A. Highly purified water
B. A compound of oxygen and deuterium
C. Water having dissolved salts of heavy metals
D. None of these
Related Mcqs:
- The number of neutrons accompanying the formation of 54Xe139 and 38Sr94 from the absorption of a slow neutron by 92U235, followed by nuclear fission is __________________?
A. 1
B. 2
C. 3
D. 4 - 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 - Heavy water (D2O) in a nuclear reactor serves as a_______________?
A. Coolant
B. Moderator
C. Both A. & B.
D. Neutron absorber - 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 - 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 - 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 - 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 - Nuclear reactors are provided with shield to guard against the emission of mainly _____________ rays?
A. X
B. α and β
C. Neutrons & gamma
D. Infrared - 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 - 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.
