Questão 14

(IFSC) Texto para as próximas 3 questões.
 
Iran’s Nuclear Enrichment 
 
Enriching uranium so that it can be used for nuclear power − or building a weapon of mass destruction − lies at the heart of the controversy surrounding Iran’s nuclear programme. The point of enrichment is to boost the ratio in uranium of the uranium-235 isotope, which splits in a chain reaction and release energy. 
Enriching the uranium to the point where it comprises three to five percent of uranium-235 enables engineers to make fuel for a nuclear reactor, which requires a slow, controllable chain reaction. But by boosting the U-235 to 90 percent or more, engineers can make the material for a nuclear bomb, which needs a very fast, violent fissile process. The enrichment method used by Iran − which has now admitted to the International Atomic Energy Agency that is building a second uranium processing site − is a classic type in which uranium hexafluoride (UF6) gas is whizzed around in a centrifuge at very high speeds. A different isotope of uranium, called uranium-238, is separated from the mass by this centrifugal force. […] When the desired enrichment level is reached, the gas is converted by chemical process to a uranium oxide (UO2) which is used as fuel pellets for a nuclear reactor. If a bomb is sought, highly enriched oxide is engineered into ingots of uranium metal. But for a bomb to work, there has to be enough material to generate a critical mass that sustains the chain reaction. The bomb-maker also has to master the key technologies of shaping the charge and controlling the detonation sequence so that critical mass actually happens, rather than fizzes out, and occurs at the desired time rather than prematurely or accidentally. 
Iran is under suspicious by Washington and other nations of wanting to build a nuclear bomb. It replies that its programme is only for peaceful purposes. 
 
Disponível em: http://technology.iafrica.com 
 
According to the text, choose the correct alternative(s) to complete the sentence(s): 
The Iran’s enrichment… 
a)
V
F
is accepted by Washington and other nations. 
b)
V
F
is a programme for only peaceful intentions. 
c)
V
F
will be used only for nuclear power. 
d)
V
F
is recognized by the International Atomic Energy Agency. 
e)
V
F
creates a controversy around the world. 
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