3. Parts under stress 4. Human error
(2) According to the text, the most likely source of troubles in a nuclear comes from 1. Core of the reactor 2. Conventional components 3. Parts under stress 4. Human error
第3章 句子翻译－举例
3.1. Which 从句
(1) The atoms of all elements, which at one time were thought to be the fundamental particles of nature, consist of numbers of three more fundamental particles-protons, neutrons and electrons. 曾经被认为是自然界中基础粒子的原子是由多个更基础的粒子组成－质子、中子和电子。
(2) The force of electrostatic repulsion 静电斥力 between like
charges, which varies inversely as the square of their separation, would be expected to be so large that nuclei could not be formed. 在相同的电荷之间的静电斥力与它们之间的距离成反比，这个力如此之大以至于原子核无法形成。
(3) Different isotopes of an element behave identically as far as their chemistry is concerned, whichis not surprising as chemical bonds exist
between electrons. (非限定性定语从句) 仅考虑化学性质，一个元素的不同同位素都有相同的性质，这一点并不奇怪，因为化学键仅存在于电子之间。
(4) Isotopes differ from one another physically in that the masses and other characteristics of their nuclei are different, which is to be expected as it is in the nuclei that the difference between two isotopes lies. (非限定性，修饰前面的句子) 同位素之间的物理特性是不同的，由于两个同位素的差别是在原子核内，因此可以预计到它们的原子核的质量和其它特性都会有差别。
(5) The total new mass produced is twice the mass-energy of the electron, 2(0.51)=1.02MeV,which means that the reaction can occur only if the gamma ray has at least this amount of energy. (非限定性) 所产生的总的新质量是两倍电子的质能2(0.51)=1.02MeV，这意味着仅当伽马射线最少具有这个能量时这个反应才可能发生。
(6) Water has excellent neutron slowing down properties which enable water moderated reactors to have much more compact cores than are possible in other types of thermal reactors
(7) The reactor vessel is located within a deep pit, which can be flooded when the reactor is shutdown. 反应堆容器被放置在一个深坑中，这个坑在反应堆停堆后可以被水淹没。
(8) The cooled water leaving the steam generators is returned to the core by a large circulating pump, and the steam produced flows to a
turbine, which drives the electrical generator. 冷却后的水离开蒸汽发生器由一个巨大的循环泵送回堆芯，产生的蒸汽流到驱动发电机的汽轮机。
3.2. 介词+which，如in which等
(1) The atom consists of nucleus in which all the positively charged protons and uncharged neutrons are closely grouped together, and a number of negatively charged electrons moving in orbital paths around the nucleus. 原子包含一个原子核，其中带正电的质子和不带电的中子紧密聚集在一起，一定数量带负电的电子沿着轨道绕核运动。
(2) The explanation is to be found in the principle of the equivalence of mass and energy in which (修饰principle) Einstein stated that mass and energy are different forms of the same fundamental quantity. 从质量和能量的等效原理中可以找到解释，在这一原理中，爱因斯坦证明了质量和能量时同一基本量的两个不同形式。 (3) Consequently alpha particles have a short and well-defined range in matter which depends on their energy and the density of the
material through which they pass. 因此a粒子在物质中有一个短而明确的穿透范围，该范围取决于其能量和穿过物质的密度。
(4) The values for the range of 5MeV alpha particles in air and
aluminum are about 3.5cm and 0.0025cm respectively, from which it is evident (to see) that alpha particles can be easily stopped and present no shielding problem in nuclear physics or engineering, although they do present a health hazard if an alpha-emitting isotope is ingested (摄入) in the body. 能量为5MeV的a粒子在空气和铝中的穿透距离大约分别为3.5cm和0.0025cm，从中可以明显看出，尽管它们在被摄入体内后确实对健康有危害，a粒子在核物理或工程上可以非常容易地被阻止，不会造成屏蔽问题。
(5) The word “material” will refer to bulk matter, whether of mineral or biological origin, as well as the particles of which the matter is composed, including molecules, atoms, electrons, and nuclei. “材料”一词是指矿物和生物性质的块状物质，以及组成物质的粒子，其中包括分子、原子、电子和原子核。
3.3. 现在分词做状语
(1) The electron gains energy and moves away with high speed v and total mass-energy mc2, leaving the atom ionized. 电子获得能量并带着总质能mc2高速离开原子核，从而使原子电离。
(2) If its energy is larger, it may impart energy to atomic electrons as
described by the Bohr theory,causing excitation of electrons to higher energy states or producing ionization, with subsequent emission of light. 如果其能量更大，它可以按照波尔理论把能量传递给原子的电子，使电子激发到高能态或电离，并伴随发光现象。
(3) An incident photon of high enough energy dislodges (移出) an
electron from the atom, leaving a positively charged ion. 能量足够高的一个入射光子从原子中击出一个电子，剩下一个带正电的离子。
(4) Electrons also flow in a television tube, where they are made to hit the screen, causing a flash of light. 电子也能在电视显像管中流动，显像管中的电子冲击荧光屏，因而引起闪光。
3.4. 表示“导致”的常用词：
(1) Result in, result from, as a result of
q The above two processes are usually treated separately even though both result in ionization. 尽管都导致电离，上述两个过程通常被分别对待。 q We include those produced by both atomic and nuclear processes and
those resulting from electrical acceleration.我们包括那些由原子和核反应过程中产生的射线，也包括那些由电加速产生的射线。
q The latter process may result in the neutron being captured in the nucleus, being effectively scattered, or causing the fission or splitting of the nucleus. 后一个过程可能导致中子被原子核俘获、被散射、或者原子核的裂变或分裂。
(2) Lead to
q however it is possible that the distortion may lead to a dumbbell shape at which point the Coulomb force of repulsion between the two halves of the dumbbell exceed the nuclear force which is weakened by the distortion of the nucleus. 大多数情况下，扭曲会被核力所限制，在退出激发态后，原子核的球形被恢复，但是，当扭曲可能导致原子核变成哑铃状，这时哑铃的两个半球之间的库仑斥力超过因原子核变形而减弱的核力。 (3) cause, cause by
They cause intense (强烈的) ionization due to their double positive charge, and so lose energy rapidly.它们导致强烈的电离，因为它们具有两个正电荷，并迅速失去能量。
In this isotope fission can be caused by neutrons of any energy, low energy neutrons being the most effective. 对该同位素，裂变可以由任何能量的中子引发，低能量中子最有效。
(4) Produce
Fallout from nuclear weapons testing produces a similar hazard.从核武器试验中放出的辐射微尘会产生相似的危害。
We now turn to a group of three related processes involving gamma ray
photons produced by nuclear reactions. 我们现在开始介绍一下关于由核反应产生的伽马射线光子的三个相关过程。
(5) bring
Control rods, inserted through the removable head, provide sufficient control to bring the core to a hot shutdown condition.从可移动的封头插入的控制棒提供了足够的控制作用以使堆芯达到热停堆条件。
3.5. 表示“原因”的常用词： (1) as a result of
a) However, as a result of nuclear reactions (which might be caused by the bombardment of atoms by protons, neutrons or other light particles), nuclei can be produced in an excited or unstable condition in which one or a number of nucleons are raised to an excited state. 然而，由于核反应的结果，原子核可以产生激态或者不稳定态，其中一个或多个核子被提高到受激态
b) During operation in reactor UO2 pellets suffer structural changes,
principally as a result of the high operating temperatures and high temperature gradients, but also as a result of prolonged irradiation. 运行过程中，二氧化铀芯块需要承受结构变化，主要是由于高的运行温度和高温度梯度造成的，同时也是长期受到辐照的结果。
(2) due to
q Pure plutonium metal is not suitable as reactor fuel due to the large number of crystalline phases which exist up to its melting point of 640oC. 纯钚金属由于其在熔点640oC以下有多种晶相，不适合于作反应堆燃料。
q It is superior to uranium due to its better stability, but it is not used as a fuel in its pure form. 由于其更好的稳定性，钍优于铀，但是它的纯金属态没有被用作燃料。
q The dimensional changes are due to the anisotropic crystalline structure of graphite, and theydepend on its temperature during irradiation. 尺寸变化是由于石墨的各向异性晶体结构所致，尺寸变化取决于辐照的温度。
(3) because of
n Liquid metals are potentially (潜在的) excellent reactor coolants because of their good thermodynamic properties, in particular their high thermal conductivity which leads to very good heat transfer coefficients. 由于其良好的热
动力学性能，尤其是其高热导率可以获得高热传导系数，液态金属是潜在的性能优异的反应堆冷却剂。
3.6. As做状语
n Pure plutonium metal is not suitable as reactor fuel due to the large number of crystalline phases which exist up to its melting point of 640oC. 纯钚由于其在熔点640oC以下有多种晶相，不适合于作反应堆燃料。
n As a reactor fuel plutonium is used as the oxide PuO2. 作为反应堆燃料，钚是以PuO2氧化物的形式使用的。
3.7. 长句子翻译
(1) Studies of the effects of accidents involving the release of radioactive show that, with the exception of those very close to the scene of the accident at the time it happens, the main hazard to the population as a whole arises from the inhalation or ingestion of air or food which is contaminated by the radioactive material from the accident. 对涉及到放射性物质泄漏的事故研究表面，除了那些事故发生时距离现场比较近的人之外，总体上说，事故对人的主要危害来自于吸入或摄入被事故所放出的放射性物质污染的空气或食物。
(2) From the earliest years of nuclear reactor development it has been realized that an accident in which a reactor becomes supercritical by a
substantial amount, resulting in a sudden rise in the fission rate, power and temperature, is an event that can have very serious consequences.
(3) During operation in reactor UO2 pellets suffer structural changes,
principally as a result of the high operating temperatures and high temperature gradients, but also as a result of prolonged irradiation.
(4) The containment consists of a large building, usually about 42 m in diameter (but occasionally up to 64 m) and about 60 m in height built as a pressure vessel and capable of withstanding an internal pressure as high as 0.44MPa
(5) Roughly, twice the amount of heat that has been converted in the turbine for the production of electric power is removed in the condenser for further rejection to the environment due to the second law of thermodynamics which limits the fraction of useful energy that can be attained by a thermal engine. (p.236)
(6) In order to provide additional margin to the containment recirculation screens of AP1000 design, metal reflective insulation is used on lines that are subject to jet impingement during loss-of-coolant accidents and that are not shielded from blowdown jets. As a result, fibrous debris is not generated by loss-of-coolant accidents. Insulation located in a spherical region within a
distance equal to 20 inside diameters of the LOCA pipe break is assumed to be affected by the LOCA when there are intervening components, supports, structures, or other objects. In the absence of intervening components,
supports, structures, or other objects, insulation in a cylindrical area extending out a distance equal to 45 inside diameters from the break along an axis that is a continuation of the pipe axis and up to 5 inside diameters in the radial direction from the axis is assumed to be affected by the LOCA.