Nuclear power plants presentation

1. UNIT 3
NUCLEAR POWER PLANTS

2. Syllabus
Basics of Nuclear Engineering, Layout and
subsystems of Nuclear Power Plants, Working of
Nuclear Reactors : Boiling Water Reactor
(BWR), Pressurized Water Reactor (PWR),
CANada Deuterium- Uranium reactor (CANDU),
Breeder, Gas Cooled and Liquid Metal Cooled
Reactors. Safety measures for Nuclear Power
plants.

3. Nuclear Energy
Nuclear energy originates from the splitting of uranium atoms
in a process called fission. At the power plant, the fission
process is used to generate heat for producing steam, which is
used by a turbine to generate electricity

4. NUCLEAR POWER PLANT - LAYOUT

5. Nuclear Power plant

6. Components of Nuclear Power Plant
Nuclear Fuel :
Normally used nuclear fuel is uranium (U235)
Fuel Rods:
The fuel rods hold nuclear fuel in a nuclear power plant.
Neutron Source: A source of neutron is required to initiate the fission for
the first time. A mixture of beryllium with plutonium is commonly used
as a source of neutron.
Reactor:
•Nuclear fission takes place in the reactor only.
•Nuclear fission produces large quantity of heat.
•The heat generated in the reactor is carried by coolant circulated through
the reactor.

7. Nuclear Fission
Fast Neutrons
Moderator
U23
5
Moderator
Fission Fragment Fission Fragment
U23
5
Fission Fragment
Fission Fragment
Slow Neutrons
Slow Neutrons
Ba Kr

8. Nuclear Fission
• It is a process of splitting up of nucleus of fissionable material like uranium
into two or more fragments with release of enormous amount of energy.
•The nucleus of U235 is bombarded with high energy neutrons
U235+ n1
0
Ba 141+Kr92+2.5 n1+200 MeV energy.
0
• The neutrons produced are very fast and can be made to fission other
nuclei of U235, thus setting up a chain reaction.
• Out of 2.5 neutrons released one neutron is used to sustain the chain
reaction.
1 eV = 1.6X10-19 joule.
1 MeV = 106 eV

9. Working Principle of Nuclear Power Plant
• The heat generated in the reactor due to the fission of the
fuel is taken up by the coolant.
• The hot coolant then leaves the reactor and flows through
the steam generator.
• In the steam generator the hot coolant transfers its heat to
the feed water which gets converted into steam.
• The steam produced is passed through the turbine, which is
coupled with generator.
• Hence the power is produced during the running of turbine.
•The exhaust steam from the turbine is condensed in the
condenser.
•The condensate then flows to the steam generator through the
feed pump.

10. Advantages of Nuclear Power Plant
• Requires less space compared to steam power
plant.
• Fuel required is negligible compared to coal
requirement.
• Fuel transport cost is less.
• Reliable in operation.
• Cost of erection is less.
• Water required is very less.

11. Disadvantages of Nuclear Power Plant
• Initial Cost is higher.
• Not suitable for varying load condition.
• Radioactive wastes are hazardous. Hence these
are to be handled with much care.
• Maintenance cost is higher.
• Trained workers are required to operate the
plant.

12. Nuclear Power Plants in India
• IGCAR, Kalpakkam in Chennai.
• Rana Pratap Sagar in Rajasthan
• Narora in Uttar Pradesh
• Kakarpur near Surat at Gujarat
• Kaiga Power Plant at Karnataka.

17. TYPES OF REACTORS

18. NUCLEAR REACTOR

19. CONTROL OF NUCLEAR REACTOR
1. Graphite core, moderates neutron flux from fuel
rods
2. Boron control rods to reduce neutron flux for
shutdown
3. Thermal transfer control – closed circuit water/
steam loop. Multiple water pumps nitrogen/ helium
gas within containment – low thermal conductivity
and oxygen exclusion – pressure gas mixture are
controlled. Emergency core cooling water system
(ECCS)

20. MULTIPLICATION FACTOR .
• Multiplication is used to determine whether
the chain reaction will continue at a steady
rate, increase or decrease. It is given by the
relation,
• K = P/ ( A+E)
• K = Effective multiplication factor
• P = rate of production of neutrons
• A = Combined rate of absorption of neutrons
• E = Rate of leakage reactance

21. Pressurized water reactor (PWR)
• Moderator and coolant are light water (H2O).
• Cooling water circulates in two loops .Water is kept
under pressure. So water heats but does not boil.
• Pressurizer is used to maintain constant pressure.
• If pressure drops, water in the pressurizer is heated
up by electric heaters. If pressure increases, cooling
water is injected to pressurizer.

22. Pressurized water reactor

23. The pressurized water reactor

24. • Primary circuit water transfers its heat to
secondary circuit water, cools down and
returns to reactor vessel. Both water circuits
are separate and can’t mix.
• Primary pressure-12 to 16 bars.
• Outlet temperature of coolant- 300C.
• Widely used type

25. Boiling water reactor
• H2O is moderator and coolant.
• Only a part of water boils away in
reactor, a mixture of water and steam
leaves reactor core.
• Pressure is only 6 to 7 bars.
• Fuel UO2
• Simple, low cost construction.

26. Boiling water heater

27. Boiling water heater

28. Waste disposal and safety Hydel
power plant
• Disposal of radioactive waste from nuclear
power plants and weapons facilities by recycling
it into household products.
• In 1996, 15,000 tons of metal were received by
the Association of Radioactive Metal Recyclers .
Much was recycled into products without
consumer knowledge.
• Depleted Uranium munitions for military.

29. Current World Demand for Electricity

30. Future Demand
Projected changes in world electricity generation by fuel, 1995 to 2020

31. Emission-Free Sources of Electricity
73.1%
24.2%
1.3% 1.0% 0.1%

32. Basics of a Power Plant
• The basic premises for the majority of
power plants is to:
– 1) Create heat
– 2) Boil Water
– 3) Use steam to turn a turbine
– 4) Use turbine to turn generator
– 5) Produce Electricity
• Some other power producing technologies
work differently (e.g., solar, wind,
hydroelectric, …)

33. Nuclear Power Plants use the
Rankine Cycle

34. Create Heat
• Heat may be created
by:
– Burning coal
– Burning oil
– Other combustion
– Nuclear fission
1) oil, coal or gas
2) heat
3) steam
4) turbine
5) generator
6) electricity
7) cold water
8) waste heat water
9) condenser

35. Boil Water
• The next process it to
create steam.
• The steam is necessary
to turn the turbine.

36. Turbine
• Steam turns the turbine.

37. Generator
• As the generator is
turned, it creates
electricity.

38. Heat From Fission

39. Fission Chain Reaction

40. Nuclear History
• 1939. Nuclear fission discovered.
• 1942. The world´s first nuclear chain reaction takes place in Chicago as part
of the wartime Manhattan Project.
• 1945. The first nuclear weapons test at Alamagordo, New Mexico.
• 1951. Electricity was first generated from a nuclear reactor, from EBR-I
(Experimental Breeder Reactor-I) at the National Reactor Testing Station in
Idaho, USA. EBR-I produced about 100 kilowatts of electricity (kW(e)),
enough to power the equipment in the small reactor building.
• 1970s. Nuclear power grows rapidly. From 1970 to 1975 growth averaged
30% per year, the same as wind power recently (1998-2001).
• 1987. Nuclear power now generates slightly more than 16% of all electricity
in the world.
• 1980s. Nuclear expansion slows because of environmentalist opposition,
high interest rates, energy conservation prompted by the 1973 and 1979 oil
shocks, and the accidents at Three Mile Island (1979, USA) and Chernobyl
(1986, Ukraine, USSR).
• 2004. Nuclear power´s share of global electricity generation holds steady
around 16% in the 17 years since 1987.

41. Current Commercial Nuclear Reactor
Designs
• Pressurized Water Reactor (PWR)
• Boiling Water Reactor (BWR)
• Gas Cooled Fast Reactor
• Pressurized Heavy Water Reactor
(CANDU)
• Light Water Graphite Reactor (RBMK)
• Fast Neutron Reactor (FBR)

42. The Current Nuclear Industry

43. Nuclear Reactors Around the World

44. PWR

45. BWR

46. CANDU-PHWR

47. PTGR

48. Hydrogen Production
• Hydrogen is ready to play the lead in the next
generation of energy production methods.
• Nuclear heat sources (i.e., a nuclear reactor)
have been proposed to aid in the separation of H
from H20.
• Hydrogen is thermochemically generated from
water decomposed by nuclear heat at high
temperature.
• The IS process is named after the initials of each
element used (iodine and sulfur).

49. Hydrogen Production (cont.)

50. Closed Fuel Cycle
• A closed fuel cycle is
one that allows for
reprocessing.
• Benefits include:
– Reduction of waste
stream
– More efficient use of
fuel.
• Negative attributes
include:
– Increased potential for
proliferation
– Additional
infrastructure

51. Simplification
• Efforts are made to simplify the design of
Gen IV reactors. This leads to:
– Reduced capitol costs
– Reduced construction times
– Increased safety (less things can fail)

52. Increased Safety
• Increased safety is always a priority.
• Some examples of increased safety:
– Natural circulation in systems
– Reduction of piping
– Incorporation of pumps within reactor vessel
– Lower pressures in reactor vessel (liquid
metal cooled reactors)

53. Gas Cooled Fast Reactor
(GFR)
• The Gas-Cooled Fast
Reactor (GFR) system
features:
– fast-neutron-spectrum
– helium-cooled reactor
(Brayton Cycle)
– closed fuel cycle
(includes reprocessing)

54. Gas Cooled Fast Reactor (GFR)
• Like thermal-spectrum, helium-cooled reactors, the high
outlet temperature of the helium coolant makes it
possible to:
– deliver electricity
– produce hydrogen
– process heat with high efficiency.
• The reference reactor is a 288-MWe helium-cooled
system operating with an outlet temperature of 850
degrees Celsius using a direct Brayton cycle gas turbine
for high thermal efficiency.

55. Very High Temperature Reactor
(VHTR)
• The
Very-High-Temperature
Reactor (VHTR) is
– graphite-moderated
(thermal spectrum)
– helium-cooled reactor
– once-through uranium
fuel cycle (no
reprocessing)
– core outlet
temperatures of 1,000
◦C

56. Supercritical Water Cooled Reactor
(SCWR)
• The
Supercritical-Water-Coo
led Reactor (SCWR)
system:
– high-temperature
– high-pressure
water-cooled reactor
above
that operates
the thermodynamic
critical point of water
(374 degrees Celsius,
22.1 MPa, or 705
Fahrenheit,
degrees
3208 psia).

57. What is a supercritical fluid?
• A supercritical fluid is a
material which can be
either liquid or gas,
used in a state above
the critical temperature
and critical pressure
where gases and liquids
can coexist. It shows
unique properties that
are different from those
of either gases or
liquids under standard
conditions.

58. WASTE DISPOSAL
• LIQUID WASTE
• Dilution
• Concentration to small volumes and
storage
• GASEOUS WASTE
• SOLID WASTE

63. Governing of Turbines

64. Governing of Turbines
• Governing system - regulates the turbine
speed, power and participates in the grid
frequency regulation.
• Main operator interface for starting &
loading.
• Plays a key role on Steady state and
dynamic performance

65. Governing of Turbines
• Need for governing system:
– Mismatch between load and generation results in the speed (or
frequency) variation.
– When the load varies, the generation also has to vary to match it
to keep the speed constant.
– Done by the governing system.
– Speed which is an indicator of the generation – load mismatch is
used to increase or decrease the generation.

66. Pelton Wheel

67. Governing of pelton wheel

69. Governing of Francis turbine

70. Kaplan turbine

71. Governing of Kaplan turbine

72. THANK YOU