affairs. During the first term of the Clinton administration, Allison served as assistant secretary of defense for Policy and Plans, where he coordinated Department of Defense strategy and policy toward states of the former Soviet Union.

Question 1. Kim asks: Why would you do a report that includes information to help terrorists find the "holes" in our nuclear waste security? I believe it is dangerous, if not poor journalism, to do this. I realize that you are trying to make all aware of the dangers; however, I believe you could have done this without showing on video the "holes" for terrorists to see.

John says: I find it very disturbing that you would take it upon yourselves to broadcast the shortcomings our country's security concerning nuclear weapons. This should have been an issue between you and the government, going public should have been a last-ditch effort after all else has failed.

Answer: The troubling question is whether such reports could give terrorists ideas and clues for attacks. The nightmare for everyone in the national security debate is that communication aimed at awakening fellow Americans to risks inadvertently inspires or informs murderers.

The media has struggled to strike the right balance. In this case, ABC went the extra mile and offered U.S. government officials an opportunity to review its videotapes before going public -- not to allow censorship of its reports, but rather to give authorities a chance to correct vulnerabilities prior to broadcast. Most declined.

To his credit, the head of Nuclear Security for the Nuclear Regulatory Commission not only reviewed the tapes but acted upon them, ordering immediate changes at sites that posed the greatest danger.

Question 2. CWS writes: The manner in which you have positioned this story and the "Loose Nukes" series sounds like this is inevitable, as if it will happen within the next few weeks. Are you trying to scare the public? Do you have information that needs to be shared? Why is this story coming out now? This is truly a terrifying scenario. What would be the U.S. response to such an attack?

Answer: The threat of loose nuclear materials from Russia, and al Qaeda's expressed interest in obtaining nuclear weapons has been a deep concern for national security experts for 15 years.

The U.S. response would depend on several factors: How many Americans were killed, whether the U.S. could identify the culprits behind the attack, and whether nuclear scientists could identify the source of the fissile material used to make the bomb to a foreign government. But after such a catastrophe, our government would have no good options -- only bad and worse. Thus, the premium is on prevention now.

Question 3. Howard in California asks: The advent of a terrorist sponsored nuclear attack, I believe, is an obsessive and imminent objective of al Qaeda. Why haven't I heard anything from my state and local governments on their preparedness and procedures that I should know about both before and after the event?

Answer: As a citizen, you should be pressing your state and local elected officials for answers to your important questions.

Question 4. Eugenia writes: How will we know where we are supposed to evacuate to if a nuclear blast were to occur? Is this something we can prepare for in advance?

Answer: For information on how to prepare for a range of terrorist attacks, visit the Red Cross:, or the Department of Homeland Security:

Question 5. Joel asks: Has the U.S. inventory of current and spent nuclear materials been accounted for in full?

Answer: To the best of our knowledge, the entire U.S. inventory of nuclear materials has been accounted for.

Question 6. Ed asks: It has been reported that there are suitcase nukes from the Russian Cold War days missing from their inventory and that they may be already in the United States to be used by terrorists. Can they still be used? If this were true, what would the average Joe do to prepare for such an event? What do I tell my daughter who is going to school in the city of Tampa, Fla., where such an event would be very likely to occur with McDill (Southern Command) being in the blast zone.

Answer: In 1997, General Alexander Lebed, Boris Yeltsin's national security advisor, acknowledged to CBS News' "60 Minutes" that 84 of 132 KGB "suitcase" nuclear weapons were not accounted for in Russia. Lebed later recanted his statement. The Russian line has remained that no such weapons were made and that all their nuclear materials are secure. The bottom line is that it is likely Russia made small-yield nuclear weapons that could be carried by one person, and that we cannot say with any certainty that such weapons did not go missing.

If a suitcase nuclear weapon were stolen it might have locks and environmental sensing devices, which nuclear thieves could likely overcome in a few days. It is possible that the weapon would fail to detonate because it would not have been serviced recently. Terrorists could still cannibalize the weapon for the fissile material with which they could make a crude nuclear bomb.

Question 7. Richard writes: Hello Graham -- Having been born on 8/6/45, I have a more than passing interest on the subject of nukes. I have read articles by certain scientists minimizing the danger of a so-called "dirty bomb," stating that in fact the danger is primarily psychological rather than physical. What is your opinion?

Answer: I agree. Experts call dirty bombs a weapon of mass disruption. Those who die from dirty bomb will be killed by the bomb, e.g. the dynamite, not the radioactivity. For more specifics, see the FAQs at

Question 8. Kevin asks: In the ABC News coverage this week, there is advice that in case one is near a nuclear blast you should turn on your radio or TV and drive away in a car. Wouldn't such a blast generate an "EMP" (electromagnetic pulse) that would render broadcast receivers and motor vehicles useless?

Answer: A large nuclear detonation in the atmosphere could cause widespread damage to all electronic components nearby. A nuclear terror attack, however, would likely be smaller in terms of destructive power and on the ground. While it could "fry" local radio and cell-phone towers, its damage to electronic components would likely be more localized.

Question 9. Bill asks: What cities appear to be prime targets and why? Is it population density, military communities nearby, financial districts, proximity to international borders or the shock effect of hitting a major population center? Or could it be a combination of all of these that might make a city an attractive target to terrorists?

Answer: Based on their actions and statements, we can assume that al Qaeda would want to attack cities that have high-density populations, vulnerable financial centers, and symbolic targets. Communities that al Qaeda operatives have discussed targeting with terrorist attacks include: New York City, New Jersey financial areas, Washington, D.C., Los Angeles, and San Francisco, among others.

Question 10. Mahala asks: If I have to shelter in my basement during a nuclear attack, what is the best way to prepare this space? I am concerned about clean air and keeping radiation at as minimum a level as possible. Short of building a bomb shelter, what can I do?

Answer: See my answer to question four.

Question 11. Sandra asks: Why hasn't the nuclear waste been moved to safer locations, like Yucca Mountain? Yucca isn't perfect, but it's a lot better than tents and glorified swimming pools where most of the waste is now. Yucca's more defensible, and it's safer from floods and fires (ask Los Alamos about the plutonium that got loose after the last big fire!) than most of the current storage sites. Will it take a disaster to move the nuclear waste to safer repositories?

Answer: Finding a permanent and secure resting place for spent nuclear fuel would go a long way to safeguarding communities surrounding nuclear reactors, and deny terrorists the radioactive materials from which to make a dirty bomb.