The predominant isotope of the naturally occuring element is
U₂₃₅
U₂₃₈
Pu₂₃₃
Pu₂₃₉
Correct Answer :
B. U₂₃₈
Related Questions
The control rods in the control system of nuclear reactors are used to
Absorb excess neutrons
Control fuel consumption
Control temperature
All of these
The commonly used material for shielding is
Lead or concrete
Lead and tin
Graphite or cadmium
Thick galvanised sheets
The process by which a heavy nucleus is spitted into two light nuclei is known as
Splitting
Fission
Fusion
Disintegration
A moderator, apart from its high neutron slowing power, and low non-productive neutron, should be
Stable under nuclear radiation
Corrosion resistant
Good thermal conductor
All of these
In triggering fission, the following types of neutrons are desirable
Fast moving
Slow moving
Critical neutrons
Neutrons at rest
Boiling water reactor uses the following as moderator, coolant and working fluid
Ordinary fluid
Heavy water
Molten lead
Hydrogen gas
The efficiency of a nuclear power plant in comparison to a conventional thermal power plant is
Same
More
Less
May be less or mote depending on size
For economical operation of a nuclear plant
Used fuel should be reprocessed
Moderator should be used
Coolant should be employed
Control rods should be used
The nuclear radiators produced in a reactor which must be shielded are
Electrons
α, β and γ rays
Neutron and gamma rays
None of these
Which of the following nuclear reactor does not need a heat exchanger for generation of steam?
Gas cooled
Liquid metal cooled
Pressurised water
Boiling water
A nuclear reactor is said to be critical when the neutron population in the reactor core is
Rapidly increasing leading to the point of explosion
Decreasing from the specified value
Reduced to zero
Constant
Which of the following are ferrite materials?
U₂₃₃ and Pu₂₃₉
U
U₂₃₈ and Pu₂₃₉
U₂₃₈ and Th₂₃₉
Natural uranium is made up of
99.282% U₂₃₈, 0.712% U₂₃₅, 0.006% U₂₃₄
99.282% U₂₃₅, 0.712% U₂₃₈, 0.06%' U₂₃₄
99.282% U₂₃₄, 0.712% U₂₃₈, 0.006% U₂₃₅
99.282% U₂₃₅, 0.712% U₂₃₄, 0.006% U₂₃₈
A pressurised water reactor employs pressurises for the following application
To maintain constant pressure in primary circuit under varying load
To Supply high pressure steam
To increase pressure of water in primary circuit
To provide sub cooled water at high pressure
Electron volt is the unit of
Atomic power
Energy
Voltage
Radio activity
Enriched uranium may contain fissionable contents of the order of
1-99 %
1-25 %
1-50 %
1-75 %
Fast breeder reactor uses
Boiler
Direct cycle of coolant system
Double circuit system of coolant cycle
Multi passes system
Which of the following is the primary fuel?
U₂₃₃
U
U₂₃₈
Pu
The secondary fuel used in nuclear power plants is
U₂₃₃ and Pu₂₃₉
U₂₃₅ and Th₂₃₂
U₂₃₅ and Pu₂₃₈
U₂₃₃ and Pu₂₃₈
A nuclear fission produces energy of following order in MeV
20
200
2000
20,000
Enriched uranium is required as a fuel in a nuclear reactor, if light water is used as moderator and coolant, because light water has
High neutron absorption cross-section
Low moderating efficiency
High neutron scatter cross-section
Low neutron absorption cross-section
In a fission process, maximum percentage of energy is released as
Kinetic energy of neutrons
Kinetic energy of fission products
Instantaneous release of gamma rays
Gradual radioactive decay of fission products
Effective moderators are those materials which contain
Light weight atoms
Heavy weight atoms
Critical atoms
Zero weight atoms
Each fission of U₂₃₅ produces on the average _________ fast neutrons as a product of reaction.
2.46
24.6
246
2460
The main interest of shielding in nuclear reactor is protection against
X-rays
Infrared rays
Neutrons and gamma rays
Electrons
Enriched uranium is one in which
Percentage of U₂₃₅ has been artificially increased
Percentage of U has been artificially increased
Percentage of U₂₃₄ has been artificially increased
Extra energy is pumped from outside
Plutonium is produced
As basic raw material
By neutron irradiation of Uz
By neutron irradiation of thorium
Artificially
U235 will undergo fission by
High energy (fast) neutrons alone
Low energy (slow) neutrons alone
Either fast or slow neutrons
Medium energy neutrons
Artificial radioactive isotopes find application in
Power generation
Nucleonic devices
Nuclear fission
Medical field
Reactors designed for propulsion applications are designed for
Natural uranium
Enriched uranium
Pure uranium
Any type of uranium