2. COURSE CONTENT
• Brief outlines of essential requirement of metals for nuclear energy programmes - Structural, fissile, moderator
and control.
• Rare metals – Minerals and their occurrence in India.
• Extraction of uranium, thorium, zirconium, beryllium and plutonium and their processing.
• Indian reactors and atomic energy programmes.
3. MARKS DISTRIBUTION
• Total Marks: 100
• Mid Term Exam: 30 Marks
• End Term: 50 Marks
• Assignment and Attendance: 20 Marks
4. INTRODUCTION
• World demand will almost double by the year 2040 (based on
2010 energy usage), which must be met by utilizing the
energy sources other than the fossil fuels such as coal and oil
• Fossil fuel power generation contributes to significant
greenhouse gas emissions into the atmosphere and influences
the climate change trend
• Many countries worldwide have recognized the importance
of clean (i.e. emission-free) nuclear energy
• Nuclear energy production worldwide by different countries
• United state: ~ 19% (2005 estimate) of its total energy
• France: ~ 79%
• Brazil and India: ~ 2.5% and ~ 2.8%
• Japan: ~ 30%
• South Korea: ~ 35%
• Switzerland: ~ 48%
Source: Ember's Yearly Electricity Data; Ember's European Electricity Review; Energy Institute
Statistical Review of World Energy in 2022
Nuclear Power Generation -2022
5. INTRODUCTION
• Nuclear reactors have been built for the
primary purpose of electricity production
• As the scope of the nuclear energy is
expanded, the role of materials is at the front
and center
6. TYPES OF NUCLEAR ENERGY
1. Nuclear Fission Energy
• Heat produced by the splitting of heavy radioactive atoms (nuclear fission) during the chain reaction is used
to generate steam (or other process fluid) that helps rotate the steam turbine generator, thus produced
electricity
• Most common mode of producing the bulk of the nuclear energy
Source: Uranium Nuclear Fission (hl-users.com) Source: scientificgamer.com
7. TYPES OF NUCLEAR ENERGY
2. Nuclear Fusion Energy
• A huge amount of energy (much higher than
fission) can be produced using the nuclear fusion
reaction (deuterium – tritium reaction)
• There is currently no commercial fusion reactors
• A prototype fusion reactors known as ITER
(International Thermonuclear Experimental
Reactor) is being built in France.
Source: scienceabc.com
8. FUSION IS A BETTER OPTION THAN
FISSION TO GENERATE POWER
• Nuclear fusion requires less fuel than fission
• Fusion is carried out by using deuterium (an isotope of hydrogen) as fuel, which is quite abundant in nature
• Fuel necessary for fission (uranium, plutonium or thorium) is very hard to get – and insanely expansive
• Nuclear fusion does not produce any radioactive waste (it produce only helium as a byproduct)
9. CHALLENGES AGAINST USING
NUCLEAR FUSION
1. Incredibly high energy requirement
• For fusion to occur, atleast 100,000,000 degree Celsius
(slightly more than 6 times the temperature of the Sun’s
core)
Source: scienceabc.com
• Experimental fusion reactors do exist – and work! – but
they consume way more power than they produce
10. CHALLENGES AGAINST USING
NUCLEAR FUSION
2. Material requirements
• Quite difficult to find materials that can withstand the reaction
• Need a special material that can withstand to such high temperatures
• Need lots of liquid helium to keep the entire setup cooled
3. Metallurgical problems
• Fusion reactions produce high-energy neutrons that hit the reactor walls
• This sort of radiation causes most alloying elements typically used in steel to become radioactive
• As of now, we don’t know what materials required to build fusion reactors so that its walls withstand
the extreme conditions
4. Budget and social stigma
• Money problem (anything related to nuclear power is usually considered a tough idea to sell to the
masses)
• There’s a social stigma around nuclear power that makes many believe that ‘nuclear energy is bad’
Source: scienceabc.com
11. TYPES OF NUCLEAR ENERGY
3. Radioisotopic Energy
• Either radioactive isotopes (e.g. 238Pu, 210Po) or
radioactive fission products (eg. 85Kr, 90Sr) can
produce decay heat that can be utilized to produce
electric power
• These types of power sources are mainly used in
remote space applications
Source: rps.nasa.gov/
12. NEUTRON CLASSIFICATION
• Chadwick discovered neutron in 1932
• Neutron is subatomic particle present in almost all nuclides with
a mass of 1.67 x 10-27 kg
• No electrical charge
Types of neutron
Cold Neutrons
(<0.003 eV)
Slow (thermal)
neutrons
(0.003-0.4 eV)
Slow
(epithermal)
neutrons
(0.4-100 eV)
Intermediate
neutrons
(100 eV-200
keV)
Fast neutrons
(200 keV-10
MeV)
High-energy
neutrons
(> 10 MeV)
15. NEUTRON SOURCES
• Sources of neutrons
5. Spallation neutron source
• The Spallation Neutron Source (SNS) is an accelerator-based neutron source facility in the U.S. that
provides the most intense pulsed neutron beams in the world for scientific research and industrial
development.
6. Photoneutron source
𝑈 + ℎ𝜈 → 𝑈 + 𝑛
16. INTERACTIONS OF NEUTRONS WITH
MATTER
• Elastic Scattering
• A neutron-nucleus event in which the kinetic energy and momentum are conserved
• Inelastic Scattering
• A neutron-nucleus interaction event when the kinetic energy is not conserved, while momentum is
conserved
• Transmutation
• When a nucleus captures neutrons,
• one result could be the start of a sequence of events that could lead to the formation of new nucleus
• Another result could be production of isotopes of original nucleus
• Fission
• A special case of transmutation reaction
18. GENERATION – I REACTORS
• Magnox Reactor
• Generation – I gas-cooled reactor
• Used for the purpose of plutonium production
(for nuclear weapons) as well as electricity
generation
• Magnox named from the name of Mg-based
alloy with small amount of Al and other
elements, magnesium nonoxidizing
• Ex: Mg-0.8Al-0.005Be
• Used natural uranium as fuel clad in thin
cylindrical tubes of Mg-alloy
• Carbon dioxide as coolant (heat transfer
medium)
Source: https://en.wikipedia.org/wiki/Magnox
𝑈 + 𝑛 → 𝑈 → 𝑁𝑝 + β → 𝑃𝑢 + β
19. GENERATION – I REACTORS
• Fuel: Natural Uranium Cladding tubes: magnesium based alloy Moderator: Graphite
• Coolant: Carbon-dioxide Pressure:300 psi Outlet temperature: 360 ℃
• Control Rods: Boron-steel rods Efficiency: 31%
• Issues with Magnox Reactor
• Limited power plant efficiency and power capacity
• Another problem was that the spent fuel from these reactors could not be safely stored under water because
of its chemical reactivity in the presence of water. Thus, the spent fuels needed to be reprocessed
immediately after taking out of the reactor and expensive handling of equipment was required.
20. GENERATION – II REACTORS
1. Light Water Reactors (LWRs)
• Light water as the coolant and the moderator
• Utilize thermalized neutrons to cause nuclear fission reaction of 235U atoms
• Thermal efficiency of the reactor: ~ 30%
• LWRs have routinely designed with 1000 MW capacity
Type of Light Water Reactors
Pressurized Water Reactor Boiling Water Reactor
21. GENERATION – II REACTORS
• Pressurized Water Reactor
• Most of the world’s nuclear power plants are almost
entirely made up of pressurized water reactors
• Pressure inside primary loop: 15 – 16 MPa
• Used enriched UO2 as fuel clad in Zircaloy-4 alloy
(new alloy is Zirlo or M5) tubes
• Cladding tube: outer diameter: ~ 10 mm
thickness: 0.7 mm
• Cladding fuel rods (around 200) are bundles
• Control Rod: made of Ag-In-Cd alloy or B4C
compound
• Steam generator: a heat exchanger contains thousands
of tubes nickel-bearing alloy (eg. Incoloy 800) or
nickel-based superalloy (eg. , Inconol 600)
Source: U.S.NRC (United States
Nuclear Regulatory Commission)
23. GENERATION – II REACTORS
Advantages
• Reactor easier to operate
• It contains "less fissile material”
• PWR turbine cycle loop is separate from the primary
loop, so the water in the secondary loop is not
contaminated by radioactive materials
Disadvantages
• Coolant water must be highly pressurized to remain
liquid at high temperatures
• High pressure components such as reactor coolant
pumps, pressurizer, steam generators, etc. are also
needed. This also increases the capital cost and
complexity of a PWR power plant.
• Most reactors need to be refueled after about 18
months, and cannot be refueled while the reactor is
running. Since the refueling process takes a few
weeks, the reactors must go offline for this time.
Pressurized Water Reactor
24. GENERATION – II REACTORS
Boiling Water Reactor
• The BWR is more or less similar to the PWR one
Fuel: enriched UO2
Cladding Tubes:
• Zicaloy-2 alloy tubes (~ 12.5 mm in outer diameter)
Control rods: B4C dispersed in 304-type stainless steel
matrix or hafnium or combination of both
Pressure:
• BWR operates at a pressure of about 7MPa
Steam temperature: 290 – 330 °C
Efficiency: 33-34%
Source: U.S.NRC (United States Nuclear
Regulatory Commission)
Operational BWR power plants in India: Tarapur Atomic Power Station – two unit with capacity 160 MWe (each)
25. BOILING WATER REACTOR
Fuel assembly
• Each fuel assembly contains ~ 90- 100 fuel
rods
• Upto 750 bundles
A nuclear fuel bundle for a BWR
26. ADVANTAGES AND DISADVANTAGES
OF BWR
Advantages
• Heat exchanger circuit is eliminated and
consequently there is gain in thermal efficiency
• Use of low pressure vessel for the reactor as compare
to PWR
• Cycle for BWR is more efficient than PWR for given
pressure
• Operates at a lower nuclear fuel temperature
Disadvantages
• Possibility of radioactive contamination in the
turbine mechanism
• More elaborate safety precautions needed which are
costly
• Maintenance is more difficult because of internal
contamination
• Lower power density – need larger core and Pressure
vessel then PWR
27. GENERATION – II REACTORS
2. Pressurized Heavy Water Reactor (or CANDU Reactor)
• They use heavy water (deuterium oxide) as the
moderator and natural uranium as the fuel
• Reactors are located mainly in Canada, India, China, and
few other countries.
• Used natural uranium (0.7% 235U) oxide as fuel clad in
zirconium alloy (Zr-2.5Nb alloy) tubes (also called
pressure tubes)
• Cladding tubes can be replaced while the system is
running
• Pressure tubes along with moderator and cooling tubes
are arranged in a horizontal fashion
28. ADVANTAGES AND DISADVANTAGES
OF CANDU
Advantages
• Enriched fuel is not required
• Heavy water is used as moderator which has low fuel
consumption
• Less time is needed to construct the reactor
Disadvantages
• Cost of heavy water is very high
• There are leakage problems
• It require high standards of design, manufacture,
maintenance
29. EXTRACTION OF PLUTONIUM FROM
SPENT FUEL
Pu-nitrate
solution Oxalic
acid
Pu(IV)
oxalate
ppt.
Heating
PuO2
Heating
with
HF
PuF4
PuF4 is then reduced by excess (25%) Ca in the presence of I (0.1 – 0.5 mol I2/mol of PuF4) at
600 °C in inert atmosphere
30. PROPERTIES OF PLUTONIUM
• Melting Point: 639 °C which is slightly below the melting point of aluminum (660 °C)
• Boiling point: 3235 °C
• Specific gravity: 19.5 which is near that of uranium
• Corrosion behavior: fresh surfaces have a silver-white lustre but they tarnish rapidly on exposure to air
• Hardness: 270 DPH (diamond pyramid hardness)
• Mechanical strength:
• Ultimate strength: 43.59 kg/mm2
• Yield strength: 26.01 kg/mm2
• Modulus of elasticity: 9.7 X 103 kg/mm2
