Section II

PART 2

• Look through the text and give an appropriate title to it.

With deuterium and tritium as the fuel, the fusion reactor would be an effectively inexhaustible source of energy. Deuterium is ob­tained from sea-water. About one in every 3,000 water molecules con­tains a deuterium atom. There is enough deuterium in the oceans to provide for the world's energy needs for billions of years. One gram of fusion fuel can produce as much energy as 9,000 litres of oil. The amount of deuterium found naturally in one litre of water is the energy equivalent of 300 litres of gasoline. Tritium is bred in the fusion reactor. It is generated in the lithium blanket as a product of the reaction in which neutrons are captured by the lithium nuclei.

A fusion reactor would have several attractive safety features. First, it is not subject to a runaway, or "meltdown" accident as is a fission reactor. The fusion reaction is not a chain reaction. It requires a hot plasma. Accidental interruption of a plasma control system would extinguish the plasma and terminate fusion.

Second, the products of a fusion reaction are not radioactive; hence, no long-term radioactive wastes would be generated. Neu­tron bombardment would activate the walls of the containment ves­sel, but such activated material is shorter-lived and less toxic than the waste products of a fission reactor. (Moreover, even this activa­tion problem may be eliminated, either by the development of ad­vanced, low-activation materials, such as vanadium-based materi­als, or by the employment of "advanced" fusion-fuel cycles that do not produce neutrons, such as the fusion of deuterons with helium-3 nuclei. Nearly neutron-free fusion systems, which require higher temperatures than D-T fusion, might make up a "second genera­tion" of fusion reactors.) Finally, a fusion reactor would not release the gaseous pollutants that accompany the combustion of fossil fu­els; hence, fusion would not produce a greenhouse effect.

* Answer the following questions using the information from the text.

a) What is deuterium obtained from?

b) How much energy can one gram of fusion fuel produce?

110 Section I. Power Engineering

c) What does the fusion reaction require?

d) What are the advantages of fusion reactor?

JUST FOR FUN

• Read this joke and smile. Tell your friend.

SCIENTISTS SMILE

Simple Experiment

Here is a simple experiment that will teach you an important elec­trical lesson: On a cool, dry day, scuff¹ your feet along a carpet, then reach your hand into a friend's mouth and touch one of his dental fillings². Did you notice how your friend twitched Violently and cried out in pain? This teaches us that electricity can be a very powerful force, but we must never use it to hurt others unless we need to learn an im­portant electrical lesson.

Dave Barry, "What is Electricity?"

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