ME708 NUCLEAR ENGINEERING
UNIT – I
NUCLEAR PHYSICS
1. What are the advantages of nuclear power?
No atmospheric pollution by combustion products.
Space requirements less as compared to other conventional power
plants are of equal size.
2. List down the disadvantages of nuclear power?
High initial cost and complexity of nuclear fuel cycle are beyond the
reach of poor developing countries.
Nuclear power plants are not well suited for varying load conditions.
3. What is atom?
The smallest particle of an element which takes part in chemical
reaction is known as an atom.
4. How does empirical approach differ from intuitive approach?
The design of an experiment with the results of the experiment is the
basis for the formation of the model or theory called the empirical
approach to model building.
5. What is called nucleus?
The atom consists of two distinct regions. The tiny central core is
called the nucleus with a radius of ~10^-15 m and extensive surrounding
space is called as outer sphere with a radius of 10^-10 m.
6. What is the atomic number and mass number?
The number of protons in the nuclear is called atomic number. It is
denoted by Z. The total number of nucleons in the nuclear is called mass
number. It is denoted by the letter A.
7. What is an isotope?
Some elements exist in different forms. Mass number of these
different forms is different, but the atomic number is the same. They are
known as isotopes of the element.
8. Write down the Einstein energy equation.
Energy, E = mc².Where m = mass and c = light speed = 3*10^8 m/s.
9. List down some isotopes used in fusion reaction?
Protium, Deuterium, Tritium, Helium-3, Helium-4.
10. List down the factors considered for stable and unstable nucleus?
Even – odd nature of the number of protons and neutrons.
The ratio of neutrons to protons.
11. What is nuclear binding energy?
The energy released at the moment of combination of two nucleons
to form nucleus of an atom is called binding energy.
12. Define the term one electron volt.
One electron volt is the amount of energy acquired by any particle
with one electronic charge when it falls through a potential of one volt.
13. How much inone eV in joule?
One eV = 1.602*10^-9 N-m or joule.
14. What is radio activity?
Radio activity is the phenomenon of spontaneous emission powerful
radiation exhibited by heavy elements.
15. List down the types of radioactive decay.
Α-emission, β-emission, γ-emission.
16. Define the term half-life.
The half-life of any given elements is the time which is required for
one half of the sample to decay.
17. Mention the types of nuclear interactions.
1. Elastic scattering 2.In Elastic scattering.
18. What are the reactions held by a neutron in the nucleus?
1. Radiative capture 2. Particle ejection scattering.
19. What are the various methods used for determining the cross section?
1. Transmission method 2. Activation method.
20. Mention the two types of scattering cross section.
Coherent scattering and incoherent scattering.
21. What is called positron?
β+ is a positron emitted from the nucleus. It is a positive electron and
animatter. It is also emitted when a nucleus has too many protons.
22. Define natural and artificial radioactivity.
Natural radioactivity is isotopes that have been here since the earth
formed. Example : Uranium.
Artificial radioactivity is productivity by cosmic rays from the sun.
23. How can decay constant be defined?
The probability per unit time for a given nucleus to decay is called
decay constant λ.
24. Mention the types of cross section?
1. The cross section σ for a particular process which applies to a single
nucleus, it is called microscopic cross section.
2. If the cross section for the same process is considered for whole
nucleus, it is called macroscopic cross section.
25. What is called plum pudding?
Thompson proposed a model for the atom consisting of a positive
electrical field with electrons embedded into the field like plums embedded in
plum pudding. It is called plum pudding model of the atom.
UINT-2
Nuclear Reaction and Reaction Materials
1.Name primary and secondary nuclear fuels used in nuclear power
(I) U235is primary fuel
(II)U233 and PU239 are secondary fuels
2.What are called fissile isotopes?
These fuels undergo fission process. When unstable heavy nuclear is
bombarded with neutrons it spilts into two fragement of approximately equal
mass. Large amount of heat is released during this fission process
3.How can we define fertile fuels?
U235 is produced by nuclear reaction of thorium element.PU239 is produced by
neutron irradiation of U238 . These PU239 and U233 can be fissioned by neutrons.
U238 and Th232 are known as fertile fuels
4.What is nuclear fission?
Nuclear fission is the process of splitting of nucleus into two almost equal
fragments accompanied by the release of heat.
5.What are the conditions satisfied to sustain nuclear fission process?
 The fission process must liberate the energy
 It must be possible to control the rate of energy liberation
6.How is nuclear energy calculated?
Nuclear energy is measured by albert Einstein formula,
E= mc2
E=energy
M=mass
C=velocity or the speed of light
7.What is called cosmium?
The hypothetical nuclide is called as cosmium.
8.Define the term photofission.
r photons from nuclear reaction are capable of fissioning a number of
heavy nuclides called photofission
9.What is nuclear fusion?
Nuclear fusion is the process of cobining of fusing two lighter nuclei into
a stable and heavier nuclide. In this process also large amount of energy is
released because mass of the product nucleus is less very when compared to
mass of the two nuclei which are fussed
10.Give the steps of proton-proton chain of fusion reaction?
 Two pairs of protons from to make two deuterium atoms
 Beryllium-6 decays into two helium-4 atoms.
11.Mention the types of hydrogen fusion.
 Magnetic confinement uses magnetic and electric fields to heat
squeeze the hydrogen plasma.
 Inertial confinement uses laser beams or ion beams to squeeze
and heat hydrogen plasma
12.Define chain reaction.
This chain reaction is the process in which the number of neutrons
keeps on multiplying rapidly during the fission till whole of the fissionable
material is disintegrated.
13.Define multiplication factor or reproduction factor.
This condition can be conveniently expressed in the form of
multiplication factor or reproduction factor of the system which may be
defined as
K=Number neutrons in any particular generation
Number neutrons in the preceding generation
14.What are the requirements to sustain the nuclear chain reaction?
 The fission process must liberate the energy
 It must be possible to control the rate of energy liberation
15.Iist down the requirements of a moderator.
 It should have as low atomic mass number as possible and
 Its neutron absorbing ability should be as low as possible
16.What is neutron generation?
Neutron generation is the time that elapses between the birth of a
neutron and the birth of neutrons from the subsequent fission which is caused
by the given neutron.
17.Defne the term critical mass?
The point at which the chain reaction can become self-sustaining is known
as critical mass.
18.Name few common enrichment techniques employed in nuclear fuel cycle.
 Gaseous diffusion
 Gas centrifuge
 Thermal diffusion
19.sate the role of fuel fabrication in nuclear fuel cycle.
Nuclear fuel fabrication converts the enriched UF6 into fuel for nuclear
power reactors.
20.Name the methods used to concentrate and purify uranium.
 Non exchange, and
 Solvent extraction
UNIT-3
REPROCESSING
1.Define reprocessing as applied to nuclear fuel?
Nuclear reprocessing separates any usable elements from fission products
and other materials in used nuclear reactor fuels.
2. State the major composition of nuclear spent fuel?
95.6% uranium(less than 1% of which is 235U); 2.9% stable fission
products and 0.9% plutonium (about two thirds fissile 239Pu & 241Pu).
3. Define Mixed oxide or MOX fuel?
Mixed oxide or MOX fuel is a blend of plutonium and natural or depleted
uranium which behaves similarly to the enriched uranium feed for which most
nuclear reactors were designed. MOX fuel is an alternative to Low enriched
uranium fuel used in the light water reactors which predominate nuclear
power generation.
4.Define Transmutation in nuclear reprocessing?
The process of conversion of long lived fission products to shot-lived isotopes
by either neutron or photon irradiation is called transmutation.
5.Define Nuclear fuel cycle/
The nuclear fuel cycle, also called nuclear fuel chain, is the progression of
nuclear fuel through a series of differing stages.
6.Define closed nuclear fuel cycle?;
Reprocessing separates the uranium and plutonium from the wastes so
that they can be recycled for re-use in a nuclear reactor as a mixed oxide(MOX)
fuel. This is the closed fuel cycle.
7.Define open fuel cycle?
If spent fuel is not reprocessed, the fuel cycle is referred to as an open
fuel cycle or a once-through fuel cycle.
8.State the stages in nuclear fuel cycle?
The nuclear fuel cycle consists of three important steps:
Steps in the front end – preparation of the fuel.
Steps in the service period – fuel is used during reactor operation.
9.Define extraction?
Liquid-Liquid extraction is a mass transfer operation in which a liquid
solution (the feed) is contacted with an immiscible or nearly immiscible liquid
(solvent) that exhibits preferential affinity or selectivity towards one or more
of the components in the feed.
10.Define the term selectivity in extraction?
The selectivity is expressed by the separation factor the ratio of the
distribution coefficients of the desired and impurity species when equilibrium
is attained between two phases.
11.Define the term distribution coefficient?
The distribution coefficient ratio D is defined as
D=(Concentration of component in oranic phase)/(Concentration of
component in aqueous phase)
12.Define separation factor?
At equilibrium the separation factor α is given by
Α=D(product)/D(Impurity)
13.Name the common types of extractor used in nuclear industries?
(I) Mixer-Settlers
(II) Centrifugal Devices
(III) Column contactors (Static and agitated columns)
UNIT-4
Nuclear Reactors
1.What do you understand by moderation?
The process of slow down the neutrons from high velocity without
capturing them is know as modulation.
2.Explain the unction of the moderator?
moderator is a material which is used to slow down the neutrons from high
velocities without capturing them. The fast moving neutrons are far less
effective in causing the fission and try to escape from the reactor.
3.What are the desired properties required for good moderator?




High thermal conductivity.
High slowing down power.
Low parasite capture
Lighter
4. What are the function of control rods?
The function of control rod is:
*To control the rate of fission
*To start the nuclear chain reaction, when reactor is started from cold.
*To shut down the reactor under emergency condition.
5.Classify the different types of nuclear reactor?
(I) According to the neutrons energy
 Fast reactors-Fast fission is caused by high-energy neutrons.
 Intermediate or epithermal
 Low energy or Thermal reactors-Fission is due to slow moving
neutrons
(II) According to the fuel used
1. Natural fuel reactor – Natural uranium is used as fuel.
2. Enriched uranium reactor – uranium used in this reactor
contains 5 to 10% of U 235.
(III) According to the type of moderators used
1. Graphite moderator reactor
2. Berylium moderator reactor
3. Water moderator reactor
6. Define the term “Breeding”
In fast breeder reactor, the process of producing energy to self-sustain
nuclear fission chain reaction without using moderator is known as
breeding.Enriched Uranium or Plutonium is used as fuels which are surrounded
by a thick blanket of fertile Uranium.
7. What factors control the selection of a particular type of a reactor?
1. Neutrons energy
2. Type of fuel
3. Type of coolant
4. Type of moderators
5. Construction of core.
8. What is generation III in nuclear reactors?
Generation III involves optimizing the current reactors, in terms of
economics and safety. These reactors are likely to be deployed before 2010.
9. What is generation IV? State its application.
Generation IV comprises nuclear systems likely to reach technical
maturity by 2030. Their design will take cognizance of the progress made in
economics and safety. In addition, the aim is for these reactors to support
sustainable energy development worldwide, and to open up the range of
nuclear systems’” application to hydrogen generation for transport (in addition
to electricity production).
10. State the goals of generation IV?
(I) Sustainable
(II) Economically viable
(III) Safe and reliable
11. What are the different types of fast breeders?
(I) GFR : Gas-cooled Fast Reactor system cooled with helium
(II) LFR: Lead Fast Reactor cooled with lead or lead-bismuth eutectic
(III) MSR: Molten salt Reactor fuelled with molten salts.
12.State the advantage of fast breeder reactors.
 No moderator is required
 High breeding is possible
 Better fuel utilization
13.Point out any four disadvantages of gas cooled reactors.
 Fuel loading is more elaborated and costly.
 The cost of heavy water(D2O) is high (Rs.500 per kg)
 Large amount of fuel loading is initially required since the critical
mass is high
14.Give the range of power and fuel cycle in sodium-cooled reactors.
 A 150-to500MW reactor with a metal alloy fuel,
supported by a fuel cycle based on pyro-metallurgical
processing, and
 A 500-to 1,5000Mw reactor with mixed oxide fuel
supported by a fuel cycle based upon advanced aqueous
processing.
15.State the advantages of sodium fast reactor.
 No moderator required
 Sodium doesn’t react with Uranium and thorium
 Fuel can be bonded to container with liquid metal
16.What are the components of supercritical water reactor nuclear power
plant?
 Reactor
 Pressuriser
 Heat exchanger
17.Write the different fuel cycle can be used in Molten salt reactor.
 Actinide burning fuel cycle
 Once-through fuel cycle
 Thorium-233 U breeder cycle
18.Mention the advanced designs in FBR.
 Evolutionary designs
 Innovative designs
19.What are the key elements considered to select generation IV systems?.
 Among the goals and criteria sustainability has been the most
discriminating. This is demonstrated by the majority of the systems
having fast neutron spectra and closed fuel cycles.
 The grouping of system in families is according to homogeneity in
performance and R&D needs.
20.List down the factors not considered for heat transfer analysis.
 Multiphase flow
 Condensation with non-condensable
 Lower Head Cooling
21.Mention the different types of shielding.
 Radiation shielding
 Neutron shielding
22.State the various types of fusion reactors used for power generation.
 Magnetic confinement fusion reactors ( tokamak fusion test reactor)
 Inertial confinement fusion reactors
Unit-5
Safety and disposal
1.what are the major reason for nuclear accidents that classified under lower
probability?
Cracks in coolant pipes and lossof flow are the major reasons for nuclear
accidents of lower probability.
2.State the major reasons for nuclear accidents that classified under moderate
frequency?
The major reasons for nuclear accidents of moderate frequency are
imbalance in heat rates, increase in thermal power and decrease in cooling
effectiveness.
3. State the major reasons for nuclear accidents that classified under severe
accidents?
The major reasons for nuclear accidentsof severe category are large break
of loss coolant, loss of power in reactor station and failure of reactor
protection system.
4.State the engineered nuclear plant safety measures adopted?
The major engineered safety features are
(I)
Emergency cooling system to supply water to the reactor core in the
event of a loss of coolant accident.
The containment vessel to provide a barrier to the escape to the
environment of radioactivity.
(II)
5. What are the criteria used for evaluation of nuclear plant safety?
The criteria used for the evaluation of nuclear plant safety are
(I)
(II)
(III)
No unreasonable risk
Adequate protection of public health and safety.
Risk as low as reasonably practicable.
6. State the major problem encountered in nuclear power generation?
The nuclear power generation poses mainly two problems such as
(I)
(II)
The management of radioactive waste, and
The danger passed in case of accident is very high and long
standing.
7.How nuclear wastes are classified?
The nuclear wastes are classified as:
(I)
(II)
On the basis of half life time
(a) Fission products
(b) Actinides
(c) The neutron activation products
On the basis of the intensity of radiation
(a) Low level waste
(b) Medium level waste
(c) High level waste.
8.What are the types of radiation which has the ability to penetrate objects or
Bodies?
Alpha,Beta,and Gamma radiation.
9.State the common units of radiation?
Red: The absorbed dose unit is called as red which is defined as the
amount of radiation that leads to deposition of 10-2j of energy per kg of the
absorbing material.
Rem: The effect of a given adsorbed dose of radiation is expressed in
terms of the dose equivalent for which the unit is rem.
10.State the beneficial uses of nuclear radiation?
(I) Nuclear radiation has a number of beneficial uses, including:
(II) Medicinal, such as radio therapy for cancers and X-rays
(III)
Dating purposes (no, this not where you nuke a toxic date).
11.State the long term effects of radiation?
Blood disorders, cataracts, keloids and malignant tumors.