250+ TOP MCQs on Classification of Nuclear Reactors and Answers

Power Systems Multiple Choice Questions on “Classification of Nuclear Reactors”.

1. Reactors used for electricity generation are called ______________
A. Research and development reactors
B. Production reactors
C. Power reactors
D. Electron reactors
Answer: C
Clarification: Power reactors are used for electrical power generation purpose. Research and development reactors are used for testing new reactor design ans research. Production reactors are used for converting fertile material into fissile materials.

2. What is the difference in size of thermal reactor and fast reactor?
A. Size of thermal reactor is slightly more than size of fast reactor
B. Size of thermal reactor is slightly less than size of fast reactor
C. Size of thermal reactor is very much larger than size of fast reactor
D. Both are of same size
Answer: C
Clarification: The moderator to fuel volume ratio for thermal reactor lies between 20 to 80. Same ratio for fast reactor is very less that’s why the size of thermal reactor is very much greater than size of fast reactors.

3. Which of the following reactors does not need moderator?
A. Thermal reactor
B. Fast reactor
C. Intermediate reactor
D. Power reactor
Answer: B
Clarification: In fast reactors fission is caused by fast neutrons, so there is no need of moderator to slow down the neutrons. While in other reactors fission is needed to be from slow or intermediate speed neutrons, so moderator is required to slow down the fast neutrons.

4. Heat energy generated in per unit volume of reactor core in thermal reactor is ___________
A. less than that in fast reactors
B. more than that in fast reactors
C. equal to that and fast reactors
D. unpredictable
Answer: A
Clarification: In fast reactors fission occurs due to fast moving neutrons. Hence, the rate of fission reaction is high and the heat energy generated is also very high. In thermal reactor moderator is used to slow down the neutrons and to make the fission in much more controlled way. So, heat generated in thermal reactor is cocomparatively less.

5. In which of the following reactors material converted into fissile materials is more than fissile material consumed?
A. Burner reactor
B. Slow reactors
C. Converter reactor
D. Breeder reactor
Answer: D
Clarification: Burner reactor or thermal reactor is designed only to consume fissile materials and to give heat energy. Converter reactor converts fertile material into fissile material but the rate of conversion is slower than rate of conception. Only breeder reactor from above options is such a reactor which converts fertile materials into fissile materials faster than consumption of fissile materials.

6. Which of the following reactors uses its fuel as coolant?
A. Direct reactor
B. Indirect reactor
C. Both direct and indirect reactor
D. Solid fuel reactor
Answer: A
Clarification: On the basis of cooling system employed reactors are of two types. One is Direct and another is indirect reactor. Direct reactor used as fuel in liquid form and it acts as coolant. It is circulated through the heat exchanger in which heat is transferred to water to produce steam.

7. Which of the following statement is true?
I. In homogeneous reactors the nuclear fuel and the moderator represents a uniform mixture in the fluid form.
II. In heterogeneous reactors separate fuel sludge or roads are inserted in the moderator
III. Most of the nuclear reactors used these days are of homogeneous type
A. Only statement I and II are true
B. Only statement I and III are true
C. Only statement II and III are true
D. Only statement III is true
Answer: A
Clarification: The statement I and II are true but statement III is wrong, because most of the reactors are of heterogeneous type. i.e.fuel is used in them are separate mostly in form of road fuel rod.

8. In which of the following reactor it is possible to add remove and process the reactor fuel during reactor operation?
A. Homogeneous reactor
B. Heterogeneous reactor
C. Solid fuel reactor
D. Both homogeneous and heterogeneous reactors
Answer: A
Clarification: In homogeneous reactor nuclear fuel and the moderator represent a uniform mixture, in the fluid form including gases liquids and slurries. Due to fluid form of fuel it is possible in homogeneous reactor that reactor fuel can be added removed and reprocessed during reactor operation without shutting in town.

9. In which of the following reactors fissile and fertile materials are kept separate?
A. In one region reactor
B. In two region reactor
C. In one and two region reactor
D. It is impossible to separate them
Answer: B
Clarification: As per arrangement of fertile and fissile materials the reactors are classified into categories. In first category of reactors fertile and fissile fuels are mixed and are called One Region Reactor. In second category of reactors a fertile and fissile material are separate and is called to Region Reactor.

10. Any leakage or component failure in primary nuclear fission reactor coolant system is dangerous.
A. True
B. False
Answer: A
Clarification: Above statement is true because these failures are very much difficult to repair. It is because of the presence of fission products in the coolant which can cause contamination.

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