With constant reminders of the tenuous state of energy production and the limited nature of the fuel resources that are commonly exploited for that purpose, it should be clear to almost all of us that drastic changes involving our energy sources and methods of production are required in order to sustain our worldwide culture and society into the future. One of the alternatives that are now coming to light is the Laser Inertial Fusion-Fission Energy (L.I.F.E.) program that is now being developed at the National Ignition Facility found at the Lawrence Livermore National Laboratory in California. This research has the potential to greatly modify the landscape of both our social and scientific worldviews while providing a safe, clean, and efficient source of electricity fueled by a resource that is both abundant and not likely to become exhausted at any time in the foreseeable future. In the following pages I hope to provide a brief overview of the history and explanation of the processes involved, the program that is being developed at the National Ignition Facility, and the potential benefits that can be derived from the work that is being done.
Definitions and Relevant History:
The following paragraphs provide a basic working understanding of the process of nuclear fusion as well as a very brief overview of the relevant steps that have led to the development of the program housed at the National Ignition Facility.
In the 2008 report “Fusion as an Energy Source: Challenges and Opportunities” by W.J. Nuttall, fusion is defined as the formation of a stable atomic nucleus through the combination (fusing) of less stable, smaller atomic nuclei. The energy derived from a nuclear fusion reaction comes from the “difference between the nuclear binding energies of the initial and final components.” In the sun, fusion takes place at temperatures at around 15 million°C, whereas those in experimental reactors are closer to 100 million°C. A part of the reason for the greater temperature requirements for the fusion reactions that take place in laboratory environments here on earth as opposed to those that take place in stars is that the pressure and the mass of fuel involved is far greater in a star, and thus greater temperatures are required to produce similar reactions on Earth.
In the section, “How ICF Works” from the Lawrence Livermore National Laboratory website an overview of the attempts to develop internal confinement fusion since the 1940’s is detailed. In the earlier attempts magnetic fields are used in order “to confine hot, turbulent mixtures of ions and free electrons called plasmas so they can be heated to temperatures of 100 to 300 million kelvins.” With confined temperatures of that range heavy isotopes of hydrogen (deuterium and tritium) are capable of being fused into a heavy isotope of helium with a release of energy that is transformed from kinetic to heat as interactions with additional material takes place. Starting in the 1970’s, two types of inertial confinement fusion have been developed, the direct drive and indirect drive methods. The Indirect drive method is to be attempted first at National Ignition Facility, where “lasers heat the inner walls of a gold cavity called a hohlraum…” which will contain a tiny pellet of heavy hydrogen isotopes. This process is to result in the genesis of superhot plasma which radiates a uniform ‘bath’ of soft X-rays.” These x-rays will cause the surface of the fuel pellet to heat up and ablate very rapidly while the pellet itself implodes, creating a hot spot in the center where the fusion is triggered. If everything goes according to plan, the energy production of the fusion process itself will exceed that required to power the laser and initiate the process by 10 to 100 times. Success with this objective will provide the first steps towards viable fusion-powered energy in commercial power plants.
The Program at the National Ignition Facility:
What follows is a description of both the lasers that have been developed for use in the L.I.F.E. program and the facility in which the experiments are to take place.
In the report provided by the U.S. Department of Energy in March of 2009 it was announced that the largest laser ever developed had been completed at the National Ignition Facility. This achievement is expected to increase national security, decrease American dependence on foreign oil, and usher in an opportunity to experience breakthroughs in numerous scientific fields. It is noted that this has not been the first groundbreaking achievement to be realized by those at the National Ignition Facility, as earlier in March of 2009 the National Ignition Facility was the world’s first laser to exceed a megajoule by producing more than 25 times the previous energy record with a recorded 1.1 million joules of ultraviolet energy.
“The National Ignition Facility: Ushering in a New Age for Science” found on the Lawrence Livermore National Laboratory website provides a detailed overview of what the facility actually consists of. When experimentation begins in 2010 they will take place in a facility that has dimensions of a ten-story building and three football fields. Inside of this massive structure are 192 lasers which are expected to produce at least 60 times the energy of any existing laser system. Once everything is in place, approximately two million joules of energy can be targeted on the central chamber which will simulate conditions otherwise only found in cores of stars, gas giant planets, and nuclear weapons. All of this carried out for the purpose of providing “significant contributions to national and global security,” and opening the door to the possibility of fusion energy as a practical source of energy.
While there are likely to be multiple benefits that I did not touch upon in my research, the following paragraphs sum up what I felt to be the most important benefits that we stand to reap if the research being conducted is successful.
As it states in “Inertial Fusion Energy” on the Lawrence Livermore National Laboratory website, the program at the National Ignition Facility provides not only the opportunity to validate the viability of inertial fusion energy as a source for electricity, but just as importantly provides a potential energy source that is not dependent upon rare or non-renewable resources. The fuel(s) required for the National Ignition Facility’s fusion program are “derived from water and the metal lithium, a relatively abundant resource.” Unlike the limited surplus of petroleum, coal, natural gas, and other non-renewable energy sources, heavy hydrogen constitutes “one in every 6,500 atoms on Earth…” This provides a fuel that is not only available worldwide but one that compares quite favorably with current fuel resources. “One gallon of seawater would provide the equivalent energy of 300 gallons of gasoline; fuel from 50 cups of water contains the energy equivalent of two tons of coal.”
According to the article written by Gail Overton for LaserFocusWorld, there are numerous potential benefits to be derived from the research being performed at the National Ignition Facility as well as at similar laboratories around the world. Reducing the quantity of carbon dioxide that is released into the atmosphere by replacing current fossil-fuel power plants with nuclear fusion power plants and dramatically reducing the amount of nuclear waste that is left behind by the presently utilized nuclear fission power plants being the two most important benefits from an ecological perspective. However, not only would nuclear fusion reduce the amount of nuclear waste compared to what is produced by nuclear fission, but once the process was underway, it could be used to, “consume the available stockpiles of spent nuclear fuel…” thereby actually reducing the amount of preexisting nuclear waste that is already a cause for concern.
While there is no guarantee that the research being conducted at the National Ignition Facility will produce the results that are anticipated or that an industry developed around the process of inertial fusion energy production will arise with successful completion of the experiments that are underway, it is important that we explore new avenues and begin searching for new ways to both provide the necessary energy for our daily lives and diminish our negative impact on the world around us. There are numerous other alternatives being explored, and it may be that a combination of various energy sources is the best method available to us, but that requires that we explore these new potential sources of energy, and this paper was designed to sponsor an awareness of one particular method. If I have successfully provided a greater degree of understanding, both of the program located at the National Ignition Facility itself and of the benefits that we can hope to derive from that and related programs, then I have accomplished what I have set out to do.