Nuclear Energy Short history 1930, atom made up of neutrons and protons 1.67X10-27kg 1840 times heavier than electron A Z N Mass Atomic(proton) Number of number number neutrons ME=Am.c2 复旦大学环境科学与工程系 Department of Environmental Science and Engineering, Fudan University
Nuclear Energy Short History 1930, atom made up of neutrons and protons. 1.67×10-27 kg 1840 times heavier than electron A = Z + N Mass number Atomic (proton) number Number of neutrons ∆E=∆m·c2
Nuclear Energy Chemical reactions: a few eV Nuclear fission reactions: hundreds of mev per atom Pushed apart by Coulomb repulsion, the positively charged energetic fission fragments move away form the site of the fission reaction and come to stop in the surrounding material. In this way their kinetic energy very quickly becomes heat energy in the material 复旦大学环境科学与工程系 Department of Environmental Science and Engineering, Fudan University
Nuclear Energy Chemical reactions: a few eV Nuclear fission reactions: hundreds of MeV per atom Pushed apart by Coulomb repulsion, the positively charged energetic fission fragments move away form the site of the fission reaction and come to stop in the surrounding material. In this way their kinetic energy very quickly becomes heat energy in the material
Nuclear Energy Neutron Barium Gamma Figure 6. 1 Three steps in the neutron-induced fission of 235U. The combination of a neutron and 235U forms 236U in a highly excited state, that promptly fissions into two lighter nuclei, emitting neutrons and gamma rays in the process The two fragments are called fission products and they carry off about 160 Mev of kinetic energy from the fission reaction 复旦大学环境科学与工程系 Department of Environmental Science and Engineering, Fudan University
Nuclear Energy The two fragments are called fission products, and they carry off about 160 MeV of kinetic energy from the fission reaction
Nuclear Energy Growing rate, release a large amount of energy in a short time f(=a If the rate of the chain reaction could be controlled by some means so that it was steady, rather than increasing, then one would have a source of heat energy appropriate to drive an electric generator World War Il, Nazi military occupation of much of Europe immediately following the discovery of fission, the initial efforts to exploit this new phenomenon centered on producing a nuclear weapon rather than a nuclear power reactor 复旦大学环境科学与工程系 Department of Environmental Science and Engineering, Fudan University
Nuclear Energy Growing rate, release a large amount of energy in a short time. If the rate of the chain reaction could be controlled by some means so that it was steady , rather than increasing, then one would have a source of heat energy appropriate to drive an electric generator. World War II, Nazi military occupation of much of Europe immediately following the discovery of fission, the initial efforts to exploit this new phenomenon centered on producing a nuclear weapon rather than a nuclear power reactor. x f (x) = a
Nuclear Energy The first nuclear reactor was assembled at the university of Chicago in 1942 by Enrico Fermi and co-worker. They successfully demonstrated a chain reaction, even though it was at a very low power level about 200 watts Abundance Manhattan Project 235 Los Alamos. New mexico 20143 0.70 Oak ridge, Tennessee, etc 238 920146 99.39 3 Nuclear bomb Critical Mass 15kg 23SU Ist, test in New Mexico, July, 1945 5kg 239Pu Hiroshima nagasaki, august, 1945 复旦大学环境科学与工程系 Department of Environmental Science and Engineering, Fudan University
Nuclear Energy The first nuclear reactor was assembled at the University of Chicago in 1942 by Enrico Fermi and co-worker. They successfully demonstrated a chain reaction, even though it was at a very low power level about 200 watts. Manhattan Project Los Alamos, New Mexico; Oak Ridge, Tennessee, etc. Critical Mass 15kg 235U, 5kg 239Pu 235 92U143 238 92U146 0.7% 99.3% 3 Nuclear bomb 1st, test in New Mexico, July, 1945. Hiroshima Nagasaki, August, 1945 Abundance