NUCLEAR ENGINEERING Interview Questions and Answers :-

1) Neutrons have mass approximately equal to that of __________ atoms.

A. hydrogen
B. helium
C. deuterium
D. none of these
ANS:- A

2) Pick out the wrong statement.

A. The ratio of the density of the ‘nucleus’ to that of the ‘atom’ is 1012 .
B. a-particle is identical with a doubly charged helium ion.
C. The mass of deuterium atom is half that of helium atom.
D. Gamma rays are high energy electrons.
ANS:- D

3) The disintegration rate of a radioactive element

A. progressively increases.
B. progressively decreases.
C. remains constant throughout.
D. may increase or decrease depending on the material.
ANS:- B

NUCLEAR ENGINEERING Interview Questions and Answers
NUCLEAR ENGINEERING Interview Questions and Answers

4) Heavy water used in the nuclear reactors to slow down the speed of neutrons is

A. highly purified water.
B. a compound of oxygen and deuterium.
C. water having dissolved salts of heavy metals.
D. none of these.
ANS:- B

5) Pressure of CO2 gas (which is a coolant) in the Calder-Hall nuclear reactor is __________ kgf/cm2 .

A. 0.2
B. 7
C. 35
D. 50
ANS:- B

6) The electric power generation cost in nuclear power plant is less than that in a coal based thermal power plant, mainly because the

A. fuel cost per unit power generated is less.
B. thermal efficiency of the former is higher.
C. maintenance cost of the former is less.
D. none of these.
ANS:- A

7) Pick out the wrong statement.

A. Atoms with same number of nucleons but different number of protons are called isobars.
B. Atoms with same number of protons but different number of nucleons are called isoters.
C. Out of a, ß, and ?-rays, the one having maximum penetration power are ?-rays.
D. The product formed by emission of a-particle has mass number less by 4 units than the parent nuclide.
ANS:- B

8) Molten sodium is used as a coolant in a fast breeder reactor, because of its

A. excellent moderating properties.
B. neutron breeding capability.
C. faster heat removal capability from the core.
D. capability to increase the reaction rate in the core.
ANS:- C

9) Which of the following is the most harmful for the human being?

A. ß-rays
B. X-rays
C. ?-rays
D. ultra violet rays
ANS:- C

10) Coolant used in a fast breeder reactor is

A. molten sodium
B. heavy water
C. ordinary water
D. helium
ANS:- A

11) An element having large number of __________ is most easily subjected to nuclear fission.

A. protons
B. electrons
C. neutrons
D. nucleons
ANS:- D

12) Heavy water is preferred over ordinary water as a coolant, because it.

A. acts both as an efficient coolant as well as a moderator.
B. can be heated to a higher temperature without pressurizing.
C. is less prone to radiation damage.
D. all (a), (b) and (c).
ANS:- D

13) The ratio of mass of a neutron to that of an electron is about 1839. What is the ratio of the mass of a proton to that of an electron?

A. 159
B. 1837
C. 2537
D. 10000
ANS:- B

14) The number of neutrons in the nucleus of Uranium-233 (92U233) is

A. 141
B. 92
C. 233
D. 325
ANS:- A

15) Which of the following gases has very high neutron capture cross-section, making it unsuitable as a coolant in nuclear reactor?

A. N2
B. He
C. CO2
D. H2
ANS:- A

16) Nuclear power reactor located at Tarapur is of __________ type.

A. fast breeder
B. pressurised water
C. boiling water
D. gas cooled
ANS:- C

17) Which of the following is not an ore of uranium?

A. Pitchblende
B. Kyanite
C. Carnotite
D. Rescolite
ANS:- B

18) The main purpose of control rod in a nuclear reactor is to control the

A. chain reaction and hence the power output by regulating the number of secondary neutrons causing fission.
B. emission of hazardous radiation.
C. conversion of fissile material into fertile material.
D. velocity of the secondary neutrons.
ANS:- A

19) Secondary cooling circuit is a must in molten sodium cooled fast breeder reactor for

A. achieving high degree of superheat in the steam.
B. faster heat removal rate from the core.
C. lowering the coolant circulation pressure.
D. avoiding the mixing of water with radioactive sodium, as it may cause explosion.
ANS:- D

20) What is the average life of a radioactive atom having a ‘half life period’ of T?

A. 1.44 T
B. 0.144 T
C. 14.4 T
D. 2T
ANS:- A

21) Use of molten metal as a coolant in fast breeder reactor helps in

A. rapid heat transfer from the core.
B. accelerating the reaction rate in the core.
C. breeding neutrons.
D. accelerating the neutrons.
ANS:- A

22) Which of the following is a non-fissile material?

A. Plutonium-239
B. Uranium-235
C. Uranium-233
D. Thorium-232
ANS:- D

23) Candu reactor is a __________ nuclcear reactor.

A. natural uranium fuelled heavy water cooled & moderated
B. highly enriched uranium (85% U-235) fuelled
C. homogeneous
D. fast breeder
ANS:- A

24) Percentage of natural uranium present in uranium ore found in Jadugoda (Jharkhand) is

A. 0.1
B. 1
C. 3
D. 12
ANS:- A

25) Nucleus of tritium has __________ neutrons.

A. 1
B. 2
C. 3
D. 5
ANS:- B

26) Bhabha Atomic Research Centre (BARC) located at Trombay (near Bombay) has

A. five operating research reactors (namely Apsara, Cirus Zerelina, Purnima and Dhurva).
B. a 420 MW nuclear power plant.
C. a very large capacity (100 tons/yr) heavy water plant.
D. all (a), (b) and (c).
ANS:- A

27) U-235 content in enriched uranium, that is normally used in power reactors (e.g., at Tarapur atomic power plant), is about __________ percent.

A. 85
B. 50
C. 3
D. 97
ANS:- C

28) A fast breeder reactor

A. utilises fast neutrons for causing fission.
B. converts fertile material (e.g., U-238) into fissile material (Pu-239).
C. normally employs molten sodium as coolant.
D. all (a), (b) and (c).
ANS:- D

29) H2 is a better coolant than CO2, due to its relatively

A. lower density.
B. higher specific heat.
C. non-reactivity to uranium.
D. lower neutron capture cross-section.
ANS:- B

30) The half life period of a radiactive element is 100 days. After 400 days, one gm of the element will be reduced to __________ gm.

A. 1/4
B. 1/8
C. 1/2
D. 1/16
ANS:- D

31) First experimental observation of nuclear fission was done by

A. Plane
B. Rutherford
C. Fermi
D. Hahn and Strassman
ANS:- C

32) Coolant present in the primary circuit of a pressurised water reactor is high pressure

A. sub cooled water
B. saturated water
C. superheated steam
D. saturated steam
ANS:- B

33) Extraction of uranium from its ore is done using __________ methods.

A. electrometallurgical
B. pyrometallurgical
C. chemical
D. physical beneficiation
ANS:- C

34) The emission of an a-particle causes the resultant nucleus to have

A. more atomic weight and less atomic number.
B. less atomic weight and less atomic number.
C. less atomic weight and more atomic number.
D. none of these.
ANS:- A

35) ‘Light water’ used as a coolant in nuclear reactor is nothing but

A. ordinary water.
B. mildly acidic (pH = 6) water.
C. mildly alkaline (pH = 8) water.
D. none of these.
ANS:- A

36) Fast breeder reactors are most usable in India, because of our largest __________ deposits.

A. thorium
B. plutonium
C. uranium
D. none of these
ANS:- A

37) The main ore of thorium is

A. pitchblende
B. monazite sand
C. limonite
D. galena
ANS:- B

38) Critical energy should be __________ the neutron binding energy of the atom in order to initiate a nuclear fission.

A. equal to
B. less than
C. more than
D. either more or less==
ANS:- C

39) In nuclear reactions, __________ number is conserved.

A. mass
B. atomic
C. both (a) & (b)
D. neither (a) nor (b)
ANS:- C

40) The ratio of neutrons to protons of an element having a mass number and atomic number of 80 and 40 respectively is

A. 1
B. 0.5
C. 2
D. 4
ANS:- A

41) Function of control rod in a nuclear reactor is to control

A. temperature
B. pressure
C. fuel consumption
D. absorption of neutrons
ANS:- D

42) The main ore of uranium is

A. pitchblende
B. monazite sand
C. cassiterite
D. chalcopyrite
ANS:- A

43) Which of the following nuclear materials is fissile?

A. Uranium-238
B. Thorium-232
C. Plutonium-239
D. None of these
ANS:- C

44) Solar energy results from __________ reaction.

A. fission
B. combustion
C. thermonuclear
D. none of these
ANS:- C

45) Heavy water (D2O) in a nuclear reactor serves as a

A. coolant
B. moderator
C. both (a) & (b)
D. neutron absorber
ANS:- C

46) Atoms of U-238 and U-235 differ in structure by three

A. electrons and three protons
B. protons
C. neutrons
D. electrons
ANS:- C

47) A radioactive isotope undergoes decay with respect to time following __________ law.

A. logarithmic
B. exponential
C. linear
D. inverse square
ANS:- B

48) Main source of __________ is monazite sand.

A. uranium
B. polonium
C. hafnium
D. thorium
ANS:- D

49) The first underground nuclear test was conducted by India at

A. Jaisalmer
B. Pokharan
C. Kalpakkam
D. Narora
ANS:- B

50) Which of the following is not a good moderating material?

A. Concrete
B. Boron
C. 18/8 stainless steel
D. All (a), (b) and (c)
ANS:- D

51) The molecular weight of heavy water is

A. 10
B. 18
C. 20
D. 36
ANS:- C

52) The size of an atom is of the order of one

A. Angstrom
B. fermi
C. micron
D. mm
ANS:- A

53) An ideal coolant for a nuclear reactor should

A. be a good absorber of neutrons.
B. be capable of attaining high temperature, only when it is pressurised.
C. have high density, but low heat transfer co-efficient.
D. be free from radiation damage and non-corrosive.
ANS:- D

54) The phenomenon of nuclear fission is opposite to that of

A. radioactive decay
B. thermionic emission
C. nuclear fusion
D. combustion
ANS:- C

55) A thermal nuclear reactor compared to a fast breeder reactor

A. uses slower neutrons for fission.
B. uses faster neutrons for fission.
C. gives higher power density.
D. requires less fuel to run at the same power level.
ANS:- A

56) Coolant used in a boiling water reactor is

A. hydrogen gas
B. water
C. steam
D. a mixture of water & steam
ANS:- D

57) Liquid metal (e.g, . molten sodium) is preferred as a coolant in case of a/an __________ reactor.

A. homogeneous
B. graphite moderated
C. fast breeder
D. enriched uranium (3% U-235) fuelled
ANS:- C

58) In a pressurised water reactor (PWR), the

A. fuel is natural uranium and heavy water acts both as moderator & coolant.
B. coolant water boils in the core of the reactor.
C. coolant water is pressurised to prevent bulk boiling of water in the core.
D. use of moderator is not required.
ANS:- C

59) Which of the following accounts for the maximum energy release in the nuclear fission process?

A. Kinetic energy of fission products
B. Radioactive decay of fission products
C. Instantaneous release of ?-rays
D. Kinetic energy of neutrons
ANS:- A

60) Which of the following nuclear reactors is the most efficient thermodynamically while operating between the same temperature and pressure limits of the reactor?

A. Molten sodium cooled
B. CO2 gas cooled
C. Pressurised water
D. Boiling water
ANS:- D

61) 75% of a radioactive element decays in 6 hours. Its half life period is __________ hours.

A. 3/4
B. 1/6
C. 3
D. 4
ANS:- C

62) The phenomenon of radioactivity was discovered by

A. Madam Curie
B. Bacquerrel
C. Roentgen
D. J.J. Thomson
ANS:- B

63) Out of the following places, heavy water plant is not located at

A. Baroda
B. Ramagundam
C. Talcher
D. Tuticorin
ANS:- B

64) A pressurised water reactor (PWR) uses pressurised water as a

A. coolant.
B. working fluid in power turbine.
C. moderator.
D. none of these.
ANS:- A

65) Pick out the correct statement.

A. Positron is the antiparticle of electron.
B. In a-decay, the ratio of neutron to proton decreases.
C. Ionising power of ß-rays is higher than that of a-rays.
D. Speed of a-rays is more than that of ?-rays.
ANS:- A

66) Which of the following is the best nuclear fuel?

A. Np- 239
B. U-234
C. Pu-239
D. Th-236
ANS:- C

67) Uranium is recovered from its ore (pitchblende) by

A. froth floatation technique.
B. leaching with sulphuric acid.
C. smelting in a furnace.
D. dissolving in water.
ANS:- B

68) Positron is a/an

A. nucleus having two protons.
B. helium nucleus.
C. electron with positive charge.
D. nucleus with one proton and one neutron.
ANS:- C

69) Which of the following is a fuel for a fusion reactor (thermonuclear reactor)?

A. Deuterium and tritium
B. U-233
C. Thorium
D. Heavy water
ANS:- A

70) Heavy water is used as a moderator in a

A. pressurised water reactor (PWR).
B. boiling water reactor (BWR).
C. Candu reactor.
D. molten sodium cooled reactor.
ANS:- C

71) Nuclear power plant is not located at

A. Talcher (Orissa)
B. Rawatbhata (Rajasthan)
C. Kalpakkam (Tamilnadu)
D. Kaiga (Karnataka)
ANS:- A

72) Isotopes of an element have the same

A. number of neutrons
B. mass number
C. electronic configuration
D. atomic weight
ANS:- C

73) Extraction of uranium from its ore is done by __________ method.

A. chemical
B. pyrometallurgical
C. physical beneficiation
D. electrometallurgical
ANS:- A

74) Radioactivity of an isotope is expressed in

A. barn
B. MeV
C. Curie
D. Ergs=
ANS:- C

75) A heterogeneous reactor is the one, in which the moderator and the

A. coolant are different materials.
B. coolant are present in different phases (e.g., heavy water and graphite).
C. fuel are present in different phases (e.g. uranium and heavy water).
D. none of these.
ANS:- C

76) The atomic mass of an element is fractional, because

A. of uncertainty principle.
B. it may have isobars.
C. it contains neutrons.
D. it may have isotopes.
ANS:- D

77) Net efficiency of ordinary light water cooled nuclear reactor is about __________ percent.

A. 32
B. 52
C. 72
D. 88
ANS:- A

78) The sum of masses of two nuclei produced in nuclear fission compared to the mass of original nucleus is

A. less
B. more
C. same
D. much more
ANS:- A

79) The new nucleus formed after ß-decay of a radioactive element has

A. less atomic number
B. less atomic weight
C. more atomic number
D. more atomic weight
ANS:- A

80) When the difference between mass number and atomic number of atoms of two or more elements are same, the atoms are termed as

A. isomers
B. isotopes
C. isobars
D. isotones
ANS:- D

81) ‘Heavy water’ is termed as ‘heavy’ because it is

A. denser than water.
B. an oxide of deuterium.
C. a heavy liquid.
D. an oxide of heavier isotope of oxygen.
ANS:- B

82) Uranium Corporation of India Limited (UCIL) engaged in the mining & concentration of uranium ore is located at

A. Alwaye (in Kerala)
B. Jadugoda (in Jharkhand)
C. Kalpakkam (in Tamilnadu)
D. Gopalpur coast (in Orissa)
ANS:- B

83) __________ gas is normally not used as a coolant in a nuclear reactor, because of its high neutron capture cross-section.

A. Nitrogen
B. Hydrogen
C. Helium
D. Carbon dioxide
ANS:- A
Is This Answer Correct? 0 Yes 1 No

84) Pick out the correct statement.

A. Loss of electrons from neutral atoms produces negative ions.
B. The radius of nucleus & atomic size are of the order of 10-12 cm & 10-8 cm respectively.
C. Gain of electrons by neutral atoms form cations.
D. Proton to neutron ratio in a stable nucleus is 2 : 1.
ANS:- B

85) Quantity of fissionable material (i.e. U-235) in natural uranium is __________ percent.

A. 0.71
B. 6.31
C. 99.29
D. 12.73
ANS:- A

86) Which of the following is present in Bhabha Atomic Research Centre (BARC) complex, Trombay (Bombay)?

A. Power reactor
B. Research reactor
C. Fast breeder reactor
D. Heavy water plant
ANS:- B

87) Which of the following isotopes is not present in natural uranium?

A. U-238
B. U-234
C. U-235
D. U-232
ANS:- D

88) Which of the following is not used as a moderator in nuclear reactor?

A. Molten sodium
B. Light water
C. Beryllium
D. Boron hydride
ANS:- A

89) Percentage of the heavy water in ordi water is around

A. 0.015
B. 7.54
C. 0.71
D. 32.97
ANS:- A

90) Water is a better coolant than a gas (like CO2, He, N2 etc.), because it

A. is a better neutron moderator as well.
B. requires comparatively smaller pumps and heat exchanger for a given heat transfer rate.
C. has a better heat transfer characteristics, and it can be pressurised to attain a high temperature.
D. all (a), (b) and (c).
ANS:- D

91) Pick out the wrong statement.

A. The disintegration rate of a radioactive substance can not be increased by heating it.
B. Electrons have negligible mass and unit negative change.
C. Deuterium atom has one proton and two neutrons in its nucleus.
D. Cadmium is capable of absorbing neutrons.
ANS:- C

92) Pressure in a Pressurised Water Reactor (PWR) is used for

A. maintaining constant pressure in the primary cooling circuit under varying loads.
B. superheating the steam.
C. pressurising the water in the primary coolant circuit.
D. none of these.
ANS:- A

93) Energy produced in the nuclear fission is of the order of __________ MeV.

A. 20
B. 200
C. 1000
D. 2000
ANS:- B

94) In ß-decay of radioactive material, the ratio of neutron to proton

A. increases.
B. remains same.
C. decreases.
D. is unpredictable; may increase or decrease.
ANS:- C

95) Nuclear fuel usually used in a Boiling Water Reactor (BWR) is

A. plutonium
B. enriched uranium
C. natural uranium
D. thorium
ANS:- B

96) Which is not a fissile nuclear material?

A. U-233
B. U-235
C. U-238
D. Pu-239
ANS:- C

97) Heavy water plant is not located at

A. Talcher
B. Tuticorin
C. Ramagundam
D. Kota
ANS:- C

98) Primary purpose of a __________ nuclear reactor is to supply a high neutron flux of the order of 1013 to 1014 neutrons/cm2 second.

A. research
B. power
C. breeder
D. homogeneous
ANS:- A

99) The critical mass of a fissionable material can be reduced by

A. heating it.
B. cooling it.
C. surrounding it by neutron reflecting material.
D. surrounding it by neutron absorbing material.
ANS:- C

100) Thorium-232 (a fertile material) on absorption of a neutron gets converted into __________ , which is a fissile material.

A. thorium-233
B. uranium-235
C. uranium-233
D. plutonium-239
ANS:- C

NUCLEAR ENGINEERING Interview Questions and Answers pdf ::

101) Pick out the wrong statement.

A. Isotopes have the same number of protons & electrons, but different number of neutrons.
B. Hydrogen has two isotopes.
C. In ordinary hydrogen, 1H1 and 1H2 are present in the ratio 6400:1.
D. none of these.
ANS:- B

102) Nucleus of 92U235 contains __________ protons.

A. 92
B. 235
C. 143
D. 325
ANS:- A
Is This Answer Correct? 1 Yes 0 No

103) Safety rods provided in nuclear reactors to guard against accidents, in case of earthquake are made of

A. high carbon steel.
B. molybdenum.
C. zircalloy.
D. boron or cadmium.
ANS:- D

104) Percentage of heavy water in ordinary water is around

A. 0.015
B. 7.54
C. 0.71
D. 32.97
ANS:- A

105) Which of the following undergoes fission reaction easily?

A. U-235
B. U-238
C. Th-232
D. none of these
ANS:- A

106) Pick out the wrong statement.

A. a-particle emission from a radioactive element makes it electrically negative.
B. ß-particle emission from a radioactive element makes it electrically positive.
C. A radioactive element having a half life period of 20 years will completely disintegrated in 40 years.
D. The disintegration constant of a radioactive isotope is independent of pressure, temperature or concentration.
ANS:- C

107) One ‘amu’ is equivalent to

A. 9.31 Mev
B. 931 eV
C. 931 MeV
D. 931 J
ANS:- C

108) Unit of radioactivity is

A. barn
B. Fermi
C. Angstrom
D. Curie
ANS:- D

109) The half life period of a radioactive element depends upon the

A. temperature
B. pressure
C. amount of element present
D. none of these
ANS:- D

110) Indian monazite sand contains __________ percent thorium.

A. 10
B. 25
C. 60
D. 90
ANS:- A

111) A radioactive substance does not emit

A. a-ray
B. proton
C. position
D. ß-ray
ANS:- B

112) Out of the following, nucleus of __________ atom contains the largest number of neutrons.

A. U-235
B. U-238
C. U-239
D. Pu-239
ANS:- C

113) ß-rays emission in radioactive disintegration is always accompanied by the emission of

A. ?-rays
B. a-rays
C. neutrons
D. none of these
ANS:- A

114) Heavy water plant is not located at

A. Kota and Baroda
B. Talcher (Orissa)
C. Tuticorin(Tamilnadu)
D. Korba
ANS:- D
Is This Answer Correct? 1 Yes 0 No

115) Nuclear power generation capacity in India is

A. 3000 MW.
B. 10000 MW.
C. more than hydroelectric power generation capacity.
D. more than thermal power generation capacity.
ANS:- A

116) Both tritium and deuterium have the same number of

A. neutrons
B. electrons
C. protons
D. nucleons
ANS:- A

117) Hydrogen differs from deuterium in __________ properties.

A. radioactive
B. physical
C. chemical
D. all (a), (b) and (c)
ANS:- B

118) Which of the following radiations is the least penetrating?

A. a-rays
B. ß-rays
C. ?-rays
D. X-rays
ANS:- A

119) The radioisotope used to study the thyroid gland is

A. iodine
B. cobalt
C. iron
D. carbon
ANS:- A

120) Enriched uranium means that, it contains

A. more than 0.71% of U-235.
B. only fertile material.
C. only fissile material.
D. no impurities.
ANS:- A

121) In a homogeneous nuclear reactor, the __________ are mixed together.

A. fuel & coolant
B. fuel & moderator
C. coolant & moderator
D. none of these
ANS:- B

122) Artificially produced radioactive isotopes are used for

A. power generation.
B. treatment of certain diseases.
C. initiating nuclear fission and fusion.
D. all (a), (b) and (c).
ANS:- B

123) Uranium percentage in monazite sand is about

A. 0.01
B. 0.25
C. 1.2
D. 7
ANS:- B

124) Which of the following reactors is operated at high neutron flux and low power level?

A. Breeder reactor.
B. Research reactor.
C. Heterogeneous reactor.
D. Liquid metal (e.g., molten sodium) cooled reactor.
ANS:- B

125) Uranium ore is mined & concentrated in India at

A. Jadugoda(Jharkhand)
B. Kota (Rajasthan)
C. Tuticorin (Tamilnadu)
D. Talchar (Orissa)
ANS:- A

126) Ceramic nuclear metals compared to solid nuclear metals have

A. higher melting points.
B. low strength at high temperature.
C. more chances of radiation damage.
D. poorer corrosion resistance.
ANS:- A

127) Heavy water has maximum density at __________ C.

A. 4
B. 11.6
C. 0
D. 18.6
ANS:- B

128) A fast breeder reactor

A. uses natural uranium as fuel.
B. does not require a moderator.
C. both (a) and (b).
D. neither (a) nor (b).
ANS:- B

129) Which of the following factors is the most important in the site selection for a nuclear power plant?

A. Absence of earthquake prone zone in nearby areas.
B. Abundant availability of water.
C. Remotely located from residential areas.
D. Proximity to fuel source.
ANS:- A

130) Radioactive decay of a material involves a __________ order reaction.

A. third
B. second
C. first
D. zero
ANS:- C

131) Nuclear reactors are provided with shield to guard against the emission of mainly __________ rays.

A. X
B. a and ß
C. neutrons & gamma
D. infrared
ANS:- C

132) Isotopes of an element have different

A. mass number
B. electronic configuration
C. nuclear charge
D. chemical properties
ANS:- A

133) Biological shield is provided in a nuclear power reactor to protect the __________ from radiation damage.

A. fuel elements
B. operating personnels
C. walls of the reactor
D. none of these
ANS:- B

134) Mass of a positron is same as that of a/an

A. electron
B. a-particle
C. proton
D. neutron
ANS:- A

135) The mass number of an element is equal to the number of __________ in the nucleus.

A. electrons
B. neutrons
C. protons
D. neutrons plus protons (i.e., nucleons)
ANS:- D

136) In the gaseous diffusion process of uranium enrichment, the natural uranium is converted into gaseous

A. uranium oxide
B. uranium hexaflouride
C. uranium carbide
D. uranium sulphate
ANS:- B

137) Fast breeder test reactor at Kalpakkam is designed for using

A. thorium as a fertile material.
B. U-238 as a fertile material.
C. helium as a coolant.
D. uranium ore directly as a fuel.
ANS:- A

138) Fuel for a fast breeder reactor is

A. plutonium
B. uranium
C. radium
D. neptunium
ANS:- A

139) Number of secondary neutron emitted on fission of an atom of U-235 by slow neutron bombardment is

A. 3
B. 235
C. 200
D. 92
ANS:- A

140) A control rod

A. should have small absorption cross-section.
B. is generally made of boron, hafnium or cadmium.
C. should have large absorption cross-section.
D. both (b) and (c).
ANS:- D

141) Plutonium

A. is recovered from spent fuel from thermal nuclear reactor.
B. has much lower melting point (640C ) compared to thorium (1690C).
C. both (a) and (b).
D. neither (a) nor (b).
ANS:- C

142) A fast breeder reactor employs

A. graphite as moderator.
B. water as coolant.
C. molten sodium as coolant as well as moderator.
D. U-235 as fuel.
ANS:- D
Is This Answer Correct? 0 Yes 1 No

143) Fuel for a nuclear reactor (thermal) is

A. uranium
B. plutonium
C. radium
D. none of these
ANS:- A

144) Percentage of U-238 in natural uranium is around

A. 0.71
B. 99.29
C. 0.015
D. 29.71
ANS:- B

145) Emission of ß-particles during radioactive decay of a substance is from

A. innermost shell
B. nucleus
C. outermost shell
D. none of these
ANS:- B

146) How many atoms are present in one gm-atom of an element?

A. 2 x 10 23
B. 6 x 10 23
C. 6 x 10 32
D. 5 x 10 5
ANS:- B

147) Uranium ore is currently mined & concentrated at

A. Jadugoda
B. Ghatsila
C. Khetri
D. Alwaye
ANS:- A

148) Which of the following ores contains maximum percentage of uranium?

A. Carnotite
B. Thorium.
C. Rescolite
D. Pitchblende
ANS:- D

149) Atoms with same number of neutrons, but different number of nucleons are called

A. isotones
B. isobars
C. isotopes
D. isoters
ANS:- A

150) Enrichment of uranium is done to increase the concentration of __________ in the natural uranium.

A. U-238
B. U-233
C. U-235
D. Pu-239
ANS:- C

151) Thorium metal

A. resembles steel in appearance.
B. is less hard (in the range of silver).
C. is highly ductile.
D. all (a), (b) and (c).
ANS:- D

152) Fast breeder nuclear reactors using enriched uranium as fuel may contain upto a maximum of __________ percent of U-235 (i.e. fissile material).

A. 15
B. 45
C. 65
D. 85
ANS:- D

153) A fertile material is the one, which can be

A. converted into fissile material on absorption of neutron.
B. fissioned by slow (thermal) neutrons.
C. fissioned by fast neutrons.
D. fissioned by either slow or fast neutrons.
ANS:- A

154) Nuclides having the same atomic numbers are termed as

A. isotopes
B. isomers
C. isotones
D. isobars
ANS:- B

155) The most commonly used nuclear fuel in boiling water reactor is

A. enriched uranium
B. natural uranium
C. plutonium
D. monazite sand
ANS:- A

156) Which one is radioactive in nature?

A. Helium
B. Deuterium
C. Heavy hydrogen
D. Tritium
ANS:- D

157) __________ have the same mass number, but different nuclear charge.

A. Isotopes
B. Isobars
C. Isotones
D. none of these
ANS:- B

158) The half life period of a radioactive element depends on its

A. temperature
B. pressure
C. amount
D. none of these
ANS:- D

159) Graphite is used in nuclear reactor as

A. insulation lining of the reactor.
B. fuel.
C. lubricant.
D. retarder of neutron velocity.
ANS:- D
Is This Answer Correct? 1 Yes 0 No

160) The half life period of a radioactive substance is best determined by counting the number of alpha particles emitted per second in a Geiger Muller counter from its known quantity. If the half life period of a radioactive substance is one month, then

A. 3/4th of it will disintegrate in two months.
B. it will completely disintegrate in two months.
C. it will completely disintegrate in four months.
D. l/8th of it will remain intact at the end of four months.
ANS:- B
Is This Answer Correct? 1 Yes 0 No

161) Thermal shield is used in high powered nuclear reactors to

A. protect the walls of the reactor from radiation damage.
B. absorb the fast neutrons.
C. slow down the secondary neutrons.
D. protect the fuel element from coming in contact with the coolant.
ANS:- A
Is This Answer Correct? 1 Yes 0 No

162) The velocity of thermal (slow) neutrons triggering nuclear fission reaction (having energy equal to 0.025 eV) is about __________ metres/second.

A. 1100
B. 2200
C. 3300
D. 4400
ANS:- B
Is This Answer Correct? 1 Yes 0 No

163) _________ moderator is used in a fast breeder reactor.

A. Graphite
B. Heavy water
C. Beryllium
D. No
ANS:- D
Is This Answer Correct? 2 Yes 0 No

164) Which one is different for the neutral atoms of the isotopes of an element?

A. Atomic weights
B. Atomic numbers
C. Number of protons
D. Number of electrons
ANS:- A
Is This Answer Correct? 1 Yes 0 No

165) The ratio of atomic radius to its nuclear radius is about

A. 105
B. 108
C. 1012
D. 1015
ANS:- A
Is This Answer Correct? 1 Yes 0 No

166) The time required for half of the __________ of a radioactive isotope to decay is called its half life.

A. nuclei
B. electrons
C. protons
D. neutrons
ANS:- A

167) Which is a fertile nuclear fuel?

A. U-233
B. U-235
C. Pu-239
D. Th-232
ANS:- D

168) Nuclear fuel generally used in reactors is uranium oxide instead of uranium, because the former has higher

A. melting point, hence can be subjected to higher temperature.
B. density ; hence core volume for a given power output would be smaller.
C. resistance to effects of irradiation.
D. all (a), (b) and (c).
ANS:- D

169) Thorium can be converted into U-233 in a __________ reactor.

A. liquid metal cooled
B. fast breeder
C. thermal
D. swimming pool
ANS:- B

170) A moderator __________ the neutrons.

A. slows down
B. absorbs
C. accelerates
D. reflects
ANS:- A

171) Nuclear fuel complex, Hyderabad is engaged in the job of

A. manufacture of nuclear fuel elements/assemblies .
B. processing of uranium ore.
C. treatment of spent fuel.
D. none of these.
ANS:- A

172) Radioactive decay is a __________ change.

A. chemical
B. nuclear
C. physical
D. none of these
ANS:- B

173) __________ nuclear reactor does not require a heat exchanger to supply steam to power turbine.

A. Molten sodium cooled
B. Helium cooled
C. Boiling water
D. Pressurised water
ANS:- C

174) If 4 gm of a radioisotope has a half life period of 10 days, the half life of 2 gm of the same istotope will be __________ days.

A. 5
B. 10
C. 20
D. 30
ANS:- B

175) Pick out the wrong statement.

A. The nucleus of a hydrogen atom is identical with a proton.
B. A, ß-ray particle is identical with an electron.
C. Mass of an electron is about 1/1800th of the lightest nucleus.
D. Positron is heavier than a proton.
ANS:- D

176) Specific gravity of uranium and plutonium is about

A. 9
B. 13
C. 19
D. 27
ANS:- C

177) The function of moderators in nuclear reactor is to

A. slow down the secondary neutrons.
B. absorb the secondary neutrons.
C. control the chain reaction.
D. none of these.
ANS:- A

178) Which of the following is not used as a nuclear fuel cladding material?

A. Zircalloy
B. Cadmium
C. Ceramics
D. Stainless steel
ANS:- B

179) The atomic weight and atomic number of an element are A and Z respectively. What is the number of neutrons in the atom of that element?

A. A+Z
B. A- Z
C. A
D. Z
ANS:- B

180) Thermal nuclear reactors using enriched uranium as fuel contains a maximum of __________ percent fissile material i.e. U-235.

A. 1
B. 2
C. 3
D. 7
ANS:- C

181) Which of the following types of nuclear reactors is most prone to radioactive hazards?

A. Pressurised water reactor
B. Gas cooled reactor
C. Molten sodium cooled reactor
D. Boiling water reactor
ANS:- D

182) Thermal neutrons which are used to cause the fission of U-235 have energy __________ eV.

A. < 0.025 B. > 1
C. 1-25
D. > 200.
ANS:- A

183) Out of the following places, a nuclear power plant is not located at

A. Talcher (Orissa)
B. Kaiga (Karnataka)
C. Rawatbhata (Rajsthan)
D. Kalpakkam (Tamilnadu)
ANS:- A

184) Research reactors are normally meant for

A. producing high neutron flux 1012-1013 neutrons/cm2, sec and studying the effect of neutron bombardment on dif ferent materials.
B. accelerating the neutrons.
C. power generation.
D. none of these
ANS:- A

185) The ratio of volume of an atom to that of its nucleus is

A. 1012
B. 10-12
C. 10-8
D. 108
ANS:- A

186) Sodium melts (at atmospheric pressure) at a temperature of __________ C.

A. 58
B. 98
C. 348
D. 588
ANS:- B

187) Hydrogen bomb employs the nuclear fusion of

A. hydrogen
B. deuterium
C. tritium
D. helium
ANS:- B

188) The largest stable nucleus is

A. U-235
B. U-238
C. Pb-206
D. Bi-209
ANS:- A

189) In a nuclear explosion, the energy is released primarily in the form of __________ energy-

A. potential
B. thermal
C. kinetic
D. electrical
ANS:- C

190) Tarapur atomic power station

A. has two boiling water reactors of American design.
B. has an installed capacity of 400 MW.
C. is the first power reactor in India, which became critical in 1969.
D. all (a), (b) and (c).
ANS:- D

191) Fast breeder Test Reactor (FBTR) is located at

A. Kalpakkam (near Madras).
B. Kota (in Rajasthan).
C. BARC (Trombay).
D. Tarapur (in Maharashtra).
ANS:- A

192) The type of pump used for the recirculation of molten sodium coolant in liquid metal cooled reactor is a/an __________ pump.

A. electromagnetic
B. reciprocating
C. centrifugal
D. volute
ANS:- A

193) “Critical mass” is the minimum mass of nuclear fissile material required for the

A. sustainment of chain reaction.
B. power generation on commercial scale.
C. economic power generation.
D. none of these.
ANS:- A

194) Energy equivlant to one atomic mass unit (amu) is __________ MeV.

A. 9.31
B. 93.1
C. 931
D. 9310
ANS:- C

195) Velocity of the thermal neutron (< 0.025 eV) used for fission of U-235 is around __________ m/sec.

A. 1
B. 2200
C. 3 x 1011
D. 9 x 1021
ANS:- B

196) MeV is the unit of

A. radioactivity
B. energy
C. potential difference
D. none of these
ANS:- B

197) Hydrogen has __________ isotopes.

A. no
B. one
C. two
D. three
ANS:- D

198) A homogeneous reactor is the one, in which the

A. fissile atoms are evenly distributed throughout the mass of nuclear reactor.
B. same substance (e.g. heavy water) is used as moderator & coolant.
C. the fuel and the moderator is mixed to form a homogeneous material.
D. all (a), (b) and (c).
ANS:- C

199) Which one is the radioactive isotope of hydrogen?

A. Deuterium
B. Ortho-hydrogen
C. Tritium
D. None of these
ANS:- C

200) Final product of uranium extraction plant at Jadugoda (Bihar) is

A. uranium
B. uranium oxide
C. uranium carbide
D. magnesium diuranate
ANS:- D

201) Molten sodium (as a coolant in fast breeder reactor)

A. can’t attain high temperature at normal pressure.
B. is not at all corrosive, even at a higher temperature.
C. is highly radioactive at elevated temperatures and can cause explosion, when it comes in contact with air or water.
D. none of these
ANS:- C

202) Which of the following is not, a fertile material?

A. Th-232
B. U-238
C. U-233
D. none of these
ANS:- C

203) The atomic number of an element is equal to the number of __________ present in its atom.

A. neutrons
B. electrons
C. protons
D. either (b) or (c)
ANS:- D

204) Which of the following is a moderating material used in nuclear reactor ?

A. Graphite.
B. Cadmium.
C. Zircalloy (an alloy of zirconium and aluminium).
D. Stainless steel.
ANS:- A

205) A nuclear reactor can’t be used for

A. the production of radioisotopes.
B. supplying intense fields or beams of neutron for scientific experiments.
C. marine ship propulsion.
D. none of these.
ANS:- D

206) Fission of U-235 on slow neutron bombardment can be represented by

A. 92U235 + 3 ?1 56Ba143 + 36Kr90
B. 92U235 + 0n1 56Ba143 + 36Kr90 + 3 0n1
C. 92U235 + 0n1 56Ba143 + 36Kr90 + 3 0n1 + Q (energy)
D. 92U235 + 0n1 92U236 + 30n1+ Q (energy)
ANS:- C

207) The atomic number of a radioactive element is not changed, when it emits __________ rays.

A. a
B. ß
C. ?
D. a & ß
ANS:- C

208) Ordinary water is not used as a moderator because, it

A. has a low absorption cross-section.
B. has a low scattering cross-section.
C. absorbs neutrons.
D. does not absorb neutrons.
ANS:- C

209) Moderating material used in a thermal-reactor should be a

A. good absorber of neutrons.
B. solid substance.
C. poor absorber of neutrons.
D. none of these.
ANS:- C

210) Which is used as a coolant in nuclear reactor due to its high capture cross-section ?

A. H2
B. N2
C. He
D. CO2
ANS:- A

211) A boiling water reactor is the one, in which the

A. coolant water is allowed to boil in the core of the reactor.
B. coolant water, after being heated in the reactor core, generates steam in a boiler.
C. pressurised water is pumped into the core.
D. fuel and the coolant are thoroughly mixed to form a homogeneous solution.
ANS:- A

212) Spent fuel from the nuclear thermal reactor contains

A. fission products
B. plutonium
C. unused fuel
D. all (a), (b) & (c)
ANS:- D

213) Which of the following may not need a control rod ?

A. Liquid metal cooled reactor.
B. Fast breeder reactor.
C. Candu reactor.
D. None of these.
ANS:- D

214) Thorium-232 is converted into uranium-233 in a/an __________ nuclear reactor.

A. thermal
B. fast breeder
C. heavy water moderated
D. enriched uranium
ANS:- B

215) Fast breeder reactors do not

A. use Th-232 as fissile fuel.
B. convert fertile material to fissile material.
C. use fast neutrons for fission.
D. use molten sodium as coolant.
ANS:- A

216) One ‘amu’ is equivalent to

A. 9.31 MeV
B. 931 eV
C. 931 Mev
D. 931J
ANS:- C

217) Commercial power generation from fusion reactor is not yet possible, because

A. it is difficult to control fusion reaction.
B. the fuel required (e.g. deuterium and tritium) is scarce.
C. it is difficult to initiate fusion reaction.
D. quantity of fuel required for initiating fusion reaction is prohibitively high.
ANS:- A

218) The amount of a radioisotope remaining undecayed after a time equal to four times its half life, will be __________ percent.

A. 3.125
B. 6.25
C. 12.50
D. 25
ANS:- B

219) Which of the following may not need a moderator?

A. Candu reactor
B. Fast breeder reactor
C. Homogeneous reactor
D. Pressurised water reactor
ANS:- B

220) The time taken for a radioactive element to reduce to 50% of its original weight is __________ years, if its half life period is 12 years.

A. 24
B. 18
C. 6
D. 36
ANS:- B
Is This Answer Correct? 1 Yes 0 No

221) Heat is generated in a nuclear reactor (thermal) by

A. combustion of a nuclear fuel e.g. uranium.
B. fusion of atoms of uranium.
C. absorption of neutrons in uranium atoms.
D. fission of U-235 by neutrons.?
ANS:- D
Is This Answer Correct? 1 Yes 0 No

222) The decay product of tritium (a beta emitter) is

A. lithium
B. helium
C. deuterium
D. hydrogen?
ANS:- B
Is This Answer Correct? 1 Yes 0 No

223) Gas cooling as compared to water cooling of nuclear reactors

A. can not attain a high temperature.
B. is more efficient as gas has a higher specific heat.
C. can produce only saturated steam for feeding to power turbine.
D. none of these.
ANS:- D

224) Which of the following is artificially produced as it does not occur in nature ?

A. Uranium-235
B. Uranium-233
C. Plutonium-239
D. Both (b) and (c)
ANS:- D

225) The second underground nuclear test was conducted by India at

A. Jaisalmer
B. Pokhran
C. Kalpakkan
D. Narora
ANS:- B

226) The amount of a radioactive material (having a half life of 100 years) remaining after 400 years will be __________ of its original weight.

A. 1/2
B. 1/4
C. 1/8
D. 1/16
ANS:- D

227) Which is the most commonly used molten metal for cooling of nuclear reactors ?

A. Calcium
B. Sodium
C. Mercury
D. Zinc
ANS:- B

228) An electron has a mass that is approximately __________ that of the proton.

A. 1836 (approximately)
B. 1/1836 (approximately)
C. 1
D. 8?
ANS:- B

229) Which of the following is not a naturally occurring nuclear fuel

A. Uranium-238
B. Thorium-233
C. Plutonium-239
D. None of these
ANS:- C

230) The mass number of an element is not changed, when it emits __________ radiations.

A. a & ß
B. ß & ?
C. ? & a
D. a, ß, & ??
ANS:- B

231) The decrease in the atomic number is not observed in case of

A. electron capture
B. ß-emission
C. a-emission
D. positron emission?
ANS:- B

232) Which of the following may be used to measure the rate of nuclear disintegration?

A. Geiger-Muller Counter
B. Cyclotron
C. Cold chamber
D. Mass spectrograph?
ANS:- A

233) What is the history of Nuclear Engineering?
Nuclear engineering was born in the 20th century with the announcement in 1939 of the discovery of nuclear fission by the German chemists.

234) Do you know what does a nuclear engineer do?
Developing nuclear equipment, such as reactor cores and radiation shielding
Monitoring nuclear plant design, construction and operations to ensure that the plants meet safety standards
Writing instructions for the handling and disposal of nuclear waste
Testing whether methods of using nuclear material, reclaiming nuclear fuel or disposing of nuclear waste are acceptable
Taking corrective action or ordering plant shutdowns in emergencies
Examining nuclear accidents and gathering data that can be used to prevent future accidents

235) Do you know what is Nuclear Engineering?
Nuclear engineering is the branch of engineering concerned with the application of the breakdown (fission) as well as the fusion of atomic nuclei and/or the application of other sub-atomic physics, based on the principles of nuclear physics.

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