05-12-2012, 02:35 PM
Paper Presentation : Energy Generation from Thorium
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Abstract :
An alerting statistic is that there are now over 3 billion mobile phones on earth; one for every two people. The world is undergoing a communication/energy revolution whose rate of change is many magnitudes larger than anything yet experienced by mankind. Communication and energy usage are linked simply because all people are now able to see how the high energy consumers live – and whatever their culture, it is apparent that they all aspire to high tech gadgetry, instant information, participation in the popular fashions and entertainments.
Thorium is abundant and clean enough to supply global energy demand for centuries. According to experts there is more energy available from thorium than all coal, gas, oil and uranium combined. Considered by many as the future of nuclear energy generation, Thorium operates significantly cleaner than uranium-based power plants as the waste products are much easier to handle. A ton of Thorium produces the same energy as 200 tons of uranium, or 3.5 million tons of coal.
Introduction :
This has resulted in an unprecedented migration to cities, or in some societies creation of brand new cities. The result is an unprecedented demand for energy consuming devices and transport facilities. The Western world, apart from France, which can export its nuclear electricity, has been caught unprepared for the escalating global appetite for energy. Perhaps the prime example is the UK, which since the 1970s has closed down its coal mines,
The Liquid Fluoride Thorium Reactor :
The liquid fluoride thorium reactor (LFTR; spoken as lifter) is a thermal breeder reactor which uses the thorium fuel cycle in a fluoride-based molten (liquid) salt fuel to achieve high operating temperatures at atmospheric pressure. The LFTR is a type of thorium molten salt reactor (TMSR). Molten-salt-fueled reactors(MSRs) such as LFTR, where the nuclear fuel itself is in the form of liquid molten salt mixture, should not be confused with the solid-fueled Fluoride salt-cooled high temperature reactors (FHRs).
In a LFTR, thorium and uranium-233 are dissolved in carrier salts, forming a liquid fuel. Typical operation sees the liquid fuel salt being pumped between a critical core and an external heat exchanger, where the heat is transferred to a nonradioactive secondary salt, that then transfers its heat again to a steam turbine or closed-cycle gas turbine.
This technology was first investigated at the Oak Ridge National Laboratory Molten-Salt Reactor Experiment in the 1960s. It has recently been the subject of a renewed interest worldwide. Japan, China, the UK, as well as private US, Czech and Australian companies have expressed intent to develop and commercialize the technology.
Energy Production
Because nearly all of the thorium is used up in an LFTR (versus only about 0.7% of uranium mined for an LWR), the reactor achieves high energy production per metric ton of fuel ore, on the order of 300 times the output of a typical uranium LWR. The LFTR allows much higher operating temperatures than does a typical LWR therefore a higher thermodynamic efficiency. The turbine system believed best suited for its operation is a triple-reheat closed-cycle helium turbine system, which should convert 50% of the reactor heat into electricity compared to today's steam cycle (~25% to 33%). This efficiency gain translates to about 4.11 million barrels of crude oil equivalent per year more than that generated by a steam system. Capital costs are lower due to smaller reactor & turbo-machinery size, low reactor pressures and minimal redundant safety systems. The greater energy production capability of LFTRs means we estimate the cost for electricity from a LFTR plant could be 25% to over 50% less than that from a LWR.
Conclusion :
LFTR technology has the potential for:
-High-temperature
-Low-pressure
- Very low waste generation (and ready use of recovered “wastes”)
- Sustainable resource base
In addition to electricity generation, concentrated thermal energy from LFTR can enable other applications:
Industrial process heat for many uses
Desalination of water [30]
Hydrogen production by water splitting
Combined heat and power
Nuclear marine propulsion
Also high-temperature generation offers deployment flexibility and the Air-cooling enables deployment away from water sources. Thorium fuel offers deployment and supply stability and the Dense fuel source enables lifetime fuel commitments.
In this context the need for more efficient safer and more secure nuclear power generators is urgent. The Thorium cycle must be introduced as early as possible to complement the inevitable upsurge in Uranium installations. Thorium is four times as abundant as Uranium and can eliminate the ghastly end products of the Uranium cycle.