Nuclear Fundamentals - UNM - New Mexicos Flagship …核基础-大学-新墨西哥的旗舰….ppt

Nuclear Fundamentals Part I Unleashing the Power of the Atom Objectives Purpose/advantages of nuclear power Atomic structure, notation, and vocabulary Mass-to-energy conversions (how to get blood from a turnip) Basics of nuclear fission Controlling fission and nuclear reaction rates Introduction Early/alternate naval boilers used oil, coal, or wood - nuclear fission is viable option Advantages: Long life of nuclear core Unlimited endurance/range No need for outside material (air) Less logistical support Carrier carries more weapons, aircraft, fuel Basic Atomic Structure Nucleus: the core of an atom Proton: positive (+) charge primary identifier of an element mass: 1.00728 amu Neutron: no charge usually about the same number as protons mass: 1.00866 amu Electron: orbits about the nucleus Negative (-) charge Mass: 0.0005485 amu (over 1000’s times smaller) Help determine how element reacts chemically Basic Atomic Structure Atomic Structure Isotopes: atoms which have the same atomic number but a different atomic mass number (ie: different number of neutrons) Standard Notation: AZX where: X = element symbol (ie: H for hydrogen) A = atomic mass number (p’s and n’s) Z = atomic number (p’s only) Standard Notation the Periodic Table 23892U - U: uranium 238: p’s + n’s 92: p’s 146 n’s Mass to Energy Remember conservation of mass energy Mass of an element/isotope is less than individual masses of p’s, n’s, and e’s - difference is called mass defect Einstein’s Theory: E = mc2 or DE = Dmc2 Energy released if nucleus is formed from its components is binding energy (due to mass defect) Blood from a Turnip Mass to Energy Mass Defect = mass of reactants - mass of products Conversion to energy 1 amu = 931.48 MeV Fission uses this principle - large isotopes break into pieces releasing energy which can be harnessed Fission Def’n: splitting of an atom 23592U is fuel for reactor Relatively stable Likely to absorb a neutron (large sa) 23692U