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
Correct Answer :
A. Slow down the speed of fast moving neutrons
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
Which of the following statement is correct regarding the features of a Breeder reactor?
It produces more fuel than it consumes.
It requires highly enriched fuel.
It requires liquid sodium metal as moderator.
All of the above
Reflector in nuclear power plants _________ neutron leakage.
Increases
Decreases
Have no effect on
None of these
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
The primary fuel used in nuclear power plants is
U₂₃₅
U₂₃₈
Pu₂₃₉
Pu₂₃₃
The function of control rods in nuclear plants is to
Control temperature
Control radioactive pollution
Control absorption of neutron
Control fuel consumption
Nuclear reactors are used
To produce heat for thermoelectric power
To produce fissionable material
To propel ships, submarines, aircrafts
All of these
The unit of radioactivity is
Electron volt
Electron ampere
Curie
MV
A nuclear fission is initiated when the critical energy as compared to neutron binding energy of the atoms is
Same
More
Less
There is no such criterion
A fast breeder reactor
Uses graphite rods as moderator
Has powerful moderator
Has no moderator
Uses ferrite material as moderator
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
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
Superheated steam is generated in following reactor
Boiling water
Gas cooled
Pressurised water
All of the above
Each fission of U₂₃₅ produces on the average _________ fast neutrons as a product of reaction.
2.46
24.6
246
2460
One gram of uranium will produce energy equivalent to approximately
1 tonne of high grade coal
4.5 tonnes of high grade coal
10 tonnes of high grade coal
100 tonnes of high grade coal
In natural uranium, the constituents of three naturally occuring isotopes are
U₂₃₄ = 0.006%, U₂₃₅ = 0.712% and U₂₃₈ = 99.282%
U₂₃₄ = 0.712%, U₂₃₅ = 0.006% and U₂₃₈ = 99.282%
U₂₃₄ = 99.282%, U₂₃₅ = 0.006% and U₂₃₈ = 0.712%
U₂₃₄ = 0.006%, U₂₃₅ = 99.282% and U₂₃₈ = 0.712%
Reactors for propulsion applications use
Natural uranium
Molten lead
Any form of uranium
Thorium
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
Uranium has isotopes
U₂₃₄
U₂₃₅
U₂₃₈
All of these
The fast breeder reactor uses the following moderator
Demineralised water
Carbon dioxide
Heavy water
No moderator is used
Boiling water reactor uses the following as moderator, coolant and working fluid
Ordinary fluid
Heavy water
Molten lead
Hydrogen gas
The energy produced by a thermal reactor of same size as a breeder reactor is
Almost same
Slightly more
Slightly less
Much less
The predominant isotope of the naturally occuring element is
U₂₃₅
U₂₃₈
Pu₂₃₃
Pu₂₃₉
The mass number of a substance represents the sum of total number of
Protons and neutrons in an atom
Protons and electrons in an atom
Neutrons and electrons in an atom
Protons and neutrons in a nucleus
The coolant used in boiling water reactor is
CO2
Pressurised water
Mixture of water and steam
Liquid metal
Pick up the wrong statement fast breeder reactors
Operate at extremely high power densities.
Are liquid metal cooled
Produce more fuel than they consume
Use water as coolant
The nuclear energy is measured as
MeV
Curie
Farads
MW
Which of the following is more appropriate for a moderator? One which
Does not absorb neutrons
Absorbs neutrons
Accelerates neutrons
Eats up neutrons
In nuclear fission
The original elements change into completely different elements
The electrons of the element change
The molecules rearrange themselves to form other molecules
None of the above