The accident On Saturday April 26, 1986, at 1:23:58 a.m. local time, the unit 4 reactor of the Chernobyl power plant—known as Chernobyl-4—suffered a catastrophic steam explosion that resulted in a fire, a series of additional explosions, and a nuclear meltdown. [edit] 意外 在1986年4月26日的星期天早上当地时间1点25分58秒，车诺比发电厂的第四号反应炉，也 就是为人所知的车诺比四号，发生了灾难性的蒸气爆炸，造成了不可收拾的大火及 一连串的爆炸，也导致了炉心溶毁。 Causes There are two conflicting official theories about the cause of the accident. The first was published in August 1986 and effectively placed the blame solely on the power plant operators. The second theory, proposed by Valeri Legasov and published in 1991, attributed the accident to flaws in the RBMK reactor design, specifically the control rods. Both commissions were heavily lobbied by different groups, including the reactor's designers, Chernobyl power plant personnel, and the government. Some independent experts now believe that neither theory is completely correct. Another important factor contributing to the accident was that the operators were not informed about problems with the reactor. According to one of them, Anatoliy Dyatlov, the designers knew that the reactor was dangerous in some conditions but intentionally concealed this information. Contributing to this was that the plant's management was largely composed of non-RBMK-qualified personnel: the director, V.P. Bryukhanov, had experience and training in a coal-fired power plant. His chief engineer, Nikolai Fomin, also came from a conventional power plant. Anatoliy Dyatlov himself, deputy chief engineer of Reactors 3 and 4, only had "some experience with small nuclear reactors", namely smaller versions of the VVER nuclear reactors that were designed for the Soviet Navy's nuclear submarines. 起因 官方对於这次事件的起因提出了两个互相矛盾的理论。第一个理论在1986年8月被提出并 把所有的矛头指向发电厂的操作员。第二个则是由Valeri Legasov在1991年所提出，此次 报告把这次意外归因於RBMK(石墨沸水管反应器)核子反应炉的设计瑕疵上，特别是在控制 棒的设计上。提出这两个理论的调查委员会都受到来自於反应炉设计者、车诺比发电厂员 工以及政府部门在内的多方施压及游说。而一些独立而不受干预的研究相信这两个理论皆 非完全正确。 另一个促使意外发生的重要因素则是操作员并未被告知反应炉潜在性的问题。依据其中一 名员工Anatoliy Dyatlov的说法，反应炉的设计者知道反应炉在某种情况下可能造成危险 ，但他不但没有将这个问题揭露出来，反而刻意的隐瞒事实。此外，由於发电厂的管理人 员大部分都没有操作过RBMK核子反应炉的经验也是造成悲剧的因素之一，如发电厂的厂长 V.P. Bryukhanov只有过燃煤发电厂的历练，首席工程师Nikolai Fomin来自一个传统动力 发电厂，而第三号及第四号反应炉的副工程师Anatoliy Dyatlov自己则只有过操作一些小 型核反应炉的经验，如前苏联海军的核子动力潜艇所使用的的小型VVER(或是WWER,轻水式 反应器)反应炉。 In particular, 细节 * The reactor had a dangerously large positive void coefficient. The RBMK reactor design used liquid as its coolant. Coolant gives the operators some control over the speed of the reactions, controlling the reactors energy output. If the coolant has bubbles in it (voids), from steam, these voids increase the amount of energy the reactor produces (i.e. no liquid to absorb neutrons). Without intervention, the reactor produces more energy, creating more voids, becoming harder to control. That the RBMK reactor design was dangerous at low power levels was counter-intuitive and unknown to the crew. *反应炉有着一个危险的正空泡系数。RBMK(石墨沸水管反应器)反应炉使用"液体(轻水)" 来当作冷却剂.而冷却剂可以用来帮助操作员控制反应器的反应速率及控制反应器的能量 输出功率。假如冷却剂在反应器内形成蒸气气泡，会使得反应炉内的核反应加剧(也就是 说没有"液体"可以来吸收中子了)。少了这些液体的干预，反应炉产生了更多的能量，变 成了恶性循环，使得越来越多的液体变成蒸气，最终使得反应变得难以控制。RBMK反应炉 在低功率运转时会造成危险，但工作人员并不明白这点且这个概念(即低功率运转会造成 危险)也和他们原本所预期的相反。 * A more significant flaw of the reactor was in the design of the control rods. In a nuclear reactor, control rods are inserted into the reactor to slow down the reaction. 1[;32mHowever, in the RBMK reactor design, the control rod end tips were made of graphite, the extenders (the end areas of the control rods above the end tips, measuring 1 m in length) were hollow and filled with water, while the balance of the control rod—the truly functional area, absorbing the neutrons and thereby halting the reaction—were made of boron carbide. For the initial few moments when control rods of this design are inserted into the reactor, coolant was displaced by the graphite ends of the rods. The coolant (water), a neutron absorber, was therefore replaced by graphite, a neutron moderator – that is, a material that enables the nuclear reaction rather than slow the reaction down. For the first few seconds of control rod activation the rods increased the reactor's speed, rather than the desired effect of decreasing the reaction. This behavior is rather counter-intuitive and was not known to the reactor operators. *反应炉在控制棒的设计上更是有明显的瑕疵。在核子反应炉中，控制棒是被插反应炉当 中以用来减低反应的速率。然而，在RBMK(石墨沸水管反应器)反应炉的设计中，控制棒的 末端是由石墨所制成，延长的区域(指在控制棒末端上方1公尺的范围)是由碳化硼所构成 而其内部为中空且充满着水，这部份用来平衡控制棒且做为吸收中子进而停止连锁反应。 在这种控制棒(RBMK型)被插入反应炉後，做为中子吸收剂的冷却剂(水)在极短时间内就 被在控制棒末端做为中子缓和剂的石墨所取代。也就是说，石墨不能减慢核反应的速率而 是增加核反应的速率(译者注:缓和剂可以减低中子能量使之变为慢中子进而引发下一个铀 -235原子核之分裂)。 而反应炉操作者并不明白这点且这种概念也和他原本的预期相反， 所以在最初的几秒内，控制棒加速了核反应，而不是如期望般的减慢反应。 中间有一小段不大会翻(while...那里)不大会翻且觉得这段前後意思有点矛盾? 前面说这型的控制棒可以吸收中子然後停止反应，可是後文中又说RBMK 用的控制棒无法减缓反应@.@ * The operators were careless and violated plant procedures, partly due to their lack of knowledge of the reactor's design flaws. Also, several procedural irregularities contributed to the cause of the accident. One was insufficient communication between the safety officers and the operators in charge of an experiment being run that night. *操作员太过大意且违背了发电厂的操作程序，而部分的原因则是他们不知道反应炉原本 就存在的瑕疵。此外，许多程序上的错误也导致了这次意外的发生。其中一个即是安全人 员与那天晚上负责试验的操作员在沟通上的不良所造成。 * It is important to note that the operators switched off many of the reactor's safety systems, which was generally prohibited by the plant's published technical guidelines. According to a Government Commission report published in August 1986, operators removed at least 204 control rods from the reactor core (out of a total of 211 for this reactor model), leaving seven. The same guidelines (noted above) prohibit operation of the RBMK-1000 with fewer than 15 rods inside the core zone. *最值得注意的就是操作员们关掉了许多在技术指导手册中被禁止关闭的反应炉安全装置 。依据一份政府委员会在1986年所公布的报告，操作员从反应炉核心抽出204只以上的控 制棒(从RBMK-1000反应炉所拥有的211只中抽出)，只留下了7只。如同上文所提到指导手 册中写着RBMK-1000型不得在少於15只控制棒的情况下运作。 有一些核子工程的名词不知道翻得正不正确 请熟悉核子工程的人在提出来喽 BTW，这种文章是不是应该要移到翻译版询问才对@.@ --

※ 发信站: 批踢踢实业坊(ptt.cc) ◆ From: 220.132.37.151 ※ 编辑: maximum 来自: 220.132.37.151 (04/28 16:44)