Power Systems Multiple Choice Questions on “Nuclear Reaction”.
1. In nuclear power stations which nuclear reaction is performed?
A. Nuclear fission
B. Nuclear fusion
C. 90% fission and 10% fusion
D. 90% fusion and 10% fission
Answer: A
Clarification: Nuclear fission is the process in which heavy nucleus is split when it is bombarded by certain partials. Huge amount of energy is released during nuclfclear fission in form of heat and radiation.
2. Which particle is bombarded on heavy nucleus of nuclear fuel?
A. Electron
B. Proton
C. Neutron
D. Photon
Answer: C
Clarification: Nuclear fission involvs bombardment of certain particles on heavy nucleus causing it to split. All modern fission reactors uses neutron particles for this purpose because they are neutral in charge and so, they can make their way through the shells of electrons and then through the nucleus at low energy.
3. The critical mass for U235 fission reaction is about _____________
A. 100Kg
B. 200 Kg
C. 50 kg
D. 10 kg
Answer: D
Clarification: For a chain reaction to occur the sample of the fissionable material should be large enough to capture the neutron internally. The minimum mass of fissionable material required to sustain a chain reaction is called the Critical Mass”. The critical mass varies for each reaction, for U235 fission reaction it is about 10 Kg.
4. The fuel mainly used in nuclear fission reactors are:
A. U235
B. U239
C. U233
D. U238
Answer: A
Clarification: The materials U235,U233 and Pu239 are called fissionable materials. From all the above mentioned fuels only U235 will fission in chain reaction.
5. Which fissionable nuclear fuel occur in nature?
A. Plutonium
B. Thorium
C. Uranium
D. 94239 Pu
Answer: C
Clarification: The only natural fissionable fuel occurring in our nature is Uranium, of which 99.3% is U238 and 0.7% is U235 and U234 is only a trace. Out of these isotopes only U235 will fission in chain reaction.
6. Which of the following has high fission percentage?
A. Pu239
B. U233
C. U235
D. U234
Answer: C
Clarification: U235 has higher fission percentage in comparison to others. U235 is only fissionable nuclear fuel found in nature, Pu239 and U233 are produced artificially. They are fissionable.
7. Reactors used for converting fertile materials to fissile materials are called _____
A. research and development reactor
B. production reactor
C. power reactors
D. slow reactors
Answer: B
Clarification: Research and development reactors are used for testing new reactor designs and research. Production reactors are used for converting fertile materials into fissile materials and Power reactors are used for generation of electrical energy.
8. Which statement about fast reactor is true?
A. These reactors are big in size so not easier to shield
B. Fast reactors can convert fertile materials to fissile materials
C. Fast reactors are easy to control
D. Heat transfer and cooling is very easy and simple
Answer: B
Clarification: Fast reactors can convert more fertile material to fissile materials with the result that the net fuel consumption for such reactors is much less. These reactors are small and compact and so easier to shield. Heat transfer and cooling problems in the core are accomplished due to high power density.
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