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July 8, 2008

Exclusive: An Introduction to Nuclear Technology

Tom Ordeman, Jr.

The mid-1940s ushered the world into the nuclear age. Just as so many technological developments have become both thrilling successes and horrible liabilities, the nuclear age has had a bittersweet history. The use of two nuclear weapons to end World War II, coupled with a handful of high profile safety incidents at nuclear energy stations, has led many to question the viability of this technology. However, because the workings of both nuclear weapons and nuclear energy are somewhat complex, both sides of the nuclear coin are often misunderstood by the average individual. In point of fact, these technologies are not difficult to understand at a base level.

When the word "nuclear" is used, it refers to a reaction within the nucleus of an atom. There are two types of nuclear reactions, and they are polar opposites of one another: nuclear fusion, and nuclear fission. A fusion reaction involves additional particles bonding to an atom's nucleus, while a fission reaction involves splitting an atom's nucleus into multiple pieces. These types of reactions release energy, and both fusion and fission reactions have both military and civil applications.

Scientists continue to develop methods of inciting nuclear fusion. The fusion process takes a great deal of energy, and only in the last few years have researchers been able to develop fusion reactors that are able to produce slightly more energy than they consume. A consortium of countries including the United States, the European Union, the Russian Federation, India, Japan, the Republic of Korea, and the People's Republic of China are participating in the ITER project, the purpose of which is to design and build a revolutionary fusion research reactor in Cadarache, France. Fusion energy has a great deal of potential, but as it is still in the experimental phase, this series will deal almost exclusively with nuclear fission.

Nuclear fission involves the use of isotopes. Chemical elements are considered to be stable when they have a particular atomic weight, which takes its total number of particles into account. When an atom's atomic weight differs from its natural atomic weight (as appears on the Periodic Table), that atom is called an isotope. Isotopes are unstable by nature, and are naturally predisposed to returning to their natural atomic weight. Nuclear fission capitalizes on this by arranging atoms in temporarily stable configurations, then destabilizing them by adding additional isotopes in order to trigger a reaction. When additional particles are introduced, the atom becomes unstable to the point of splitting, a process that releases energy. This energy can be harnessed in either a nuclear reactor, or a nuclear weapon.

The nuclear process requires fissile material, and the most commonly used fissile element is Uranium. Naturally-occurring Uranium is Uranium-235. U-235 is slightly radioactive. In order to be useful, Uranium must first undergo a refining process. This turns it into yellowcake, a coarse powder that can be used for two processes: energy generation through certain types of reactors, or enrichment for use with other types of reactors. Continued enrichment of yellowcake or enriched uranium produces highly enriched uranium, the ingredient necessary for the creation of uranium-based nuclear weapons.

Uranium enrichment involves refining uranium in order to make it pure enough to support a nuclear reaction. For a nuclear reactor, nuclear fuel rods must contain between two and three percent U-235 atoms in order to sustain a nuclear reaction. or weapons-grade uranium, the amount of U-235 atoms must exceed 90% in order to sustain the type of reaction needed for a nuclear explosion. The higher the proportion of U-235 atoms, the quicker the nuclear reaction occurs. While nuclear reactors need only create a limited amount of energy for the purpose of heating water for the purpose of driving a turbine, a nuclear weapon must create a much quicker reaction in order to create the heat and energy needed for a nuclear explosion.

While both civil reactors and nuclear weapons involve a fission reaction, and while both involve the controlled use of radiation for their purposes, the actual reactions are very different. A common misconception is that an accident at a nuclear energy station would be the equivalent of setting off a nuclear weapon. This is not the case. Most of the risk associated with a nuclear reactor stems from the use of pressurized systems, which must be strictly maintained in order to prevent the release of non-radioactive pressurized steam. While radiation leakage must be prevented, the threat of a massive weapons-level explosion in a nuclear reactor is unrealistic.

The next installment will discuss the uranium enrichment process, and the basic anatomy of a nuclear reactor.

Family Security Matters Contributing Editor Tom Ordeman, Jr. is a technical writer for a major defense contractor in Hampton Roads, Virginia. Feedback: editorialdirector@familysecuritymatters.org.

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