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
Correct Answer :
D. Constant
Related Questions
Ferrite material is
The most fissionable material
The basic fuel for nuclear paints
Basic raw material for nuclear plants
The material which absorbs neutrons and undergoes spontaneous changes leading to the formation of fissionable material
Which of the following is the heaviest?
Neutron
Proton
Atom
Electron
A power plant giving least running cost of production of electrical power is
Steam power plant
Gas turbine power plant
Hydro electric power plant
Nuclear power plant
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 nuclear radiators produced in a reactor which must be shielded are
Electrons
α, β and γ rays
Neutron and gamma rays
None of these
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
The process by which a heavy nucleus is spitted into two light nuclei is known as
Splitting
Fission
Fusion
Disintegration
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
Superheated steam is generated in following reactor
Boiling water
Gas cooled
Pressurised water
All of the above
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
Plutonium (Pu239) is produced
Artificially
When U238 is irradiated by neutrons
By fission of Th232
As basic raw material
U235 will undergo fission by
High energy (fast) neutrons alone
Low energy (slow) neutrons alone
Either fast or slow neutrons
Medium energy neutrons
In triggering fission, which types of neutrons are more effective?
Fast
Slow
In bulk
Static
The energy required to be applied to a radioactive nucleus for the emission of a neutron is
1 MeV
2.4 MeV
4.3 MeV
7.8 MeV
The secondary fuel used in nuclear power plants is
U₂₃₃ and Pu₂₃₉
U₂₃₅ and Th₂₃₂
U₂₃₅ and Pu₂₃₈
U₂₃₃ and Pu₂₃₈
The presence of reflector in nuclear power plants results in
Increased production of neutrons
Complete absorption of neutrons
Controlled production of neutrons
Decreased leakage of neutrons
The fast breeder reactor uses the following moderator
Demineralised water
Carbon dioxide
Heavy water
No moderator is used
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
A fast breeder reactor
Uses graphite rods as moderator
Has powerful moderator
Has no moderator
Uses ferrite material as moderator
Reflector in nuclear plants is used to
Return the neutrons back into the core
Shield the radioactivity completely
Check pollution
Conserve energy
A reactor capable of converting a ferrite material into fissile isotopes is called
Regenerative reactor
Fast breeder reactor
Breeder reactor
Boiling water reactor
Enriched uranium may contain fissionable contents of the order of
1-99 %
1-25 %
1-50 %
1-75 %
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
Fast breeder reactor uses
Boiler
Direct cycle of coolant system
Double circuit system of coolant cycle
Multi passes system
A fast breeder reactor uses
90% U₂₃₅
U₂₃₈
U₂₃₅
Pu₂₃₉
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
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
Artificial radioactive isotopes find application in
Power generation
Nucleonic devices
Nuclear fission
Medical field
Pick up the wrong statement
In a heterogeneous or solid fuel reactor, the fuel is mixed in a regular pattern within moderator.
Slow or thermal neutrons have energy of the order or 0.025 eV
Fast neutrons have energies above 1000 eV
Fast reactor uses moderator
Which of the following type of pump is used in liquid metal cooled reactor for circulation of liquid metal
Centrifugal
Axial
Reciprocation
Electromagnetic