Eight Sessions 1. Pressurized Water Reactor 2. Quiz, Thermodynamics & HTFF 3. Quiz, Physics & Chemistry 4. Exam #1, Electrical Concepts & Systems 5. Quiz, Materials Science 6. Quiz, Strength of Materials - Statics 7. Quiz, Engineering Disasters 8. Exam #2, Engineering Seminar, Education & Careers 1
The Atom Nucleus Electrons in Orbitals Not to scale! 2
Atom Nucleus Nucleons o Protons o Neutrons Electrons Positive Electrical Charge No Electrical Charge Negative Electrical Charge The mass of an electron is approximately 1 1836 of a proton. 3
What determines an Element? For example: Oxygen or Gold? Number of Protons in the Nucleus Oxygen Gold O Au 8 Protons 79 Protons Uranium U 92 Protons 4
Atomic Number Number of Protons Atomic Mass Total of Number of Nucleons = Protons + Neutrons 56 26 Fe 26 Fe 56 56 Fe 26 5
Chemical Reactions Only have to do with the electron shell Gaining electrons Giving electrons Sharing electrons Not the Nucleus! 6
Electrical Charge of an atom Neutral: # of electrons = # of protons If lose an electron +1 charge If lose two electrons +2 charge If gain an electron: -1 charge + + + 7
Ion An atom with a net electrical charge. Due to having less or more electrons than protons. Positive ions Negative ions 8
Periodic Table 9
Two atoms Isotope Two nuclei of the same element Always have the same number of protons But they can have different numbers of neutrons That makes them different isotopes of the same element 56 54 55 56 57 58 59 60 26 Fe 10
What holds the nucleus together? Like Charges Repel Electro Static Force + + + + Strong Nuclear Force Attraction - Very close range 11
Some Isotopes are stable and some are radioactive Stable: No radioactive decay Radioactive decay alpha decay beta decay alpha particle beta particle 12
Line of Stability 13
Chart of the Nuclides 14
Reactor Physics Fission Process What happens to neutrons? Multiplication Factor Critical, Supercritical, Subcritical 15
Fuel in the Reactor Uranium: Atomic number 92 Natural Uranium mostly U 238 238 92 U Best isotope for fission is U 235 Only about 0.7% in ore Must be enriched to about 3% or more 16
Pressurized Water Reactor Plant Secondary Plant Pzr G T S/G /G Rx Cond Primary Plant 17
Reactor 18
Top View of Reactor Core Coolant outlet Coolant inlet Fuel Assemblies 19
Fuel Assembly Fuel Rod Tubes Coolant Channels Control Rod Tubes 20
Fuel Fuel Pellets Rod Tube Fission Heat Coolant Flow 21
Conduction through Fuel Rod Tube Q K T T 2 T 1 22
Fission process and heat generation and transfer 23
U 235 Nucleus absorbs a neutron 24
Prompt Neutrons & Gammas 25
Fast Neutron Slowing Down H 2 O Moderator Thermal Neutron 26
Chain Reaction 27
Heat Deposition by fission fragments Kinetic Energy Electrostatic Fields Structural Atoms Vibrate more Region of higher temperature 28
29
Heat Transfer from Fuel Rod Tube Q K T T 2 T 1 Conduction Radiation Convection 30
Reactor Power neutrons U 235 fissions Heat output Leak Out Absorbed in non-fuel material 31
Prompt Neutrons Delayed Neutrons Slowing Down Moderator Thermal Neutrons Chain Reaction Neutron Flux 32
What happens to neutrons? Absorbed in Fuel Absorbed in non-fuel material Leak out 33
Neutron Population Generation to Generation Increasing? Decreasing? Staying the same? A reactor is a multiplying medium for neutrons. Multiplication Factor 34
Multiplication Factor, K k = k = Number of fissions in one generation Number of fissions in preceding generation Number of neutrons in one generation Number of neutrons in preceding generation 35
Multiplication Factor, K 100 neutrons in the core now. A chain reaction of fissions is in progress. After some cause fission, how many neutrons in the next generation? If K=1.0 100 x 1.0 = 100 neutrons Critical If K=1.1 100 x 1.1 = 110 neutrons Super-critical If K=0.9 100 x 0.9 = 90 neutrons Sub-critical 36
Multiplication Factor K>1 K=1 K<1 Fraction of neutrons absorbed in fuel, absorbed in non-fuel, leak out Supercritical, Critical, Subcritical 37
Muliplication Factor Depends on: Design Materials: Structural & Fuel Geometry: Shape and Size During Operation Control Rods Coolant Temperature 38
Control Rods Shim the Rods in More neutrons absorbed in the Control Rods Less neutrons to cause fission Multiplication factor goes down 39
Coolant Temperature Moderator Density Neutron Leakage Reactor 40
Neutron born Coolant Temperature Moderator Density Neutron Leakage Multiplication Factor goes up H 2 O Moderator Neutron Leaks out 41
Six Factor Formula k fl f L th Materials: Fuel & non-fuel Leakage 42
Multiplication Factor K>1 K=1 K<1 Fission rate Reactor Power Thermal Output Fraction of neutrons absorbed in fuel, absorbed in non-fuel, leak out Supercritical, Critical, Subcritical 43
Decay Heat 44
Chemistry Dissolve in water NaCl Atomic Masses: 23, 35 Molecular Weight= 23+35=58 45
H 2 O Na + Cl - - + + - + - + - + -
Concentration [something]=10-4 Moles per liter 47
Concentration Molarity = gram-moles of solute per liter of solution Mole? Gram-Mole? 6.02 x 10 23 Molecular Weight in Grams One Gram-Mole of NaCl = 58 grams 48
Self Ionization of Water Even in pure water 49
H 2 O Self Ionization of Water - + - + - + - +
Self Ionization of Water - + + OH- H+ H 3 O+ Hydroxyl Hydrogen Ion Hydronium 51
Self Ionization of Water Concentration of OH - and H 3 O + in pure water 2H O H O 2 3 OH [OH - ]=10-7 [H 3 O + ]=10-7 Ionization Constant for water = [][]=10-14 52
ph The negative log of hydronium ion concentration. 53
ph and poh ph log [ H 10 ] poh log [ OH 10 ] 54
Review of Logarithms log N b y b y N Take the logarithm of both sides 55
Review of Logarithms The logarithm of a number to a given base, is the power to which the base must be raised to produce the number. log N b y b y N 56
Review of Logarithms log 10 N y 10 y N Take the logarithm of both sides 57
ph and poh ph log [ H 10 ] poh log [ OH 10 ] 58
ph and poh Ionization Constant for water = [][]=10-14 ph + poh = 14 59
Acids and Bases Neutral Pure Water has ph of 7 [H 3 O + ]=10-7 Acids ph < 7 Bases ph > 7 60
Conductivity of water ph NaCl 61