Information About Next Generation Nuclear Power
Rising electricity prices and last summer’s rolling blackouts in California have focused fresh attention on nuclear power’s key role in keeping America’s lights on. Today 103 nuclear plants crank out a fifth of the nation’s total electrical output. And despite residual public misgivings over Three Mile Island and Chernobyl, the industry has learned its lessons and established a solid safety record during the past decade. Meanwhile the efficiency and reliability of nuclear plants have climbed to record levels. Now with the ongoing debate about reducing greenhouse gases to avoid the potential onset of global warming, more people are recognizing that nuclear reactors produce electricity without discharging into the air carbon dioxide or pollutants such as nitrogen oxides and smog-causing sulfur compounds. The world demand for energy is projected to rise by about 50 percent by 2030 and to nearly double by 2050. Clearly, the time seems right to reconsider the future of nuclear power. An essay writer is a person whose job is to create articles and this important topic of nuclear information will also be presented in the form of essay.
No new nuclear plant has been ordered in the U.S. since 1978, nor has a plant been finished since 1995. Resumption of large-scale nuclear plant construction requires that challenging questions be addressed regarding the achievement of economic viability, improved operating safety, efficient waste management and resource utilization, as well as weapons nonproliferation, all of which are influenced by the design of the nuclear reactor system that is chosen.
Designers of new nuclear systems are adopting novel approaches in the attempt to attain success. First, they are embracing a system-wide view of the nuclear fuel cycle that encompasses all steps from the mining of ore through the management of wastes and the development of the infrastructure to support these steps. Second, they are evaluating systems in terms of their sustainability—meeting present needs without jeopardizing the ability of future generations to prosper. It is a strategy that helps to illuminate the relation between energy supplies and the needs of the environment and society. This emphasis on sustainability can lead to the development of nuclear energy–derived products besides electrical power, such as hydrogen fuel for transportation. It also promotes the exploration of alternative reactor designs and nuclear fuel–recycling processes that could yield significant reductions in waste while recovering more of the energy contained in uranium. The writer assigned to write my essay for me task related to nuclear informational essay is qualified to the same academic level or higher than your writing requirements.
We believe that wide-scale deployment of nuclear power technology offers substantial advantages over other energy sources yet faces significant challenges regarding the best way to make it fit into the future.
Future Nuclear Systems
In Response to the difficulties in achieving sustainability, a sufficiently high degree of safety and a competitive economic basis for nuclear power, the U.S. Department of Energy initiated the Generation IV program in 1999. Generation IV refers to the broad division of nuclear designs into four categories: early prototype reactors (Generation I), the large central station nuclear power plants of today (Generation II), the advanced lightwater reactors and other systems with inherent safety features that have been designed in recent years (Generation III), and the next-generation systems to be designed and built two decades from now (Generation IV) [see box on opposite page]. By 2000 international interest in the Generation IV project had resulted in a nine-country coalition that includes Argentina, Brazil, Canada, France, Japan, South Africa, South Korea, the U.K. and the U.S. Participating states are mapping out and collaborating on the research and development of future nuclear energy systems.
Although the Generation IV program is exploring a wide variety of new systems, a few examples serve to illustrate the broad approaches reactor designers are developing to meet their objectives. These next-generation systems are based on three general classes of reactors: gascooled, water-cooled and fast-spectrum. The writer assigned to write my essay request about nuclear topic is qualified to the same academic level or higher than your writing requirements.
Nuclear reactors using gas (usually helium or carbon dioxide) as a core coolant have been built and operated successfully but have achieved only limited use to date. An especially exciting prospect known as the pebble-bed modular reactor possesses many design features that go a good way toward meeting Generation IV goals. This gascooled system is being pursued by engineering teams in China, South Africa and the U.S. South Africa plans to build a full-size prototype and begin operation in 2006.
The pebble-bed reactor design is based on a fundamental fuel element, called a pebble, that is a billiard-ball-size graphite sphere containing about 15,000 uranium oxide particles with the diameter of poppy seeds. The evenly dispersed particles each have several high-density coatings on them. One of the layers, composed of tough silicon carbide ceramic, serves as a pressure vessel to retain the products of nuclear fission during reactor operation or accidental temperature excursions. About 330,000 of these spherical fuel pebbles are placed into a metal vessel surrounded by a shield of graphite blocks. In addition, as many as 100,000 unfueled graphite pebbles are loaded into the core to shape its power and temperature distribution by spacing out the hot fuel pebbles.
Heat-resistant refractory materials are used throughout the core to allow the pebble-bed system to operate much hotter than the 300 degree Celsius temperatures typically produced in today’s light-water-cooled (Generation II) designs. The helium working fluid, exiting the core at 900 degrees C, is fed directly into a gas turbine/generator system that generates electricity at a comparatively high 40 percent thermal efficiency level, one quarter better than current lightwater reactors.
The comparatively small size and the general simplicity of pebble-bed reactor designs add to their economic feasibility. Each power module, producing 120 megawatts of electrical output, can be deployed in a unit one tenth the size of today’s central station plants, which permits the development of more flexible, modest-scale projects that may offer more favorable economic results. For example, modular systems can be manufactured in the factory and then shipped to the construction site.
The pebble-bed system’s relative simplicity compared with current designs is dramatic: these units have only about two dozen major plant subsystems, compared with about 200 in light-water reactors. Significantly, the operation of these plants can be extended into a temperature range that makes possible the low emissions production of hydrogen from water or other feedstocks for use in fuel cells and clean-burning transportation engines, technologies on which a sustainable hydrogen-based energy economy could be based. Hire a reliable free essay writer who will create an original content about nuclear energy and deliver it on time.
These next-generation reactors incorporate several important safety features as well. Being a noble gas, the helium coolant will not react with other materials, even at high temperatures. Further, because the fuel elements and reactor core are made of refractory materials, they cannot melt and will degrade only at the extremely high temperatures encountered in accidents (more than 1,600 degrees C), a characteristic that affords a considerable margin of operating safety.
Yet other safety benefits accrue from the continuous, on-line fashion in which the core is refueled: during operation, one pebble is removed from the bottom of the core about once a minute as a replacement is placed on top. In this way, all the pebbles gradually move down through the core like gumballs in a dispensing machine, taking about six months to do so. This feature means that the system contains the optimum amount of fuel for operation, with little extra fissile reactivity. It eliminates an entire class of excess-reactivity accidents that can occur in current water-cooled reactors. Also, the steady movement of pebbles through regions of high and low power production means that each experiences less extreme operating conditions on average than do fixed fuel con-figurations, again adding to the unit’s safety margin. After use, the spent pebbles must be placed in long-term storage repositories, the same way that used-up fuel rods are handled today.