Battery Switch Technology


Monday, January 18, 2010

Hydrogen From Nuclear Energy

Hydrogen offers great promise for future domestic energy use. It can be produced using a variety of resources and technologies. One group of production technologies uses nuclear energy. Nuclear energy can produce high quality hydrogen in large quantities at a relatively low cost without any air emissions. Currently, the most viable hydrogen production technology utilizing nuclear energy is conventional electrolysis, which uses electric energy to split water into hydrogen and oxygen. 

Light Water Reactors (LWRs), the most common type of reactor used today, can produce hydrogen, electricity or both. As the cost of electrolysis comes down and the cost of fossil fuels rise, nuclear production of hydrogen by electrolysis of water using nuclear produced electricity is increasingly attractive. However, in the longer term (after about 2020), the most promising nuclear hydrogen production technologies will likely use the high temperatures generated in advanced, high temperature gas reactors (HGTRs). These advanced reactors are more efficient and will be able to provide more economical, large-scale hydrogen production with less nuclear waste and energy use overall.

First, the Basics

Today, there are approximately 437 nuclear power reactors operating in over 25 countries around the world with a total output of some 350,000 megawatts. An additional 28 reactors (27,000 MWe) are currently under construction in 10 countries. Today, the U.S. has 103 LWRs on 64 sites in 31 states. U.S. nuclear reactors supply approximately 20 percent of the country's electricity needs, or 780.2 billion kWh a year. Uranium is the main fuel for nuclear reactors, and is readily available. 

Today, 16 countries account for over 99 percent of global uranium production, about 90 million pounds per year.

Major suppliers exist in the U.S., Canada and Australia, with Canadian and Australian uranium mines today supplying over 50 percent of the world's uranium. Compared to natural gas or coal, uranium is low in cost, and the cost of nuclear electricity is less sensitive to its price fluctuations. One uranium fuel pellet, about the size of the tip of your little finger, has the equivalent energy potential of 17,000 cubic feet of natural gas, 1,780 pounds of coal, or 149 gallons of oil. Nuclear reactors emit no air emissions; however, spent fuel must be disposed of properly.

Today's coal fired power plants producing the same amount of electricity as the current U.S. nuclear plants would produce 630 million tons of carbon dioxide (CO2), 2.6 million tons of nitrogen oxide (NOx) and 5.6 million tons of (sulfur dioxide) SO2  annually. Nuclear reactors use a controlled nuclear fission reaction to release large amounts of heat to make steam that drives a turbine to create electricity. 

The core of a 1,000 megawatt LWR contains about 75 tons of enriched uranium. A coolant, water in today's reactors, is pumped through the reactor to carry away the heat produced from the nuclear fission reaction. The resulting steam drives a steam turbine electric generator, which produces about 7 billion kilowatt-hours (kWh) of electricity per year—enough to power about 500,000 to 700,000 homes. Every 18 to 24 months,about one-third of the spent fuel is removed and replaced with fresh fuel.

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