Nuclear Power Plants, Security
Nuclear Power Plants, Security
█ LARRY GILMAN
Nuclear power plants pose two basic security concerns. First, all nuclear reactors both use and produce radioactive elements (e.g., uranium and plutonium) that can be used to build nuclear weapons. Second, all reactors and nuclear-waste storage facilities contain large amounts of radioactive material. This material might be stolen for later use as a terrorist weapon (e.g., by being combined with conventional explosives to form a radiological dispersal weapon, also termed a "dirty bomb") or, in the case of concentrated fuel, to build nuclear weapons. Alternatively, radioactivity might be released directly to the environment by sabotaging safety systems or blowing up a facility with missiles, planted charges, or hijacked jet aircraft. Thus, nuclear facilities on a nation's own territory threaten its security as a target of enemy action, while nuclear facilities on an enemy's territory threaten security as a possible source of nuclear weapons.
Nuclear proliferation, as the possession of nuclear weapons by ever-greater numbers of nations is termed, has been a recognized global hazard since at least the 1960s. In contrast, the possibility that nuclear facilities on one's own territory might be employed by an enemy as ready-made weapons has been of greatly heightened public concern since the terror attacks of September 11,2001. Both threats are serious and plausible. Even a relatively small nuclear weapon of the size that destroyed the city of Hiroshima on August 9, 1945, could kill hundreds of thousands of people, and such a bomb requires only
about 15 lb (7 kg) of uranium-235 (U235) or a similar quantity of plutonium. Every large (i.e., 100-MW range) nuclear power plant contains hundreds of pounds of both these substances and produces hundreds of additional pounds of plutonium every year. Meanwhile, release of a significant fraction of the radioactive material in any large nuclear reactor, reprocessing plant, or waste-storage facility could cause an unpredictable number of deaths over a continent-sized area and make thousands of square miles of land uninhabitable for time periods ranging from days to centuries.
Reactor fuel and bomb material. Both nuclear reactors and fission-type nuclear weapons exploit the fact that atoms of some elements (e.g., uranium and plutonium) are unstable, that is, their nuclei have a natural tendency to break apart. When a nucleus breaks apart (fissions), it releases smaller nuclei, electrons, high-energy photons, and fast-moving neutrons. If one of these neutrons strikes another unstable nucleus, that nucleus may also fission, releasing still more neutrons, which may trigger still other nuclei, and so on and so on in a self-sustaining chain reaction. This chain reaction is the energy source of both reactors and fission bombs, the main difference being that in a reactor the chain reaction proceeds at approximately constant speed, while in a bomb, it spreads at geometrically increasing speeds.
Reactor fuel—the mixture of radioactive metals used to sustain a chain reaction in the core of a typical electricity-generating reactor—is only 3–5 percent U235, the rest being mostly uranium-238 (U238), a comparatively stable form of uranium. This means that a nuclear bomb cannot be made directly out of ordinary commercial reactor fuel. However, "research" reactors, most of which produce radioisotopes for medical and industrial purposes, run on nearly pure U235, the same material used to destroy Hiroshima. There are about 550 such reactors in the world, several of which—including Israel's reactor at Dimona—have actually been used to produce nuclear weapons clandestinely. Furthermore, during the ordinary process of "burning" reactor fuel some of its U238 is changed by neutron bombardment to plutonium-239 (Pu239). This can be extracted from the spent fuel, concentrated, and used either as reactor fuel or to build bombs.
Western intelligence sources assume that India, Israel, Pakistan, South Africa, and (probably) North Korea have built nuclear weapons using U235 or Pu239 obtained from reactor programs publicly dedicated to research or electrical power generation. Other nations will probably do so in the future.
Security and proliferation. For many years, as part of the Atoms for Peace program initiated by President Eisenhower in 1953, the United States literally gave away reactors, nuclear materials, and essential nuclear knowledge to many countries. At least 26 reactors fueled by highlyenriched (bomb-grade) uranium were given to countries including Argentina, Brazil, Iran, Israel, South Korea, Pakistan, Spain, and Taiwan. Thousands of scientists from these countries and others were trained in reactor theory, plutonium extraction and enrichment, and other knowledge essential to nuclear bomb manufacture. Thanks to Atoms for Peace (and sales of nuclear technologies by other nuclear powers), preventing the global proliferation of nuclear weapons by restricting nuclear materials, reactors, and reprocessing facilities to a relatively few states ceased to be an option long ago. Nuclear proliferation has occurred and will probably continue. Israel is now believed by most observers to possess more than 200 nuclear weapons, India exploded its first nuclear weapon in 1974, and Pakistan (whose first nuclear reactor was a gift from the U.S.) exploded its first nuclear weapon in 1998.
Systematic efforts, however, have been made to control the proliferation of nuclear weapons worldwide. The International Atomic Energy Agency (IAEA) is an arm of the United Nations charged with the promotion and global monitoring of nuclear power. The IAEA has sought, through inspections programs, to prevent the diversion of nuclear materials from reactors to weapons. Compliance with IAEA inspections is, however, voluntary. Furthermore, diversions below the "measurement noise level" could suffice to build a nuclear weapon. For example, in a nuclear facility where 1,000 1-kilogram units of fissionable material were measured to an accuracy of .001 kilogram each year, up to 1 kilogram (1,000 samples of less than.001 kg each) could be undetectably diverted annually, and enough for a bomb accumulated in a few years. Many observers deem it unlikely that any state seriously desiring to manufacture nuclear weapons has yet been prevented from doing so by IAEA inspections.
Another method for controlling proliferation, so far adopted only by Iran and Israel, is the destruction of nuclear facilities possessed by enemy states. On September 30, 1980, planes bearing Iranian markings destroyed Iraq's Tuwaitha nuclear research center near Baghdad, the capital of Iraq. On June 7, 1981, 16 Israeli aircraft destroyed the Osirak "research" reactor just south of Baghdad. Israel had tried to prevent completion of the French-supplied facility by means of threatening letters, sabotage, and assassination, but had failed. (The June 7 air attack demolished the facility before it was fueled and operational, so no life-threatening release of radiation occurred.) These attacks may have been effective in their goal of preventing Iraq from obtaining nuclear weapons. However, it is not practical to prevent nuclear proliferation by these means on a global scale.
Thus there does not seem to be any long-term, sure-fire method of preventing technically sophisticated countries that possess nuclear reactors from exploiting them to build nuclear weapons if they so desire. If this is true, absolute security from nuclear weapons is a chimerical goal, and the best that can be hoped for is ongoing negotiation for a state of permanent, radical, and global in security.
Protecting nuclear facilities. Many radioactive elements besides Pu239 accumulate in reactor fuel as it is irradiated in a reactor core. The fast-moving particles and high-energy photons emitted by these elements can kill living things either directly or by causing genetic damage; spent reactor fuel and materials derived from it are, therefore, dangerous to approach or ingest. Furthermore, they will remain so for periods of time greatly exceeding the duration of human history thus far; Pu239, for example, has a half-life of approximately 24,000 years (i.e., only half the atoms in any sample of Pu239 will have fissioned after 24,000 years).
Material radioactive enough to be classified as high-level waste is produced continuously by operating nuclear reactors and by facilities that reprocess spent fuel to extract plutonium. For example, the fuel in a typical electricity-generating reactor (of which 104 are operating in the United States) must be swapped out for fresh fuel every few years. The best long-term hope for disposing of this spent fuel is deep burial in rocks that seem likely to remain stable for hundreds of thousands of years. However, in most of the world, including the United States, no deep-burial program yet exists, so all high-level waste is stored on the surface in containers, usually on the grounds of the nuclear plants that produce it. Release to the environment of the material in even one such repository would be a highly effective act of terrorism.
Persons wishing to attack a nuclear reactor or other nuclear facility have a wide range of options. They may seek to intercept or sabotage shipments of fuel or waste; invade a facility using armed force or deception, then proceed to steal radioactive material, blow up the facility, or (if it is a reactor) cause it to melt down; or seek to breach the containments of reactors or waste-storage facilities using truck bombs, missiles, hijacked aircraft, or other means. All facilities containing significant amounts of radioactive material must therefore be defended from a wide range of possible attacks.
Reactor and waste-storage security has been based for decades on a concept termed "defense in depth." The defense-in-depth method requires that each nuclear facility be surrounded by concentric security barriers. The outermost barrier is invariably a high fence topped with razorwire. The grounds near the fence, inside and out, are monitored by intruder-detection devices, and vehicles can only enter through checkpoints staffed by armed guards. Thirty to 40 guards are on duty at all times at a typical nuclear power plant, and vehicle gates, doors, and the like remain locked.
Defense in depth seeks to provide security against an imaginary scenario termed the Design Basis Threat, which is defined by the U.S. Nuclear Regulatory Commission (NRC). Prior to September 11, 2001, the Design Basis Threat included a truck bomb the size of that used to attack the World Trade Center in 1993, three outside attackers, and one collaborator inside the plant. Also, the NRC stated in its public-relations material that there was no credible security threat to the nation's nuclear facilities. The NRC removed these statements from the Web along with the rest of its website shortly after the September attacks, wishing to "review posted material to make sure there was no sensitive information that could be misused to harm the security of our nation" (http://www.nrc.gov/what-we-do/safeguards/response-911.html).
However, among some scientists, there had long been skepticism about the adequacy of defense in depth and the Design Basis Threat. From the 1970s until 2001, the NRC staged mock attacks (termed Operational Safeguard Response Evaluations) to test plant security. Forty-six percent of plants tested from the 1970s until 1998 failed evaluation; from 1998 to September 11, 2001, 9 out of 11 plants tested failed; no evaluations have been conducted since. Furthermore, doubts linger about the ability of plant personnel to defend against determined attack. Most of the guards who are supposed to be able to repel a determined (perhaps suicidal) paramilitary or terrorist assault are actually hired from private security companies, in some cases paid less than janitors working at the same facilities. In the wake of the September 11, 2001 attacks, state troopers and National Guard troops have been deployed to assist these personnel in guarding nuclear plants against attack; however, in response to NRC orders to increase security, some are now working extraordinarily long hours, and further supplemental plans are under review.
The terrorist attacks of September 2001 have given official credibility to the use of wide-body civilian aircraft as weapons. However, no nuclear facility has been specifically designed to withstand such an attack. The NRC states that "previously…[it] had no reason to perform a detailed engineering analysis of the consequences of a deliberate attack on nuclear facilities by a large airliner," yet the idea of targeting reactors with jumbo jets was being pointed out over twenty years ago by critics who recalled the Christmas Day, 1974, hijacking of a jumbo jet by a man who threatened to crash it into the center of Rome. (The man was overpowered after making his threat.) It is likely that such extreme threats to nuclear-facility security were not considered prior to September 11 not because nobody had thought of them but because (a) they were thought to be highly improbable, and (b) the cost of rendering facilities attack-proof against them (e.g., by building them underground) would have made nuclear power too expensive to develop for civilian markets.
The NRC states that it is now analyzing the consequences of a aerial attack on a nuclear power plant and plans to upgrade its Design Basis Threat to include as many attackers as were involved in the attacks of September 2001. It is not known whether the new NRC standard, when announced, will include provisions for defending plants against jumbo jets used as weapons, either by shooting them down or hardening reactor facilities against massive impact and fire. It is also not known what security precautions the NRC will mandate for in-transit nuclear waste if the federally-owned deep-storage facility at Yucca Mountain, Nevada, begins to receive high-level waste shipments from around the country in 2010 as planned.
As of July 2002, at least 16 states had taken the precaution of requesting stockpiles of potassium iodide pills from the NRC. All persons, especially children, are vulnerable to thyroid cancer caused by even small quantities of radioactive iodine, a substance expected to be a major component of the fallout from any nuclear incident. If ingested in a timely way, potassium iodide saturates the thyroid gland with non-radioactive iodine and prevents it from absorbing lethal levels of radioactive isotopes.
Conclusion. The security of nuclear facilities of all kinds is under more intense scrutiny—both by defenders and by potential attackers—than ever before, and not only in the United States. Old security standards are now admitted to have been inadequate, but enhanced standards have not yet been officially defined and uniformly implemented.
The goal of security—both from nuclear weapons derived from power plants and other "peaceful" facilities, and from takeover of nuclear facilities by groups of well-armed attackers—remains urgent, but elusive. In January 2002, President George W. Bush announced that "diagrams of nuclear power plants" had been found among items captured from terrorist groups in Afghanistan.
█ FURTHER READING:
Lovins, Amory B., and L. Hunter Lovins. Brittle Power: Energy Strategy for National Security. Andover, MA: Brick House Publishing, 1982.
Ramberg, Bennett. Nuclear Power Plants as Weapons for the Enemy: An Unrecognized Military Peril. Berkeley, CA: University of California Press, 1984.
Wald, Matthew L. "Guards at Nuclear Plants Say They Feel Swamped by a Deluge of Overtime." New York Times. October 20, 2002.
"States Mull Anti-Cancer Pill in Response to Terrorist Attack." National Council of State Legislatures. July, 2002. <http://www.ncsl.org/programs/health/anticancerpills.htm> (December 11, 2002).
"Nuclear Security—Before and After September 11." U.S. Nuclear Regulatory Commission. September 23, 2002. <http://www.nrc.gov/what-we-do/safeguards/response-911.html> (December 11, 2002).
Nuclear Regulatory Commission (NRC), United States
Weapon-Grade Plutonium and Uranium, Tracking Nuclear Proliferation.