HIGH TEMPERATURE APPLICATIONS: FUEL SYNTHESIS

As shown in Table II, liquid metal and gas-cooled reactors can generate very high temperatures, which could be used to create new synthetic fuels for energy. This will be an innovative application of nuclear energy and can considerably expand its use. This is because the transportation sector is responsible for about a quarter of the total energy use and almost 99% of this is currently supplied by organic fuel. Nuclear power can penetrate this large market through use of electric cars and production of synthetic fuels such as methanol, ethanol and their derivatives; nuclear power can also be used for coal gasification, oil extraction and hydrogen production. All of these are being seriously considered in the 21st century. However, the infrastructure for use of these fuels needs to be created first, particularly in the case of environmentally ideal hydrogen fuel.

Coal gasification (i. e., conversion of solid coal into a gaseous fuel like the natural gas) requires very high temperatures but could be practical because the infrastructure for use of natural gas already exists, and there are vast deposits of coal in the world and this conversion can remove environmental pollutants such as particulates like sulphur-dioxide and nitrogen oxides. The efficiency of coal fire plants will also be improved by coal gasification. The process of coal gasification is, however, quite energy intensive; one unit of gasified coal may require about 1.7 units of energy in solid coal13. High temperature gas-cooled reactors can play a role here.

Another possible use of nuclear energy is for oil extraction from tar and oil sands and for enhanced oil recovery operations, particularly from depleted oil deposits. Canada and Venezuela have large resources of oil and tar sands. Steam injection is used for these extraction applications and steam can also be used for processing the oil after the extraction.

The feasibility of nuclear application for production of more organic fuel really depends on the economics. So long as fossil fuel, particularly oil and gas, are available at low prices, nuclear will not be a preferable option. Only dual use, where nuclear electricity can compete in the market, could make these applications worthwhile.

Hydrogen economy has received renewed interest because of new developments in HTGR technologies. Several paths to hydrogen production are being considered: decomposition and gasification of fossil fuel such as steam reforming of methane and carbon dioxide reforming of methane; and decomposition of water, namely, low-temperature electrolysis, and combination of electricity and heat for high temperature electrolysis. These are briefly described below.

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