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Science and Society

High-Level Nuclear Waste
n 1982, the U.S. Congress established a This was based on data collected for nearly The current Administration has deter-
Inational policy to solve the problem of 10 years. The nine sites were studied, and mined that Yucca Mountain is not a work-
nuclear waste disposal. This policy is a fed- results of these preliminary studies were able option for a long-term repository for
eral law called the Nuclear Waste Policy Act. reported in 1985. Based on these reports, spent nuclear fuel and high-level radio-
Congress based this policy on what most President Ronald Reagan approved three active waste. Accordingly, on February 1,
scientists worldwide agreed is the best way sites for intensive scientific study called 2010, DOE filed a motion with the Nuclear
to dispose of nuclear waste. site characterization. The three sites were Regulatory Commission to stay the pend-
The Nuclear Waste Policy Act made the Handford, Washington; Deaf Smith County, ing proceedings on DOE’s Yucca Mountain
U.S. Department of Energy responsible for Texas; and Yucca Mountain, Nevada. repository license application filed June
finding a site, building, and operating an In 1987, Congress amended the Nuclear 2008 until DOE’s planned motion to with-
underground disposal facility called a geo- Waste Policy Act and directed the Energy draw is resolved. The motion to stay the
logic respository. Department to study only Yucca Mountain. proceedings was granted on February 16,
In 1983, the Energy Department On July 9, 2002, the U.S. Senate cast the final 2010. On March 3, 2010, DOE filed a
selected nine locations in six states for con- legislative vote approving the development motion to withdraw the license application
sideration as potential respository sites. of a repository at Yucca Mountain. with prejudice.*

*Press Release: www.energy.gov/news/8721.htm

requires an increased density, and a longer confinement time the original reactant nucleus. When massive nuclei undergo
requires less density. The primary problems of fusion research are fission, much energy is rapidly released along with fission
the high-temperature requirements and confinement. No mate- products that continue to release energy through radioactive
rial in the world can stand up to a temperature of 100 million°C, decay. What is the source of all this nuclear energy? The answer
and any material container would be instantly vaporized. Thus, to this question is found in current theories about how the uni-
research has centered on meeting the fusion reaction require- verse started and in theories about the life cycle of the stars.
ments without a material container. Two approaches are being Theories about the life cycle of stars are discussed in chapters 14
tested: magnetic confinement and inertial confinement. and 15. For now, consider just a brief introduction to the life
Magnetic confinement utilizes a very hot plasma, a gas cycle of a star in order to understand the ultimate source of
consisting of atoms that have been stripped of their electrons nuclear energy.
because of the high kinetic energies. The resulting positively and The current universe is believed to have started with a
negatively charged particles respond to electrical and magnetic “big bang” of energy, which created a plasma of protons and
forces, enabling researchers to develop a “magnetic bottle,” that neutrons. This primordial plasma cooled rapidly and, after
is, magnetic fields that confine the plasma and avoid the prob- several minutes, began to form hydrogen nuclei. Throughout
lems of material containers that would vaporize. A magnetically the newly formed universe, massive numbers of hydrogen
57
confined plasma is very unstable, however, and researchers have atoms—on the order of 10 nuclei—were gradually pulled
compared the problem to trying to carry a block of jello on a together by gravity into masses that would become the stars.
pair of rubber bands. Different magnetic field geometries and As the hydrogen atoms fell toward the center of each mass of
magnetic “mirrors” are the topics of research in attempts to sta- gas, they accelerated, just as any other falling object. As they
bilize the hot, wobbly plasma. Electric currents, injection of fast accelerated, the contracting mass began to heat up because
ions, and radio-frequency (microwave) heating methods are also the average kinetic energy of the atoms increased from accel-
being studied. eration. Eventually, after, say, 10 million years or so of collaps-
Inertial confinement is an attempt to heat and compress ing and heating, the mass of hydrogen condensed to a sphere
small frozen pellets of deuterium and tritium with ener- with a diameter of 1.5 million miles or so, or about twice the
getic laser beams or particle beams, producing fusion. The size of the Sun today. At the same time, the interior temper-
focus of this research is new and powerful lasers, light ion ature increased to millions of degrees, reaching the critical
and heavy ion beams. If successful, magnetic or inertial con- points of density, temperature, and containment for a fusion
finement will provide a long-term solution for future energy reaction to begin. Thus, a star was born as hydrogen nuclei
requirements. fused into helium nuclei, releasing enough energy that the
star began to shine.
Hydrogen nuclei in the newborn star had a higher energy
THE SOURCE OF NUCLEAR ENERGY per nucleon than helium nuclei, and helium nuclei had more
When elements undergo the natural radioactive decay process, energy per nucleon than other nuclei up to around iron. The
energy is released, and the decay products have less energy than fusion process continued for billions of years, releasing energy

13-23 CHAPTER 13 Nuclear Reactions 345