Topic 5 The Fires of Nuclear Fission - Youngstown State 话题5核裂变-最近状态的火灾

1、.15Chemistry 500Dr. Hunters ClassTopic 5.Chemistry 500: Chemistry in Modern LivingTopic 5: The Fires of Nuclear FissionAtomic Structure, Nuclear Fission and Fusion, and Nuclear WeaponsChemistry in Context, 2nd Edition: Chapter 8, Pages 245-280Chemistry in Context, 3rd Edition: Chapter 7, Pages 265-3

2、04Outline Notes by Dr. Allen D. Hunter, YSU Department of Chemistry, Ó2000.Outline 5AATOMIC AND NUCLEAR STRUCTURE35BFISSION AND FUSION55CNUCLEAR REACTIONS AND CHAIN REACTIONS65DNUCLEAR FISSION REACTORS75ERADIATION AND RADIOACTIVE DECAY105FNUCLEAR POWER AND THE WORLD125GNUCLEAR BOMB DESIGN135A A

3、tomic and Nuclear StructureØ Atomic Structure:Ø NucleusØ Electron CloudØ Nuclear Structure:Ø Neutrons and ProtonsØ Strong Nuclear Force vs. Electrostatic ForceØ Rubber Baggie ModelØ IsotopesØ Atomic Number Ø Determined by number of protonsØ Mass

4、 NumberØ Equals the total number of protons and neutronsØ Ask Students: Give the number of protons and the number of neutrons for each of the following isotopes or give the atomic symbol, as requiredØ Group Activity Ø 32 protons and 37 neutrons ÞØ 17 protons and 16 neut

5、rons Þ5B Fission and FusionØ Fission Reactions are nuclear reactions that split the nucleus into smaller fragmentsØ Fusion Reactions are nuclear reactions that join two units to form a larger nucleusØ These nuclear reactions can be extremely exothermicØ They produce large am

6、ounts of heatØ For example 235U fission Þ energy equivalent to 33,000 tons of TNT from 1 kg of UraniumØ This energy is produced via the conversion of mass to energyØ Einstein Þ E = m c25C Nuclear Reactions and Chain ReactionsØ Involve the splitting or combining of nucle

7、i and fragmentsØ They can be balanced much like chemical reactionsØ Chain ReactionsØ Graphics from Text: Figure 8.3 in 2nd Edition and 7.2 in 3rd Edition, Chain Reaction DiagramØ Average of 2 to 3 neutrons per fissionØ Induced nuclear fission5D Nuclear Fission ReactorsØ

8、 Graphics from Text: Figure 7.3 in 3rd Edition, Diagram of a nuclear power plantØ Roles of Major ComponentsØ Fuel RodsØ Moderator (Thermal Neutrons)Ø Control RodsØ Steam system Ø PipingØ TurbinesØ Cooling towers / heat exchangersØ Graphics from Text: Figu

9、re 7.4 in 3rd Edition, Diagram of fuel assembly in nuclear power plantØ Comparison of various reactor typesØ Key variablesØ Level of enrichmentØ Moderator typeØ Cooling fluidØ Pressurized light water reactorØ US NavyØ Heavy water reactor, CANDUØ Liquid me

10、tal cooled reactorØ Graphite moderated / Helium Cooled reactorØ Natural ReactorsØ What prevents melt downsØ Active control systemsØ RedundancyØ Mechanical errorsØ Brittle piping (alloys), Welding, Pumps Ø Human errors Ø Homer SimpsonØ Passive control

11、 systemsØ Energy densityØ No-maintenance pilesØ What happened at ChernobylØ Breeder Reactors 5E Radiation and Radioactive DecayØ Graphics from Text: Table 8.1 in 2nd Edition and 7.1 in 3rd Edition, Radioactive emissionsØ Types of RadiationØ Alpha particles, Helium

12、nucleiØ Beta particles, electronsØ Gamma rays, high energy photonsØ NeutronsØ Variations in penetrating powerØ DosesØ Lethal vs. typicalØ The controversy about low dosesØ Graphics from Text: Table 8.4 in 2nd Edition and Figure 7.10 in 3rd Edition, US Backgroun

13、d Radiation SourcesØ Radioactive DecayØ Half life of an isotope for spontaneous decayØ Ranges of half lives in common isotopesØ Graphics from Text: Figure 8.9 in 2nd Edition and 7.12 in 3rd Edition: Radioactive decay curve for 239Pu5F Nuclear Power and the WorldØ Graphics fr

14、om Text: Table 8.5 from 2nd Edition and Table 7.4 from 3rd Edition, Nuclear Power Statistics for Selected CountriesØ Graphics from Text: Figure 8.10 from 2nd Edition and Figure 7.19 from 3rd Edition, Percentage of Electrical Power Generated from Nuclear Reactors for Selected CountriesØ Ask

15、 Students: Develop some reasons why the differences between different countriesØ Group Activity5G Nuclear Bomb DesignØ Critical MassØ 15 to 18 kg of 235UØ Crude Fission bomb designØ Tube cannonØ Collapsing shellØ Crude Fusion bomb designØ Miniaturization of bo

16、mbsIndex of Vocabulary and Major Topics:Ó2000, Dr. Allen D. Hunter, Department of Chemistry, Youngstown State University2235U5, 13239Pu11AActive control systems9Alpha particles10Ask Students4, 12Atomic and Nuclear Structure3Atomic Number3Atomic Structure3atomic symbol4BBeta particles10Breeder R

17、eactors9CCANDU8Chain Reaction Diagram6Chain Reactions6Chernobyl9Control Rods7Cooling fluid8Cooling towers7Critical Mass13DDoses10EE = m c25Einstein5Electron Cloud3electrons10Electrostatic Force3Energy density9enrichment8exothermic5Ffission5Fission and Fusion5Fission bomb design13Fission Reactions5fu

18、el assembly in nuclear power plant7Fuel Rods7Fusion bomb design13Fusion Reactions5GGamma rays10Graphics from Text6, 7, 10, 11, 12Graphite moderated / Helium Cooled reactor8Group Activity4, 12HHalf life11heat exchangers7Heavy water reactor8Helium nuclei10Homer Simpson9IInduced nuclear fission6isotope11isotopes4Isotopes3LLiquid metal cooled reactor8low doses10MMajor Components7Mass Number3mass to energy5melt downs9Moderator7, 8NNatural Reactors8Neutrons3, 10neutrons per fission6Nuclear Bomb Design13Nuclear Fission Reactors7Nuclear Power and the World12nuclear power plant