50. Natural uranium is made up of
A.99.282% U238, 0.712% U235, 0.006% U234
B.99.282% U235, 0.712% U238, 0.06% U234
C.99.282% U234, 0.712% U238, 0.006% U235
D.99.282% U235, 0.712% U234, 0.006% U238

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51. In order to have constant chain reaction to produce a constant rate of heat output, the value of ratio of the number of neutrons in one generation to the number of neutrons in the immediately preceding generation must be
A.Greater than 1.0
B.Less than 1 0
C.Equal to zero
D.Equal to 1.0

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52. Fast breeder reactor uses
A.Boiler
B.Direct cycle of coolant system
C.Double circuit system of coolant cycle
D.Multi pass system

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53. Plutonium is produced
A.As basic raw material
B.By neutron irradiation of U238
C.By neutron irradiation of thorium
D.Artificially

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54. Pressurised water reactor is designed
A.For boiling water in the core
B.To use liquid sodium metal as coolant
C.To use intermediate coolant
D.To prevent the water coolant from boiling in the core

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55. The coolant used in boiling water reactor is
A.CO2
B.Mixture of water and steam
C.Liquid metal
D.Mercury

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56. Which of the following is the heaviest
A.Neutron
B.Proton
C.Atom
D.Electron

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