堆工原理UNIT 3.ppt

sdasdasd  PRINCIPLE OF REACTOR ENGINEERING核 反 应 堆 工 程 原 理PU SHENGDI 2007.08  UNIT 3  NUCLEAR FISSION UNIT 3 NUCLEAR FISSION NEUTRON – NUCLEI REACTIONS NUCLEAR FISSION New Words and Phrases neutron - nuclei reaction 中子－核反应 Scattering 散射 capture 俘获 Fission 裂变 fissile nuclides 易裂变核素 fissionable nuclides 可裂变核素 fertile nuclides 可转换核素 million electron volt (MeV) 百万电子伏特 fast neutron 快中子 slow (thermal) neutron 慢（热）中子 fission fragment 裂变碎片 fission produc 裂变产物 New Words and Phrases cross section 截面 microscopic cross section 微观截面 macroscopic cross section 宏观截面 chain reaction 链式反应 critical mass 临界质量 effective multiplication factor 有效增值因子 Reactivity 反应性 Critical 临界 subcritical 次临界 supercritical 超临界 finite size 有限尺寸 UNIT 3 NUCLEAR FISSION NEUTRON – NUCLEI REACTIONS  1. The neutron-nuclei reactions fall into three general categories, namely, scattering, capture, and fission. In scattering reactions the net result is the exchange of energy between a neutron and a nucleus. UNIT 3 NUCLEAR FISSION scattering Scattering can be either elastic or inelastic In a elastic collision, the kinetic energy of the neutron is decreased whereas that of the nucleus is increased correspondingly, because neutrons generally have a higher kinetic energy than do atomic nuclei. In inelastic Scattering the kinetic energ