Pp manish on nuclear power plant


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  • SIGLE- Coolant is either steam or hot gasses
  • 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.
    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.
    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).
    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.
    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.
  • Pp manish on nuclear power plant

    1. 1. ( PG/ICE/6101/06 )
    2. 2. 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
    3. 3. A Nuclear Power PlantA Nuclear Power Plant
    4. 4. NeedsNeeds ofof NuclearNuclear PowerPower PlantsPlantsgrowing energy demandsgrowing energy demands unpredictable fossil fuel costs andunpredictable fossil fuel costs and continued need for clean energy.continued need for clean energy.
    5. 5. Nuclear Energy:Nuclear Energy: A Unique Value PropositionA Unique Value Proposition Safe, Reliable, Competitive Electricity Forward Price Stability Clean Air, Carbon-Free Value
    9. 9. 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
    10. 10. 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
    11. 11. 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
    12. 12. 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
    13. 13. 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
    14. 14. 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.
    15. 15. 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
    16. 16. 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
    17. 17. 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.
    18. 18. 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.
    20. 20. 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
    21. 21. 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
    22. 22. 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
    23. 23. 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)
    24. 24. 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
    25. 25. 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
    26. 26. Pressurized water reactorPressurized water reactor
    27. 27. 1 Reactor vessel 8 Fresh steam 14 Condenser 2 Fuel elements 9 Feedwater 15 Cooling water 3 Control rods 10 High pressure turbine 16 Feedwater pump 4 Control rod drive 11 Low pressure turbine 17 Feedwater pre-heater 5 Pressurizer 12 Generator 18 Concrete shield 6 Steam generator 13 Exciter 19 Cooling water pump 7 Main circulating pump Pressurized water reactorPressurized water reactor
    28. 28. Boiling water reactor
    29. 29. Advanced Gas Cooled Reactor (AGR)
    30. 30.   Heavy Water Reactor/candu
    31. 31. The History of Nuclear EnergyThe History of Nuclear Energy DeploymentDeployment
    32. 32. 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
    34. 34. 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
    35. 35. 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
    36. 36. 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
    37. 37. 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
    38. 38. S U M A R Y O F N U C L E A R P O W E R P L A N T
    39. 39. Nuclear Heat Mechani cal Electrical