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Governments seeking to prevent a radiological terrorist attack face many obstacles.
Prevention of terrorists' use of a radiological weapon is extremely difficult because of the high number of radioactive sources around the world and the limited funds available with which to secure those sources.
Millions of radioactive sources are used every day for medical, industrial, research, and commercial purposes, all of which need to be adequately secured. Fortunately, however, only a small percentage of the sources are considered suitable for
making potent radiological weapons.
The following relatively common seven reactor-produced radioisotopes could pose particularly high security risks: americium-241, californium-252, cesium-137, cobalt-60, iridium-192, plutonium-238, and strontium-90. (See the
multimedia section for more information on each of these radioisotopes.) Sources containing appreciable amounts of these radioisotopes number in the tens of thousands around the world, and they must be adequately protected at every stage of their lifecycle—production, sale, transport, use, storage, and disposal. Ensuring that each of these sources is
safely and securely used will require time, money, and continued regulatory attention.
Adding to the difficulty in securing radioactive sources is that thousands of the sources have been lost, abandoned, stolen, or were never registered for government licenses. These sources are outside of government or institutional regulation and are called "orphan sources." In the United States alone, companies have reported losing track of almost 1,700 radioactive sources since 1998. Of the very large number of sources in use at any one time, an average of 430 sources are lost or stolen each year. Of these, approximately 60 percent are recovered. As with regulated sources, only a small percentage of orphan sources pose a high security risk; however, the large number of such sources indicates the need for better regulatory controls.
Why are there so many orphan sources? People looking to profit from the sale of the radioactive material or the shielding surrounding the material have stolen some sources. Thousands of orphaned radioactive sources remain in the former Soviet Union, left behind as the Russian Army returned to Russia after the end of the Cold War. Often, orphan sources are the result of too few proper disposal options for radioactive sources. In the United States, after a source has outlived its usefulness, the institution that was given the license to use and secure the radioactive source is responsible for its disposal. Sometimes, the source can be sent back to the original manufacturer, but this is not always possible if, for example, the manufacturer has gone out of business. Some used sources are sent to government-run regional disposal sites.
The United States has only three sites available for the disposal of unwanted sources with low levels of radioactivity (the Envirocare facility in Utah; the Barnwell facility in South Carolina; and the Hanford facility in Hanford, Washington), and none for highly radioactive sources (although Los Alamos National Laboratory has been accepting many of these sources on a temporary basis until a permanent repository is established). Furthermore, the Envirocare facility accepts only very low-level sources. The Hanford facility receives low-level waste only from the Rocky Mountain and Northwest Compacts. Until July 1, 2008, the Barnwell facility had accepted all types of low-level radioactive waste and was open to all states except those in the Rocky Mountain and Northwest Compacts. However, beginning on July 1, 2008, the Barnwell facility accepts waste only from the Atlantic Compact states of Connecticut, New Jersey, and South Carolina. Therefore, most states do not have access to a disposal site for most of their low-level waste. Even if the institutions seeking to dispose of radioactive waste—a costly procedure—can successfully access one of the waste sites, some institutions may find it easier and cheaper to simply abandon or improperly dispose of the source after it has outlived its usefulness.
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Transport container for radioactive
material recovered during an IAEA-assisted mission. |
Keeping track of radioactive sources can be even more difficult in developing countries. These countries may lack the money and the technical infrastructure and capabilities necessary to regulate the storage, use, and disposal of radioactive sources. A number of developing countries receive assistance from the IAEA, but countries that are not IAEA members are not eligible to receive this aid. In many developing nations, securing radioactive sources may not be considered a high priority. Even if security is considered important, facilities where radioactive materials are used may not be able to afford high-level security measures to protect the sources, and the government may not be able to provide a safe and secure disposal site. Costs of securing radioactive sources have continued to rise since the terrorist attacks of September 11, 2001. This has increased the difficulty of providing proper security for dangerous sources, even in highly industrialized countries such as the United States.
The difficulty in detecting radioactive sources presents a further challenge in preventing radiological terrorism. Most radioactive sources that present a security risk are considered dangerous not just because of their high radiation level, but also because of their mobility. The cobalt-60 radioactive sources used in food irradiation, for example, are only 12 inches long and one inch in diameter. The protective metallic shielding around the radioactive material can add to the weight of the source, but even heavier sources can be placed in cars or trucks for easy transport. And because it is virtually impossible to inspect every car, train, boat, and plane that exits and enters each country, radioactive sources are vulnerable to being smuggled across borders. More cities and border guards in North America, Europe, and Russia are learning how to check for increased radiation levels, but detecting radioactive sources will depend on proper training and equipment, alertness—and in many cases, luck.
Adding to the detection difficulty is that some countries that export radioactive sources do not have strict laws regulating these exports. The liberalization of commerce and export controls, easy access to information, and the internationalization of terrorist groups have increased the likelihood of terrorists using radiological weapons. The addition of nine nations, including some former Soviet states, to a passport-free European travel zone under the Schengen Agreement has increased concerns that radioactive materials could be more easily transported around the region.
However, the use of additional detection methods, such as infrared detectors or x-ray scanners, can increase the likelihood of detection. For instance, infrared detectors can measure the heat emitted from radioactive sources containing relatively large amounts of radioactive material. Also, x-ray scanners can indicate whether a package contains dense materials such as lead shielding for radioactive sources.
Detection of orphan sources is challenging, even when the existence and general location of the source is known. In June 2002, for example, a team of 80 international and Georgian experts spent two weeks on horseback, foot, and car searching a 550 square km area of western Georgia for two abandoned strontium-90 sources—but ultimately failed to find the sources.
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Members of the Georgian search team hunt
for orphan sources on former Soviet missile base near Tblisi. |
Other obstacles hamper efforts to prevent attacks on nuclear power plants. Most nuclear reactors are now equipped with back-up safety systems to prevent a meltdown of the nuclear core in case of an accident. But safety and security systems differ according to the country, the individual power plants, and the type of reactor. About half the commercial nuclear reactors in Russia, for example, are not protected by containment structures.
In addition, the safety and security measures originally put in place by power plant operators before the terrorist attacks of September 11th were not designed to prevent attacks by groups of suicidal terrorists using large commercial airplanes or multiple truck bombs. Governments and nuclear power plants are now in the process of reassessing security threats and improving their security measures.
Coming up with money to make these security improvements is another challenge in preventing radiological terrorism. Power plant operators must balance securing against possible threats with what the plant can realistically afford. The threat perception of the power plant operator will also determine what new security measures are to be provided. However, the plant operators must make sure that their plants provide enough security to meet the design-basis-threat (DBT). The DBT is intended to describe what security is required to defeat a credible threat to the plant.
Depending on the country, the particular location of the power plant, and the intelligence assessments provided to the authorities, plant operators may not foresee a terrorist attack or may not perceive much of a terrorist threat to their plants. Operators of a nuclear power plant located near a large city, for example, may sense more of a terrorist threat than those of a plant located in an isolated area. In addition, plant operators could be overwhelmed by an attack that exceeds the considerations of the DBT. For example, a terrorist attack may employ more attackers than foreseen in the DBT.
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Control room operators at the Fast Flux Test Facility in
Washington must pass comprehensive examinations
before being given the responsibility of overseeing the
operation of the reactor and support equipment |
Preventing attacks on nuclear power plants is even more difficult if the attack is carried out or assisted by an insider. Those who work inside the plant know the plant's physical layout and security measures. They are also more likely to know the less secured spots and the vital areas at that plant. Knowledge of these details greatly increases the probability of a successful terrorist attack. This is why the United States requires that nuclear power plant employees undergo a criminal background check and a psychiatric test. Unfortunately, judging future intentions and actions of each employee is an impossible task. Thus, these precautions do not completely rule out the insider terrorist threat.
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