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Our Developing World新概念英语课程讲解
新概念英语 Our Developing World我们发展中的世界
Faith in controlled nuclear fission is now being shown by the construction of atomic power stations.
In Britain, Calder Hall on the coast of Cumberland first made its contribution to the National Electricity grid in 1957.
Subsequently a chain of nuclear power stations was planned.
Of necessity they are sited near the coasts or tidal water because of the need of much water for cooling and a certain discharge of possible radioactive effluent.
Atomic power is associated in the public mind with the destructive force of atom bombs and partly for this reason, though it is claimed that there is no danger to be associated with atomic power stations, they are being sited away from populous centres.
The present position is that the three main sources of power are coal, oil and water power.
We sometimes refer to electricity ,gas or petrol as if they were the actual source of power , forgetting that electricity must be generated by the consumption of coal or oil or by the utilization of water power, whilst coke,gas and petrol are examples of secondary fuels by which coal and oil may be more effectively used.
Where alternative sources of power are available there are some marked contrasts in handling.
The bulk and weight of coal required in the majority of manufacturing industries is large in comparison with the bulk and weight of other raw materials.
This is not always true--was with the manufacture of pig iron and steel from low-grade iron ores-- but it did lead to the concentration of industrial developments on the coal-fields, a phenomenon well seen in such countries as Britain where the Industrial Revolution came before the days of oil or electricity.
Coal being a solid must be distributed mainly by rail or water.
By way of contrast oil can be transported large distances by pipeline but overseas movement has involved building of large numbers of tankers, including now some of the largest vessels afloat.
Unless suitable on other grounds oilfields have not become industrial regions; on the contrary the oil industry is marked by a certain amount of smell and an element of danger, hence the siting of refineries at a distance from population centres.
It is not always realized that the owners of pipelines can handle the oil of different customers, sending it through at different, periods.
Natural gas can also be transported large distances by pipe.
Early in 1959 Britain received the first ship cargo of natural gas----liquefied for the purpose of transport.
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