How Nuclear Detectives Work

If you've spent much time in a movie theater, you've probably witnessed an armed standoff. The participants in these scenes range from gun-slinging cowboys to killer androids, but the scenario is typically the same: Two or more opposing forces draw their guns at the same time, resulting in a stalemate. If one side shoots, the other side shoots -- and everyone goes down in a hail of bullets. This is generally the point in the movie where dialogue takes center stage.

In movie standoffs, the desired outcome is that everyone slowly puts his or her weapon away and some sort of truce prevails. The same holds true for nuclear arms proliferation as well, thanks to the notion of mutual assured destruction. This boils down to one simple idea: "If you nuke me, I'll nuke you, and neither of us will come out ahead." It's a delicate situation, but one that can be reasoned through. In fact, in 1970, 190 nations signed the Treaty on the Non-Proliferation of Nuclear Weapons (NPT), an effort to not only convince everyone to lower their weapons, but to steadily disarm as well.

But if you've watched enough cinematic gun-pointing, you know a tentative stalemate can easily spiral into chaos when someone else suddenly enters the room. Similarly, it's essential to nuclear disarmament that no one else suddenly enters the standoff.

To help in this matter, the United Nations charged the International Atomic Energy Agency (IAEA) with the task of defining and inspecting safeguards to promote the peaceful use of atomic energy, while also making sure nations don't pursue the development of nuclear weapons. Government officials aren't always that forthcoming about secret nuclear programs, and military intelligence sometimes misses the mark on finding weapons of mass destruction. After all, you can scrutinize satellite imagery and track the transportation of raw materials all you want, but the best proof inevitably comes from on-site analysis.

Nuclear materials emit radiation and are easy to identity at close range with the right equipment. In some cases, intelligence agencies can sneak detection devices into an area to follow up on suspicions, but this isn't always an option. The IAEA takes a more direct, legalistic approach, using international pressure to gain a country's permission to tour facilities in such countries like Iran, Iraq and North Korea. The IAEA depends on U.N. mandates and willing cooperation to perform inspections, and this factor has worked against the agency in the past. For instance, North Korea expelled IAEA inspectors from the country in 2002, and in 2007, Iran refused to allow IAEA personnel unlimited access to its nuclear facilities [source: BBC].

But in the best of scenarios, the agency is able to provide concrete evidence for U.N. nations to use in confronting countries suspected of developing nuclear weap­ons. For instance, in 2003, the IAEA was able to confront both Libya and Iran with evidence of military-oriented nuclear activity. As a result, Libya abandoned its nuclear program, and Iran gave up the identities of suppliers in Pakistan [source: The Economist].

The nuclear detectives themselves range greatly in age and nationality. While they boast backgrounds ranging from scientific research to hands-on military weapons experience, all inspectors undergo extensive training prior to deployment.

­The IAEA was awarded the Nobel Peace Prize in 2005 for its efforts, despite withstanding criticism over the years from both sides. Nations under investigation have accused the organization of attempting to keep beneficial nuclear technology out of the hands of developing nations. Meanwhile, the United States has charged the group with being too lenient on such nations.

When dealing with national nuclear weapons programs, the key players are generally intelligence organizations, politicians and the International Atomic Energy Agency (IAEA). And while nations and their leaders can prove difficult to negotiate with at times, other potential nuclear threats are far more elusive. How do you impose sanctions against a terrorist organization? Who inspects the warehouses of an illegal smuggling cartel?

­When it comes to the trafficking of radioactive materials, it's easy to underestimate the problem. After all, the plots of most TV shows, movies and video games revolve around the actions of a single smuggling or terrorism operation. How many black-market dealers could there be in the world, right?

The answer to that question may terrify you. According to the IAEA Illicit Trafficking Database, there were a reported 252 incidents of unauthorized acquisition, provision, possession, use, transfer or disposal of nuclear or radioactive materials -- and that's just the total for 2006. Between 1993 and 2006, a total of 1,080 incidents were reported [source: IAEA]. The materials ranged from radioactive medical materials to quantities of enriched uranium. To learn more about these alarming crimes, read How easy is it to steal a nuclear bomb?

Various military, law enforcement and intelligence agencies work together to intercept these items, using everything from high-tech radiation detection equipment to old-fashioned detective work. Confiscating the materials is just the first step. Traditional investigation practices might allow authorities to track down the intended recipient -- and even trace the materials back to their source. Nuclear forensics, however, allows detectives to follow clues inside the materials themselves.

For instance, if investigators examine the isotopes and impurities in a sample of uranium, they can actually tell where it was mined and how it was processed. There's a finite number of places in the world either could have taken place. Plutonium, on the other hand, has to undergo enrichment in a particle reactor, and careful analysis at a nuclear laboratory can pinpoint exactly what kind of reactor was used. Once detectives know where the materials originated, they can focus their investigation on how they were leaked or stolen to begin with.

­But what happens if preemptive efforts fail? How can nuclear forensics help in the wake of an actual nuclear attack?

From international organizations to local police forces, a lot of time and effort goes into preventing nuclear or radioactive materials from falling into the hands of terrorist organizations. But should the worst come to pass and either a nuclear device or a radioactive dirty bomb detonate, nuclear detectives would play a vital role in determining the nature of the incident and narrowing down its possible origins. In this respect, the investigation would resemble a traditional crime scene investigation, asking what the murder weapon was, where it came from and who the perpetrator might have been.

­Nuclear forensics specialists would first have to determine whether the attack involved radioactive materials. If so, the next step would be to determine whether uranium or plutonium was used and how sophisticated the device was. By studying trace materials left over from the explosion, scientists would be able to study the isotopes and impurities in a sample of uranium or the enrichment level of plutonium to home in on its origins. The presence of high-energy neutrons or tritium would signify that the device was thermonuclear in nature. By comparing the blast site to recorded nuclear weapons tests, investigators could further narrow in on the device design used.

The actual groups responsible for investigating such incidents varies from country to country. In the United States, domestic nuclear forensics experts would turn over all information to the FBI. Other countries or international groups such as the IAEA would only become involved if asked to participate.

But not every event would necessarily transpire on an epic scale. For instance, nuclear forensics played a role in helping British authorities investigate the 2006 death of writer Alexander Litvinenko in London. The former KGB agent became sick following lunch with Russian Andrei Lugovoi. Three weeks later, Litvinenko died of radiation poisoning due to significant amounts of polonium-210 in his system. Investigators were able to follow a trail of polonium-210 back to a hotel room Lugovoi occupied in the weeks leading up to the meeting [source: BBC].

The Litvinenko case stands out as a rare case of suspected homicide by radiation poisoning. But the case also underlines that, despite all the security measures in place, individuals can acquire radioactive materials and use them as a weapon. Some advocates argue that more funding should go to promote the study of nuclear forensics, so as to better prepare the world for possible attacks in the future.

­Explore the links on the next page to learn more about radiation, forensics and nuclear weapons.