Where reactor operation is designed with fast neutrons such as in reactors using highly enriched fuel, the moderator used is
Heavy water
Graphite
Carbon dioxide
No moderator is needed
Correct Answer :
D. No moderator is needed
Related Questions
Gas cooled reactor uses following materials as moderator, and coolant
Graphite, CO2
Graphite, air
Heavy water, CO2
Lead, H2
The commonly used material for shielding is
Lead or concrete
Lead and tin
Graphite or cadmium
Thick galvanised sheets
A fission chain reaction in uranium can be developed by
Slowing down fast neutrons so that Uz fission continues by slow motion neutrons
Accelerating fast neutrons
Absorbing all neutrons
Using moderator
Boiling water reactor employs
Boiler
Direct cycle of coolant system
Double circuit system of coolant cycle
Multi passes system
The control rods in the control system of nuclear reactors are used to
Absorb excess neutrons
Control fuel consumption
Control temperature
All of these
A fast breeder reactor
Uses graphite rods as moderator
Has powerful moderator
Has no moderator
Uses ferrite material as moderator
The main interest of shielding in nuclear reactor is protection against
X-rays
Infrared rays
Neutrons and gamma rays
Electrons
Which of the following is more appropriate for a moderator? One which
Does not absorb neutrons
Absorbs neutrons
Accelerates neutrons
Eats up neutrons
Artificial radioactive isotopes find application in
Power generation
Nucleonic devices
Nuclear fission
Medical field
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
Reactors for propulsion applications use
Natural uranium
Molten lead
Any form of uranium
Thorium
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
Where reactor operation is designed with fast neutrons such as in reactors using highly enriched fuel, the moderator used is
Heavy water
Graphite
Carbon dioxide
No moderator is needed
A fast breeder reactor uses
90% U₂₃₅
U₂₃₈
U₂₃₅
Pu₂₃₉
Which of the following is the heaviest?
Neutron
Proton
Atom
Electron
U233 is produced
As basic raw material
By neutron irradiation of Uz
By neutron irradiation of thorium
Artificially
Reactors for propulsion applications are designed for
Any form of uranium
Natural uranium
Enriched uranium
Plutonium
A nuclear fission produces energy of following order in MeV
20
200
2000
20,000
The risk of radioactive hazard is greatest in the turbine with following reactor
Pressurised water
Boiling water
Gas cooled
Liquid metal cooled
The unit of radioactivity is
Electron volt
Electron ampere
Curie
MV
Ideally the neutron flux in reactor should be
Maximum in centre and zero at side
Maximum at side and zero in canter
Uniform throughout
Zero throughout
U238 will undergo fission by
High energy (fast) neutrons alone
Low energy (slow) neutrons alone
Either fast or slow neutrons
Medium energy neutrons
A moderator, in nuclear power plants, is a medium introduced into the fuel mass in order to
Slow down the speed of fast moving neutrons
Control the reaction
Reduce the temperature
Extracts heat from nuclear reaction
Plutonium is produced
As basic raw material
By neutron irradiation of Uz
By neutron irradiation of thorium
Artificially
Moderator in nuclear plants is used to
Reduce temperature
Extract heat from nuclear reaction
Control the reaction
Cause collision with the fast moving neutrons to reduce their speed
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
Amongst the following, the fissionable materials are
U₂₃₃ and Pu₂₂₉
U₂₃₁ and Pu₂₃₃
U₂₃₅ and Pu₂₃₅
U₂₃₈ and Pu₂₃₉
Hydrogen is preferred as better coolant in comparison to CO₂ because former
Is lighter
Is inert
Has high specific heat
Is a good conductor
The fast breeder reactor uses the following moderator
Demineralised water
Carbon dioxide
Heavy water
No moderator is used
Breeder reactor has a conversion ratio of
Unity
More than unity
Less than unity
Zero