好英语网为什么俄罗斯突然开始谈论“脏弹”？这里是你需要知道的
Western officials quickly rejected Russia’s claim over the weekend that Ukraine was planning to use a so-called dirty bomb in its own territory. The United States and its allies have issued a series of statements accusing leaders in Moscow of making “transparently false allegations” to create a pretext for escalating the war.
上周末，俄罗斯称乌克兰计划在自己的领土上使用所谓的脏弹，西方官员迅速驳斥了这一说法。美国及其盟友发表了一系列声明，指责莫斯科领导人做出“明显虚假的指控”，为升级战争创造借口。
But the intense exchanges in recent days have renewed attention on the concept of the dirty bomb itself.
但最近几天的激烈交锋，重新引发了人们对脏弹这个概念的关注。
10月，乌克兰军人在基辅训练。俄罗斯指责乌克兰准备使用脏弹。
It is a type of weapon that was thought of and tested more than three-quarters of a century ago, in the early years of the atomic age, but never fielded by a military force.
这是一种四分之三世纪前，也就是原子时代早期就设想和试验过的武器，但从未被军事力量投入实战。
In the wake of the Sept. 11 attacks, government officials occasionally warned that terrorists could build one with radioactive materials used in many commercial industries, and dirty bombs became a boogeyman in the public consciousness, an object of fear.
在“9·11”袭击事件后，政府官员偶尔警告说恐怖分子可能会利用许多商业行业都在使用的放射性材料制造一个脏弹，脏弹在公众意识中成为了一种妖魔鬼怪，是令人恐惧的对象。
The more formal name of the bombs — radiological dispersal devices, or R.D.D. — offers a fairly straightforward description of what these weapons are and how they work.
这种炸弹更正式的名称——放射性扩散装置(RDD)——相当直接地描述了这种武器的性质和功能。
Essentially, they are improvised bombs that use conventional high explosives to spread radioactive material into the surrounding area. But the fact that no military is known to have fielded one in its arsenal is a good indicator that they are not useful on the battlefield.
从本质上说，它们是使用常规高强度炸药将放射性物质扩散到周围地区的简易炸弹。但是，没有任何军队在其军火库中部署过这种武器，这一事实很好地表明它们在战场上毫无用处。
What are these weapons?
这种武器是什么样子？
The most commonly imagined version is small enough to fit in a backpack and contains perhaps 20 pounds or less of explosives, with a smaller mass of radioactive material placed on top.
最常见的设想版本是小到可以装进背包里，可能含有20磅（约合九公斤）或更少的炸药，顶端放有少量放射性物质。
That’s about the extent of it, though such a weapon potentially could be made much larger.
这就是它的大小，尽管这样的武器可能会被做得更大。
There are, however, some inherent issues with this concept that limit a bomb maker’s chances of success. First, the size of the main charge: Use too much explosive material and the radioactive substance could be largely consumed by the intense heat as the bomb detonates. Use too little and the device would not spread the radioactive material very far.
然而，这一概念存在一些固有的问题，限制了炸弹制造者成功的机会。首先是主要填充物的尺寸：如果使用过多的爆炸材料，放射性物质就会在炸弹爆炸时被强烈的热量消耗掉。如果爆炸材料太少，装置就无法把放射性物质扩散得很远。
Another consideration is that only a few radioisotopes, which are commonly used for medical purposes or power generation, are suitable for use in this kind of device.
另一项考虑是，只有少数通常用于医疗目的或发电的放射性同位素适合用于这种装置。
A radiological dispersal device is not a “nuclear weapon” in the classical sense, as there is no fission, no fusion, no massive release of energy nor city-cratering destruction.
放射性扩散装置不是传统意义上的“核武器”，因为它没有裂变，没有聚变，没有大规模的能量释放，也没有毁灭城市的能力。
What happens if one explodes?
如果一个脏弹爆炸，会发生什么？
If everything works correctly — and as an improvised bomb there are many potential failure points — a dirty bomb blasts radioactive material into tiny bits and sends it into the surrounding air. It produces a localized contamination problem, not a global one.
如果一切正常——作为一种简易炸弹，它会有许多可能出现故障的地方——脏弹会将放射性物质炸成微小的碎片，并将其释放到周围的空气中。它产生的污染问题是局部的，而不是全球性的。
People who inhale or ingest radioactive dust could be injured or killed, and contaminated buildings would have to be bulldozed and sent to a landfill. Excavators would likely dig up radiated soil a yard deep and tear down nearby trees — all of which would be sent to landfills as well.
吸入或摄入放射性尘埃的人可能会受伤或死亡，受污染的建筑物必须被推土机铲平，送往垃圾填埋场。挖掘机可能会挖出一码深（约合91厘米）的辐射土壤，并推倒附近的树木——所有这一切也将被送往垃圾填埋场。
But a lot of the effects would depend on atmospheric conditions.
但很多影响取决于大气条件。
Temperature gradients would affect how high the plume of radioactive material could rise up into the air, and the speed and direction of the wind would determine how far it could spread from the blast.
温度梯度将影响放射性物质羽流上升到空气中的高度，而风速和风向将决定它能从爆炸中扩散到多远。
An academic paper published in a U.S. military magazine on the topic in 2004 noted that “economic and psychosocial effects are likely to be the most serious damage mechanisms from any use of an R.D.D.”
2004年在美国军事杂志上发表的一篇关于该主题的学术论文指出，“经济和心理效应可能是任何使用RDD最严重的破坏机制。”
“The fear of ionizing radiation is a deep-seated and frequently irrational carry-over from the Cold War,” the report said. And while an attack with this kind of device “is unlikely to cause mass deaths,” it has the potential to “cause great panic and enormous economic losses.”
该论文说：“对电离辐射的恐惧是冷战遗留下来的问题，它根深蒂固，往往是非理性的。”虽然使用这种装置的袭击“不太可能造成大规模死亡”，但它有可能“造成巨大的恐慌和巨大的经济损失”。
Are there other risks?
还有其他风险吗？
There is significant risk to the bomb maker while building this kind of weapon.
在制造这种武器的过程中，炸弹制造者面临着巨大的风险。
For the weapon’s radiation to be lethal, the radioisotope used would have to have a strong enough intensity to harm people.
要使武器的辐射达到致命程度，所使用的放射性同位素的强度必须足够大，才能对人造成伤害。
If the bomb makers acquire radiological material that is in a shielded container — meaning a vessel built in such a way to keep harmful rays from being emitted — they would have to make a critical decision: whether or not to attempt removal of the radioactive material.
如果炸弹制造者获得的放射性材料被放在屏蔽容器——指的是防止有害射线发射的特制容器——他们将不得不做出一个关键的决定：是否尝试移出放射性材料。
The bomb makers may think removing the shielding will allow for better dispersal of the radioactive material. But doing so can expose them to harmful ionizing radiation at very close range for long enough to do real damage to their bodies — a fundamental hazard of working around radioactive materials.
炸弹制造者可能认为，拆除屏蔽层可以令放射性物质更好地扩散。但是这样做会使他们在很近的距离内长时间暴露在有害的电离辐射中，从而对他们的身体造成真正的伤害——这是在放射性材料周围工作的基本危害。
Then there is the possibility of the attacker being discovered en route to place the bomb, with a strong radioactive source potentially tripping detectors along highways and bridges that alert law enforcement.
此外，袭击者也有可能在放置炸弹的途中被发现，强辐射源可能会触发高速公路和桥梁上的探测器，从而向执法部门发出警告。
Has the U.S. military ever built a weapon like this?
美国军方制造过这样的武器吗？
According to government documents, the U.S. military experimented with radiological dispersal devices at Dugway Proving Ground in Utah from 1948 to 1952, but that work was ultimately abandoned.
政府文件显示，1948年至1952年，美国军方曾在犹他州的杜格威试验场测试过放射性扩散装置，但这项工作最终被放弃。
Aside from these tests, in which radiological dispersal devices of various kinds were built, there is no evidence that the U.S. military or another force ever fielded such a weapon for use in combat.
除了这些制造了各种辐射扩散装置的试验之外，没有证据表明美军或其他部队曾在战斗中部署过这种武器。