Chapter 11 Multiple choice questions

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. The world uranium resource is described in Section 11.3. The world's reactors use more uranium than is being mined. Where does the rest come from?

Uranium bred from thorium correct incorrect

Uranium from spent fuel recycled by reprocessing correct incorrect

Stocks of military uranium for nuclear weapons correct incorrect

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. Section 11.4 describes solutions to any possible uranium shortage. The 'burn-up' of reactors is described on pages 427 and 428. This relates the heat output to the reactor throughput of fuel. Early reactors, such as the Magnox design, running on natural uranium had burn-ups or around 5 GW-days per tonne of uranium. What level of uranium enrichment might be needed in future reactors to achieve a burn-up of 100 GW-days per tonne?

3.5% correct incorrect

5% correct incorrect

Almost 10% correct incorrect

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. Section 11.5 describes nuclear power and safety. In the event of a nuclear accident, various fission products may be released into the environment and absorbed by the human body. Which fission isotope is absorbed by the thyroid gland?

Strontium-90 correct incorrect

Caesium-137 correct incorrect

Iodine-131 correct incorrect

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. Box 11.2 describes four significant nuclear accidents. Three of the reactor buildings at Fukushima were destroyed by hydrogen explosions. Where did the hydrogen come from?

Electrolysis of water leaking into the generators correct incorrect

Hydrogen fuel leakage from fuel cells correct incorrect

From a chemical reaction between the zirconium fuel cladding and steam correct incorrect

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. Section 11.6 describes waste disposal and decommissioning. The quantities of materials in the nuclear fuel cycle are described in Figure 11.8. In order to fuel a 1 GW power station for a year, roughly how many tonnes of yellowcake (uranium oxide) need to be supplied from the uranium-producing country to a conversion plant in the uranium-using one?

10,000 tonnes correct incorrect

1000 tonnes correct incorrect

250 tonnes correct incorrect

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. Section 11.7 describes generation costs for nuclear power. Roughly what proportion is made up by the fuel costs?

3% correct incorrect

5% correct incorrect

10% correct incorrect

25% correct incorrect

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. Mixed oxide fuel (MOX) is described in Sections 11.4 and 11.8. What exactly is it?

A mixture of plutonium oxide and the oxide of depleted uranium correct incorrect

A mixture of depleted uranium oxide and natural uranium oxide correct incorrect

A mixture of highly enriched uranium oxide and depleted uranium oxide correct incorrect

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. Reprocessing is described in Section 11.8. The text describes a 2003 report by the Massachusetts Institute of Technology. By how much did they estimate that reprocessing saved on uranium demand compared to a simple open fuel cycle?

10% correct incorrect

16% correct incorrect

25% correct incorrect

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. The use of thorium as a potential nuclear fuel is also described in Section 11.8. What fissile isotope can be produced by bombarding thorium 232 with fast neutrons?

Plutonium-239 correct incorrect

Uranium-233 correct incorrect

Uranium-235 correct incorrect

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. Section 11.8 also describes nuclear fusion. In a Tokamak system, the deuterium and tritium is contained by a strong magnetic field. Why is this method necessary?

A very high flow of hydrogen is required through the system. correct incorrect

Tritium is highly corrosive to metals. correct incorrect

The reaction temperature is very high indeed. correct incorrect