The document discusses the basic structure and operation of nuclear power plants. It describes how nuclear fission produces heat that is used to generate electricity. Nuclear power plants use uranium fuel in a reactor core to produce heat and steam that drives turbines connected to generators, producing electricity. The document outlines the major components of nuclear power plants including the reactor, steam generators, turbines and various safety systems. It also discusses different types of reactors and the benefits of nuclear energy.
6. CONTENTSCONTENTS
• Picture of nuclear power plantPicture of nuclear power plant
• Needs of nuclear power plantNeeds of nuclear power plant
• Nuclear energy- A unique value propositionNuclear energy- A unique value proposition
• Basic structure of nuclear power plantBasic structure of nuclear power plant
• Layout of nuclear power plantLayout of nuclear power plant
• Dual fluid nuclear power plantDual fluid nuclear power plant
• Benefits of nuclear power plantBenefits of nuclear power plant
• Environmental benefitsEnvironmental benefits
• LimitationLimitation
• Going forwards from 2005Going forwards from 2005
• Site selectionSite selection
• Basic principal of nuclear energyBasic principal of nuclear energy
• The fission reactionThe fission reaction
• How a Nuclear Power Plant Works: FuelHow a Nuclear Power Plant Works: Fuel
• Types of RadiationTypes of Radiation
• Main part of nuclear reactor and reactor controlMain part of nuclear reactor and reactor control
• Multiple Layers to SafetyMultiple Layers to Safety
• Classification of nuclear reactorClassification of nuclear reactor
• Basic reactor systemBasic reactor system
• Pressurized water reactorPressurized water reactor
• Boiling water reactorBoiling water reactor
• Advanced Gas Cooled ReactorAdvanced Gas Cooled Reactor
• Heavy Water Reactor / canduHeavy Water Reactor / candu
• The History of Nuclear Energy DeploymentThe History of Nuclear Energy Deployment
9. Nuclear Energy:Nuclear Energy:
A Unique Value PropositionA Unique Value Proposition
Safe,
Reliable,
Competitive
Electricity
Forward
Price
Stability
Clean Air,
Carbon-Free
Value
10. BASIC STRUCTURE OF NUCLEARBASIC STRUCTURE OF NUCLEAR
POWER PLANTPOWER PLANT
11. LAYOUT OF NUCLEAR POWER PLANTLAYOUT OF NUCLEAR POWER PLANT
REACTOR
Containment
and biological
shield
TURBINE GENERATOR
FEEDPUMF
(SINGLE FLUID SYSEM)
13. Benefits of Nuclear PowerBenefits of Nuclear Power
Reduce demand of CoalReduce demand of Coal
Stable fuel costStable fuel cost
Improves the environmentImproves the environment
Less space is requiredLess space is required
Bigger capacity gives additional advantageBigger capacity gives additional advantage
Economic benefits – jobs & economyEconomic benefits – jobs & economy
Waste product is controlled, stored,Waste product is controlled, stored,
monitored, protected and regulatedmonitored, protected and regulated
Proven, reliable, low-cost supplier ofProven, reliable, low-cost supplier of
electricityelectricity
14. Environmental BenefitsEnvironmental Benefits
• Nuclear generators eliminate Greenhouse gasNuclear generators eliminate Greenhouse gas
generationgeneration
• Existence of a nuclear plant assists in sitingExistence of a nuclear plant assists in siting
industrial facilities (environmental cap &industrial facilities (environmental cap &
trade)trade)
• Eases burden of siting fossil fueled plantsEases burden of siting fossil fueled plants
• Assists in maintaining a balanced & diversifiedAssists in maintaining a balanced & diversified
generating portfoliogenerating portfolio
15. LIMITATIONLIMITATION
• Danger of RadioactivityDanger of Radioactivity
• Health of WorkerHealth of Worker
• Disposal of Radio Activity WasteDisposal of Radio Activity Waste
• High salaries of trained personHigh salaries of trained person
• Very High Initial Capital CostVery High Initial Capital Cost
16. Going Forward from 2005Going Forward from 2005
Nuclear power plants provide safe,
reliable, low-cost electricity
Stable cash flow
Hedge against volatility in
natural gas price and supply
Safeguard against escalating
environmental requirements
Environmental
Value
Forward
Price Stability
Low Cost
Safe and
Reliable
17. SITE SELECTIONSITE SELECTION
(Following point keep in mind)(Following point keep in mind)
SafetySafety
Availability of cooling water supplyAvailability of cooling water supply
Transmission and load centerTransmission and load center
Fuel type and AvailabilityFuel type and Availability
Radioactive waste disposalRadioactive waste disposal
AccessibilityAccessibility
Foundation conditionsFoundation conditions
18. BASIC PRINCIPLES OF NUCLEAR ENERGY
Nuclear Fission
The animation below shows a uranium-238 nucleus with a neutron
approaching from the top. As soon as the nucleus captures the
neutron, it splits into two lighter atom and throws off two or three
new neutrons (the number of ejected neutrons depends on how the
U-238 atom happens to split). The two new atoms then emit gamma
radiation as they settle into their new states.
19. The Fission Reaction
The mass of the fission products is less than the
initial nucleus and neutron
Some of the mass has been converted to
kinetic energy of the fission products
Energy released is 200 MeV - about 10 million
times the energy released by chemical combustion
of a fuel molecule
20. There are three things about this induced fissionThere are three things about this induced fission
process that make it especially interestingprocess that make it especially interesting
The process of capturing the neutron and splitting happens veryThe process of capturing the neutron and splitting happens very
quickly, on the order of picoseconds (1x10-12 seconds).quickly, on the order of picoseconds (1x10-12 seconds).
The probability of a U-235 atom capturing a neutron as it passes byThe probability of a U-235 atom capturing a neutron as it passes by
is fairly high. In a reactor working properly (known as theis fairly high. In a reactor working properly (known as the criticalcritical
statestate), one neutron ejected from each fission causes another fission), one neutron ejected from each fission causes another fission
to occur.to occur.
An incredible amount of energy is released, in the form of heat andAn incredible amount of energy is released, in the form of heat and
gamma radiation, when a single atom splits. The two atoms thatgamma radiation, when a single atom splits. The two atoms that
result from the fission later release beta radiation and gammaresult from the fission later release beta radiation and gamma
radiation of their own as well. The energy released by a single fissionradiation of their own as well. The energy released by a single fission
comes from the fact that the fission products and the neutrons,comes from the fact that the fission products and the neutrons,
together, weigh less than the original U-235 atom. The difference intogether, weigh less than the original U-235 atom. The difference in
weight is converted directly to energy at a rate governed by theweight is converted directly to energy at a rate governed by the
equationequation E = mc2E = mc2
21. How a Nuclear Power Plant Works:How a Nuclear Power Plant Works:
FuelFuel
Uranium-238 atoms are split apart in a process called
nuclear fission.
As more and more atoms split inside the reactor, a large
amount of heat is produced.
22. Types of RadiationTypes of Radiation
Alpha Particle - A positive charged particle emitted by certain
radioactive materials. Alpha particles can be stopped by a sheet
of paper.
Alpha Radiation - The least penetration type of radiation: emission
of positive charged particles by certain radioactive materials
Beta particle - A negatively charged particle emitted from an atom
during radioactive decay. A beta particle can be stopped by an inch
of wood or a thin sheet of aluminum.
Beta Radiation - Emitted from the nucleus during fission: emission
of negatively charged particles during radioactive decay.
23. MAIN PART OF NUCLEAR REACTORMAIN PART OF NUCLEAR REACTOR
AND REACTOR CONTROLAND REACTOR CONTROL
CORE
FULE RODS
Control Rods
MODERATOR
Coolant OUT
Coolant IN
STEAM
TO
STEAM
TURBINE
RADIATION SHIELDREFLECTOR
HEAT
EXCHANGER
OR STEAM
GENERATOR
24. Containment Vessel
1.5-inch thick steel
Shield Building Wall
3-foot thick reinforced concrete
Dry Well Wall
5-foot thick reinforced concrete
Bio Shield
4-foot thick leaded concrete with
1.5-inch thick steel lining inside and out
Reactor Vessel
4- to 8-inches thick steel
Reactor Fuel
Weir Wall
1.5-foot thick concrete
25. Multiple Layers to SafetyMultiple Layers to Safety
45 inch steel-reinforced concrete
1/4 inch steel liner
36 inch concrete shielding
8 inch steel reactor vessel
nuclear fuel assemblies
26. CLASSIFICATION OF NUCLEAR REACTORCLASSIFICATION OF NUCLEAR REACTOR
On The Basis Of Neutron EnergyOn The Basis Of Neutron Energy
IN THERMAL REACTOR / neutron energy ( 0.03 ev)IN THERMAL REACTOR / neutron energy ( 0.03 ev)
IN FAST REACTOR / neutron energy (1000 ev)IN FAST REACTOR / neutron energy (1000 ev)
IN INTERMEDIATE REACTOR / ( in b/w )IN INTERMEDIATE REACTOR / ( in b/w )
On The Basis Of FuelOn The Basis Of Fuel
One of the material can be useOne of the material can be use
U-233 , U-335 , U-339U-233 , U-335 , U-339
On The Basis Of Type Of Coolant UsedOn The Basis Of Type Of Coolant Used
GAS (CO2, H2)GAS (CO2, H2)
LIGHT WATERLIGHT WATER
HEAVY WATERHEAVY WATER
LIQUID METALHYDRO CARBONLIQUID METALHYDRO CARBON
HYDROCARBONHYDROCARBON
27. On The Basis Of Moderator UsedOn The Basis Of Moderator Used
Light WaterLight Water
Heavy waterHeavy water
GraphiteGraphite
OrganicsOrganics
On The Basis of Type of Fuel EnrichmentOn The Basis of Type of Fuel Enrichment
Natural FuelNatural Fuel
Enriched FuelEnriched Fuel
On The Basis of Geometry of Fuel ModeratorOn The Basis of Geometry of Fuel Moderator
ArrangementArrangement
Homogeneous( fuel is homogeneously dispersed in theHomogeneous( fuel is homogeneously dispersed in the
moderator)moderator)
Heterogeneous( fuel in the form of rod or plates in the matricesHeterogeneous( fuel in the form of rod or plates in the matrices
of moderator)of moderator)
28. On The Basis Of Their Applications, Function AndOn The Basis Of Their Applications, Function And
ConstructionConstruction
Research teaching and material testing reactorResearch teaching and material testing reactor
Plutonium production reactor which produce fissilePlutonium production reactor which produce fissile
material from fertile material or produce isotopesmaterial from fertile material or produce isotopes
Power reactorsPower reactors
• Stationary power plantStationary power plant
• Center station power reactorCenter station power reactor
• Package reactor for easy mobility, specially for defensePackage reactor for easy mobility, specially for defense
purposepurpose
Mobile reactor , Naval reactor , merchant ship reactorMobile reactor , Naval reactor , merchant ship reactor
Space reactor which are used in space craftSpace reactor which are used in space craft
Food irradiation reactorFood irradiation reactor
29. BASIC REACTOR SYSTEMBASIC REACTOR SYSTEM
Pressurized water reactorPressurized water reactor
Boiling water reactorBoiling water reactor
Sodium graphite reactorSodium graphite reactor
Fast breeder reactorFast breeder reactor
Homogeneous reactorHomogeneous reactor
Organic cooled and moderator reactorOrganic cooled and moderator reactor
Gas cooled reactorGas cooled reactor
High temperature gas cooled reactorHigh temperature gas cooled reactor
35. The History of Nuclear EnergyThe History of Nuclear Energy
DeploymentDeployment
36. Decade of Safety & EconomicDecade of Safety & Economic
ImprovementImprovement
¬
¬
¬
¬
¬
¬
¬
¬
k5
á J ~ â K € ´ é @Z uZ
µ
µ
µ
µ
µ
µ
µ
Relative Cost
Risk (CDF) Capacity Factor
Year
Based on UDI, DOE NUS Data plus info. from ERIN Eng EPRI
Relative Cost
Relative Risk
Capacity
Factor
37. Reactor fuel and coreReactor fuel and core
CRITICALITY
SAFETY
FUEL
FUEL
ICFM = IN-CORE FUEL MANAGEMENT
ICFM CORE
SEVERE
ACCIDENTS
ACCIDENTS
TRANSIENTS
COOLANT FLOW
STABILITYOPERATIONAL
SAFETY LIMITS
IRRADIATION:
MATERIAL DAMAGES
ACTIVATION
HIGH
BURNUP
CLADDING
INTEGRITY CORROSION
WATER
CHEMISTRY
TRANSPORTATION
STORAGE FINAL
REFUELING
SHUTDOWNS
SPENT FUEL
REPOSITORY
STORAGE
THERMAL
MECHANICS
38. Impact Of Additional Nuclear EnergyImpact Of Additional Nuclear Energy
On Greenhouse Gas EmissionsOn Greenhouse Gas Emissions
10,000 MW of additional nuclear capacity can achieve
21% of the President’s GHG intensity reduction goal
Nuclear energy sector commitment:
22 million metric tons of carbon per year
Bush administration’s target:
106 million metric tons of carbon per year
39. Planning of Future safety challengesPlanning of Future safety challenges
physical barriers plant functionsinitiating events
safety management
design analysisintegrity function
operationrisks
1. New fuel designs
and enhanced use
2. Ensurance of integrity of
an ageing reactor circuit
3. Ensurance of containment
integrity and leak-tightness
8. Operational development
with modern technology
9. Plant lifetime management
10. Development of organisational
culture and safety management
12. Risk-informed safety
and operational management
11. Risk analysis
of external effects
6. Automation modernizations
7. Control room modernizations
4. New types of
nuclear power plants
5. Uncertainties associated
with process safety functions
40. Reference GroupsReference Groups
1. Reactor
fuel core
2. Reactor circuit
and structural
safety
3. Containment
and process
safety functions
4. Automation,
control room
IT
5. Organisations
and safety
management
6. Risk-informed
safety management
ad hoc
-ryhmät
ad hoc
-ryhmät
ad hoc
-ryhmät
ad hoc
-ryhmät
ad hoc
groups
Steering
group
41. Organisations and safetyOrganisations and safety
managementmanagement
understanding
cultural
aspects
implementation
of
changes
changes
in
age structure
improved
productivity
efficiency
development
of
technology
changing
procedures
and habits
maintaining
knowledge
and expertise
management
and
decision making
work load
and
wearout
bringing new
technology
into operation
preventing
routine
effects
Theoretical
development
Practical
problems
Pressure
for change
DUAL- Primary coolant is Sodium Water (Low Boiling point)
due to high pressure E.g.. ( PWR)
(NOTE- Water can not be used in fast reactor because of it moderating effect)
1- A nuclear reactor is basically a furnace where the fission of atom can be controlled and heat is put to useful work.
2- In nuclear fission reactor , the condition are such that fission energy is related at controlled rate.
3- The fission energy is converted into heat in reactor, and this hest is utilized to raise the steam directly or indirectly.
CORE- Which contain the fuel element.
MODERATOR- (H2O, D2O,Graphite(Pure C) Which aids the fission process by slowing down the neutrons.
CONTROLLER- (Absorbing Material - Boron, Cadmium, Hafnium, Silver, Indium)
Means for controlling the rate of fission and consequently the power level of the reactor.
REFLECTOR- Which scatter back the neutron escaping from the core. Which decrease the loss of neutron.
It Should have high neutron scattering cross section, low absorption cross section, good slowing down ratio.
( good moderator also may be good reflector)
COOLENT- Which removes the heat generated in the core ( coolant may be water or another gas) .
RADIATION SHIELD- Which protects the operating personal from radiation emitted during fission.
The building containing the reactor is made of reinforced concrete, and the reactor vessel holding the fuel is steel more than a foot thick. The fuel itself is encased in an extremely strong metal alloy that is difficult to breach.
All the equipment and piping are ruggedly constructed and the equipment not in the reactor building itself is housed in areas that are also strongly built. The robustness of the equipment and buildings serves as an additional barrier to explosives or intruders. The used fuel pools and used fuel storage containers are well- protected and also robustly constructed.
In addition, the plants are protected by tough, experienced security forces operating under thorough, sophisticated and well-practiced security plans.
The pressurized water reactor belongs to the light water type: the moderator and coolant are both light water (H2O). It can be seen in the figure that the cooling water circulates in two loops, which are fully separated from one another The primary circuit water (dark blue) is continuously kept at a very high pressure and therefore it does not boil even at the high operating temperature. (Hence the name of the type.) Constant pressure is ensured with the aid of the pressurize (expansion tank). (If pressure falls in the primary circuit, water in the pressurizes is heated up by electric heaters, thus raising the pressure. If pressure increases, colder cooling water is injected to the pressurize. Since the upper part is steam, pressure will drop.) The primary circuit water transferred its heat to the secondary circuit water in the small tubes of the steam generator, it cools down and returns to the reactor vessel at a lower temperature.
Since the secondary circuit pressure is much lower than that of the primary circuit, the secondary circuit water in the steam generator starts to boil (red). The steam goes from here to the turbine, which has high and low pressure stages. When steam leaves the turbine, it becomes liquid again in the condenser, from where it is pumped back to the steam generator after pre-heating
Normally, primary and secondary circuit waters cannot mix. In this way it can be achieved that any potentially radioactive material that gets into the primary water should stay in the primary loop and cannot get into the turbine and condenser. This is a barrier to prevent radioactive contamination from getting out.
In pressurized water reactors the fuel is usually low (3 to 4 percent) enriched uranium oxide, sometimes uranium and plutonium oxide mixture (MOX). In today's PWRs the primary pressure is usually 120 to 160 bars, while the outlet temperature of coolant is 300 to 320 °C. PWR is the most widespread reactor type in the world: they give about 64% of the total power of the presently operating nuclear power plants.
ADVANTAGES OF PRESSURIZED WATER REACTOR:
Water technology well known.
Water is cheap.
Water is very effective moderator of neutron energy
core is compact.
Water has high heat capacity.
Negative temperature coefficient.
Ordinary leakage can be tolerated.
Fission products are contained, not circulated.
Radioactivity of coolant is short-lived if kept pure.
Conversion ratio may be high.
Superheating steam in separately fired superheated is possible.
Appreciable fast fission effect attainable.
DISADVANTAGES OF PRESSURIZED WATER REACTOR:
Water must be highly pressurized to achieve even reasonably high temperature without boiling.
Fuel element fabrication expensive.
The temperature is limited in metallic fuel elements.
Fission product activity in the core builds up to high a level.
Pure hot water is highly corrosive, requires special materials for the primary loop.
Fuel must be at least slightly enriched.
Heat exchanger and control rods required.
Large excess reactivity at operating temperature.
Heat transfer only moderately efficient.
Fuel reprocessing a difficult task.
Rector must be shut down to unload and reload core.
Water would flash to steam in case of rupture of primary loop.
Water reacts with uranium, thorium, and structural metals under certain conditions.
Low thermal heads make heat exchanger, pumps and pipins large.
Hot-channel factors are significant.
A boiling water reactor (BWR) is a light water reactor is a type of nuclear reactor ,in a BWR the steam going to the turbine that powers the electrical generator is produced in the reactor core rather than in steam generators or heat exchanger. There is a single circuit in a BWR in which the water is at lower pressure (about 75 times atmospheric pressure) than in a PWR so that it boils in the core at about 285°C. The reactor is designed to operate with 12–15% of the water in the top part of the core as steam, resulting in less moderation, lower neutron efficiency and lower power density than in the bottom part of the core. In comparison, there is no significant boiling allowed in a PWR because of the high pressure maintained in its primary loop (about 158 times atmospheric pressure).
Advantages
Simple configuration, no steam generator heat-exchangers and associated piping.
Greater thermal efficiency than a PWR operating at the same core temperature.
The reactor vessel and associated components operate at a substantially lower pressure (about 75 times atmospheric pressure) compared to a PWR (about 158 times atmospheric pressure).
Pressure vessel is subject to significantly less irradiation compared to a PWR, and so does not become as brittle with age.
Operates at a lower nuclear fuel temperature.
Disadvantages
Complex operational calculations for managing the utilization of the nuclear fuel in the fuel elements during power production due to "two phase fluid flow" (water and steam) in the upper part of the core (less of a factor with modern computers). More incur nuclear instrumentation is required.
Much larger pressure vessel than for a PWR of similar power, with correspondingly higher cost. (However, the overall cost is reduced because a modern BWR has no main steam generators and associated piping.)
Contamination of the turbine by fission products (less of a factor with modern fuel technology).
Shielding and access control around the steam turbine are required during normal operations due to the radiation levels arising from the steam entering directly from the reactor core. Additionally, additional precautions are required during turbine maintenance activities compared to a PWR.
An Advanced Gas Cooled Reactor (AGR) is a type of nuclear reactor. These are the second generation of British gas-cooled reactors, using graphite as the neutron moderator and carbon dioxide as coolant. The fuel is uranium dioxide pellets, enriched to 2.5-3.5%, in stainless steel tubes. The carbon dioxide circulates through the core, reaching 640°C and a pressure of around 40 bar, and then passes through boiler (steam generator) assemblies outside the core but still within the steel lined, reinforced concrete pressure vessel. Control rods penetrate the moderator and a secondary shutdown system involves injecting nitrogen into the coolant or releasing boron ball shutdown devices.
AGR power stations are configured with two reactors, each reactor with a power output of between 555 MWe and 625 Mwe.
The design of the AGR was such that the final steam conditions at the boiler stop valve were identical to that of conventional power stations. Thus the same design of turbo-generator plant could be used. In order to obtain high temperatures, yet ensure useful graphite core life (graphite oxidizes readily in CO2 at high temperature) re-entrant flow is utilized, ensuring that the graphite core temperatures do not vary too much from those seen in a Magnox station.
The AGR has a good thermal efficiency (electricity generated/heat generated ratio) of about 41%, which is better than modern pressurized water reactors which have a typical thermal efficiency of 34%[1]. This is largely due to the higher coolant outlet temperature of about 640°C practical with gas cooling, compared to about 325°C for PWRs. However the reactor core has to be larger for the same power output, and the fuel burned ratio at discharge is lower so the fuel is used less efficiently, countering the thermal efficiency advantage [2].
The AGR was developed from the Magnox reactor, also graphite moderated and CO2 cooled, a number of which are still operating in UK. The Magnox used natural uranium fuel in metal form and magnesium based cladding.
The original design concept of the AGR was to use a beryllium based cladding. When this proved unsuitable, the enrichment level of the fuel was raised to allow for the higher neutron capture losses of stainless steel cladding. This significantly increased the cost of the power produced by an AGR.
Like the Magnox, CANDU and RBMK reactors, and in contrast to the light water reactors, AGRs are designed to be refuelled without being shut down first, though a number of nuclear safety issues were identified in relation to this and so all AGRs either refuel at part load or when shut down.
The prototype AGR at the Sellafield (Windscale) site is in the process of being decommissioned. This project is also a study of what is required to decommission a nuclear reactor safely.
In heavy water reactors both the moderator and coolant are heavy water (D2O). A great disadvantage of this type comes from this fact: heavy water is one of the most expensive liquids. However, it is worth its price: this is the best moderator. Therefore, the fuel of HWRs can be slightly (1% to 2%) enriched or even natural uranium. Heavy water is not allowed to boil, so in the primary circuit very high pressure, similar to that of PWRs, exists. The main representative of the heavy water type is the Canadian CANDU reactor. In these reactors, the moderator and coolant are spatially separated: the moderator is in a large tank , in which there are pressure tubes surrounding the fuel assemblies. The coolant flows in these tubes only.
The advantage of this construction is that the whole tank need not be kept under high pressure, it is sufficient to pressurize the coolant flowing in the tubes. This arrangement is called pressurized tube reactor. Warming up of the moderator is much less than that of the coolant; its is simply lost for heat generation or steam production. The high temperature and high pressure coolant, similarly to PWRs, goes to the steam generator where it boils the secondary side light water. Another advantage of this type is that fuel can be replaced during operation and thus there is no need for outages.
The other type of heavy water reactors is the pressurized heavy water reactor (PHWR). In this type the moderator and coolant are the same and the reactor pressure vessel has to stand the high pressure.
The heavy water reactors give 5.3% of the total NPP power of the world, however 13.2% of the under construction nuclear power plant capacity is given by this type. One reason for this is the safety of the type. and the other is the high conversion factor, which means that during operation a large amount of fissile material is produced from U-238 by neutron capture.