Nuclear materials
Nuclear Materials
Words 1 ℃ admium n镉 cobalt n.钴 mercury n水银 nitrogen n氮气 uranium n.铀 plutonium n钚 zIrconium n 锆 beryllium n.铍 boric acid,n.硼酸 boron n.硼 carbide n碳化物 chromium n.铬 dioxide n二氧化物 eutectic a.共晶的 hafnium n.铪(拼音ha) hydrocarbon n碳氢化合物 gadolinium n.钆(拼音ga) inert a.惰性的
Words 1 Cadmium n. 镉 cobalt n. 钴 mercury n. 水银 nitrogen n. 氮气 uranium n. 铀 plutonium n. 钚 zirconium n. 锆 beryllium n. 铍 boric acid, n. 硼酸 boron n. 硼 carbide n. 碳化物 chromium n. 铬 dioxide n. 二氧化物 eutectic a. 共晶的 hafnium n. 铪 (拼音ha) hydrocarbon n. 碳氢化合物 gadolinium n.钆 (拼音ga) inert a. 惰性的
Words 2 Magnesium n.镁 Magnox n镁诺克斯合金 metallurgy n冶金 nickel n镍 oxide n.a.氧化物(的) oxidize v.使氧化,生锈 paraffin n.石蜡 WaXn.石蜡 pellet n.燃料芯块,片 phase n.相 potassium n钾 pyrolitic,a.热解的 silicon n.硅 sodium n钠 tin n 锡 lead n.铅 zircaloy n锆合金 toxic a.有毒性的
Words 2 Magnesium n. 镁 Magnox n. 镁诺克斯合金 metallurgy n. 冶金 nickel n. 镍 oxide n. a. 氧化物(的) oxidize v. 使氧化，生锈 paraffin n. 石蜡 wax n. 石蜡 pellet n. 燃料芯块，片 phase n. 相 potassium n. 钾 pyrolitic, a. 热解的 silicon n. 硅 sodium n. 钠 tin n. 锡 lead n. 铅 zircaloy n. 锆合金 toxic a. 有毒性的
Words 3 Allotropic a同素异型的 anisotropic a各向异性 ceramic a.陶瓷的 component n.元素,组成部分 conductivity n.传导率 corrosion n.腐蚀 erosion n冲蚀 crack n开裂 stress corrosion cracking(SCC,n.应力腐蚀开裂 criticality n.临界(性,状态) crystalline a.晶体状的 diffuse n.扩散 dimensional a.尺寸的 distortion n变形 dose n剂量 trap n.阱,收集器 viscosity n.粘性
Words 3 Allotropic a. 同素异型的 anisotropic a.各向异性 ceramic a. 陶瓷的 component n. 元素，组成部分 conductivity n. 传导率 corrosion n. 腐蚀 erosion n.冲蚀 crack n. 开裂 stress corrosion cracking (SCC), n. 应力腐蚀开裂 criticality n. 临界(性，状态) crystalline a. 晶体状的 diffuse n. 扩散 dimensional a. 尺寸的 distortion n. 变形 dose n. 剂量 trap n. 阱，收集器 viscosity n. 粘性
Words 4 enrich v.富集,浓缩 exposure n辐照 fabricate v.制造,生产 fraction n分数,部分 homogeneous n.均匀的 inhalation n吸入 integrity n完整性 liab|ea.易于.的 moist a.湿的 pre-eminent a.优秀的 retain v.保持,保留 saturation n.饱和 self-annealing自退火 sublime v.升华 susceptible a敏感的 thermodynamic a.热力学的 transition n.转变
Words 4 enrich v. 富集，浓缩 exposure n. 辐照 fabricate v. 制造，生产 fraction n. 分数，部分 homogeneous n. 均匀的 inhalation n. 吸入 integrity n. 完整性 liable a. 易于…的 moist a. 湿的 pre-eminent a. 优秀的 retain v. 保持，保留 saturation n. 饱和 self-annealing 自退火 sublime v. 升华 susceptible a.敏感的 thermodynamic a. 热力学的 transition n. 转变
1 Fuels
1. Fuels
1.1 ranium Uranium in one form or another is by far the most common fuel material for nuclear reactors.不同形式的铀是反应堆中最常用的一种燃 料 by far是加重语气,说明了 the most的程度。 It can be used either as pure uranium, a metal, or as compound such as uranium dioxide uo2 or uranium carbide uc.它可以或者作为 纯铀金属状态使用,或者以化合物的形式,例如二氧化铀或碳化铀,来使 用。 Uranium is a rather soft and ductile metal which oxidizes readily in air and water at high temperature铀是一种很软而且延展性很好的金属, 它在高温时容易在空气和水中氧化 Its melting point is 1133C. It exists in one of three allotropic forms depending on its temperature. These different forms are called the alpha, beta or gamma phase, and changes from one phase to another due to temperature changes are accompanied by density changes.其熔化温度位1133°C,根据其温度,它以三种同素异形体之 的形态存在,这些形态为α,β或者γ相,并且它们之间因温度变化而相互 转化时会伴有密度变化
1.1 Uranium Uranium in one form or another is by far the most common fuel material for nuclear reactors. 不同形式的铀是反应堆中最常用的一种燃 料。 by far是加重语气，说明了the most的程度。 It can be used either as pure uranium, a metal, or as compound such as uranium dioxide UO2 or uranium carbide UC. 它可以或者作为 纯铀金属状态使用，或者以化合物的形式，例如二氧化铀或碳化铀，来使 用。 Uranium is a rather soft and ductile metal which oxidizes readily in air and water at high temperature. 铀是一种很软而且延展性很好的金属， 它在高温时容易在空气和水中氧化。 Its melting point is 1133oC. It exists in one of three allotropic forms depending on its temperature. These different forms are called the alpha, beta or gamma phase, and changes from one phase to another due to temperature changes are accompanied by density changes. 其熔化温度位1133oC，根据其温度，它以三种同素异形体之一 的形态存在，这些形态为a，b或者g相，并且它们之间因温度变化而相互 转化时会伴有密度变化
Alpha phase uranium has a density of 19g/cm3 and a thermal conductivity which varies from 25W/mk at 25oc to 42W/mk at 665oC The transition from alpha to the beta phase takes place at 665oc and is accompanied by dimensional changes in crystalline structure of the uranium, expansion along one axis and contraction along the others. Mae b相的转变发生在665c,并伴随铀晶体结构尺寸变化,沿一个轴伸长,另一个轴 缩短。 To avoid distortion due to these anisotropic dimensional changes 665oC is considered to be the maximum operating temperature of uranium.为了防止 由于各向异性尺寸变化所造成的变形,665°c被认为是金属)铀的最高工作温度。 Metallic uranium is also very susceptible to radiation damage which produces dimensional changes and swelling above about450.金属铀也 非常容易受到辐照损伤,在大约450c以上产生尺寸变化和肿胀 Consequently high burnups of metallic uranium fuel are not possible n the British gascooled Magnox Reactors, which are the principal users of this type fuel, the burnup is limited to about3500MWdt.在主要采用这种燃料 的英国美诺克斯气冷堆中,其燃耗被局限在3500MWd/t
Alpha phase uranium has a density of 19g/cm3 and a thermal conductivity which varies from 25W/mK at 25oC to 42W/mK at 665oC. The transition from alpha to the beta phase takes place at 665oC and is accompanied by dimensional changes in crystalline structure of the uranium, expansion along one axis and contraction along the others. 从a到 b相的转变发生在665oC，并伴随铀晶体结构尺寸变化，沿一个轴伸长，另一个轴 缩短。 To avoid distortion due to these anisotropic dimensional changes 665oC is considered to be the maximum operating temperature of uranium. 为了防止 由于各向异性尺寸变化所造成的变形，665oC被认为是(金属)铀的最高工作温度。 Metallic uranium is also very susceptible to radiation damage which produces dimensional changes and swelling above about 450oC. 金属铀也 非常容易受到辐照损伤，在大约450oC以上产生尺寸变化和肿胀。 Consequently high burnups of metallic uranium fuel are not possible. In the British gascooled Magnox Reactors, which are the principal users of this type fuel, the burnup is limited to about 3500MWd/t. 在主要采用这种燃料 的英国美诺克斯气冷堆中，其燃耗被局限在3500MWd/t
To summarize, the low operating temperature, susceptible to radiation damage and low permissible burnup of uranium are serious disadvantages to its choice as a reactor fuel, and account for(说明,解释) its very limited use Uranium dioxide UO,, is a black powder which can be fabricated by cold pressing(冷压) and sintering(烧结) at high temperature to produce small cylindrical(圆柱体的) pellets, and in this form it is by far the most common material for the fuel of commercial reactors In this ceramic form UO, has good stability at high temperature and good resistance to radiation damage which enables it to be used to high burnups The melting point(熔点)is2865° C and the theoretical density(理论密度)is 1096gcm3, although in practice(实际上) the density of Uo2 pellets produced as described above is about 10g/cm3. The thermal conductivity is low, being about 2. 5W/mk in the temperature range from1000to2000c, however this low thermal conductivity(热导率) is compensated for( *hl)by the very high melting point which permits high maximum fuel temperatures
To summarize, the low operating temperature, susceptible to radiation damage and low permissible burnup of uranium are serious disadvantages to its choice as a reactor fuel, and account for (说明，解释) its very limited use. Uranium dioxide UO2 is a black powder which can be fabricated by cold pressing (冷压) and sintering (烧结) at high temperature to produce small cylindrical (圆柱体的) pellets, and in this form it is by far the most common material for the fuel of commercial reactors. In this ceramic form UO2 has good stability at high temperature and good resistance to radiation damage which enables it to be used to high burnups. The melting point (熔点) is 2865oC and the theoretical density (理论密度) is 10.96g/cm3 , although in practice (实际上) the density of UO2 pellets produced as described above is about 10g/cm3. The thermal conductivity is low, being about 2.5W/mK in the temperature range from 1000 to 2000oC, however this low thermal conductivity (热导率) is compensated for (补偿) by the very high melting point which permits high maximum fuel temperatures
Uranium dioxide does not react with water at high temperature, a very valuable characteristic as otherwise cladding failures in water cooled reactors would lead to serious reactions.二氧化铀在高温下不与水发生反应,(这是)一 个重要的特性,否则水冷堆的包壳破损将导致严重的反应。 It can retain a large fraction of the gaseous fission products at temperatures below 1000oC, but as the fuel temperature at the center of a pellet is likely to be greatly in excess of this value, provision(iB)must made for fission product gas release.在1000度以下,它可以保持裂变气体产物的一大部分, 但是由于燃料芯块中心的温度可能超过这个温度,必须采取预防 措施防止气体释放。 This is usually done by having an empty space at the top of each fuel tube into which the gases can diffuse.这通常是通过 在燃料棒上部留出一个空间来使气体向其扩散的方式来实现
Uranium dioxide does not react with water at high temperature, a very valuable characteristic as otherwise cladding failures in water cooled reactors would lead to serious reactions. 二氧化铀在高温下不与水发生反应，(这是)一 个重要的特性，否则水冷堆的包壳破损将导致严重的反应。 It can retain a large fraction of the gaseous fission products at temperatures below 1000oC, but as the fuel temperature at the center of a pellet is likely to be greatly in excess of this value, provision (预防) must made for fission product gas release. 在1000度以下，它可以保持裂变气体产物的一大部分， 但是由于燃料芯块中心的温度可能超过这个温度，必须采取预防 措施防止气体释放。 This is usually done by having an empty space at the top of each fuel tube into which the gases can diffuse. 这通常是通过 在燃料棒上部留出一个空间来使气体向其扩散的方式来实现
