As the cost of oil skyrockets, worldwide demand increases and supplies decrease. All forms of energy production are increasing as well; the cost to mine and ship coal has doubled in the past year. At the same time, the percentage of greenhouse gases in the atmosphere continue to increase, while public awareness of the effects of global warming changes the way we think about natural resources. Electricity is the form of energy we most depend upon and this dependence will only increase with time. In the world of tomorrow, electricity will charge electric cars batteries, produce hydrogen cheaply for fuel cell-powered vehicles, and possibly heat buildings in order to reduce the dependence on fossil fuels.
The question is where will all this power come from? At best, the electricity generated from wind, solar, and hydroelectric will supply 20% of our need—possibly even less 50 years from now, which leaves coal and nuclear fuels as the primary source for energy. The big problem with coal-fired generators, however, is the release of radiation, airborne mercury, and carbon dioxide (CO2) into the atmosphere. As a clean source of energy nuclear fission reactors will generate the needed power for the next 50 years. After that, it's hoped that fusion reactors (which combine small atoms to make bigger ones instead of breaking heavy atoms apart into smaller ones) will solve the energy needs.
The circular form in the center of this photo is for the hatch that will provide access for moving equipment through the containment walls into the center of the structure. Note the heavy reinforcement in the outer protective structure wall to the right of the photo. |
The greatest cost of producing electricity from nuclear power plants is the initial cost of construction. The goal is to build better plants with longer life expectancies on a shorter construction cycle. David Matthews, director of the division of new reactor licensing at the Nuclear Regulatory Commission (NRC), Washington, D.C., says that before the Three Mile Island (TMI) accident in 1979, it took, on average, a little more than five years to build a new nuclear power plant following issuance of a construction permit by the NRC. After the accident, the process took more than 11 years, making the it prohibitively expensive. The NRC is reducing the permitting time by precertifying standardized power plant designs submitted by reactor manufacturers such as AREVA, General Electric, Mitsubishi, and Westinghouse. These certified designs then can be built at locations around the country, while owners apply for a combined construction and operating license (COL). This process is expected to lead to a reduction in construction time, in contrast to the lengthy delays experienced during the post-TMI period, because the design is expected to be essentially complete before the start of construction. The design life for reactors built in the 1970s and 1980s was 40 years. However, most of these plants have performed well and have been recertified for an additional 20 years. The current thought is that most will win certification for an additional 20 years after that, making the cost of producing electricity very reasonable. New reactor facilities may start with certifications of 40 years but with a design life of 60. Given the advancements in concrete technology, it should be possible to specify 100-year and longer service lives; this is also done with structural concrete bridges today. It means that the extended service life of a reactor will depend more on improvements to the steel vessels that contain the nuclear reaction.
The technology of pumping concrete and placing under extreme conditions has changed significantly since the Generation II reactor constructions in the United States, allowing for reduced construction times and greater efficiencies with new constructions. Temporary protective structures like the one shown here were used throughout the first two years of construction on the Olkiluoto 3 facility. |
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http://www.concreteconstruction.net/industry-news-print.asp?sectionID=718&articleID=755617
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