Bilingual edition: English is preserved and Chinese follows each unit. Terminology uses the confirmed v20260916 glossary; automated semantic review remains traceable.
中英双语版：英文原文完整保留，中文紧随对应单元；术语采用 v20260916 确认表，自动语义审校结果可追溯。
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Three Mile Island concepts

Nuclear energy concepts

Fission concepts
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Misleading behavior of a safety valve quickly compounds the problem.

安全阀的误导性行为迅速加剧了问题。

1. Secondary loop boils down to a low level, superheating the primary loop.

二次回路最终归结为一个低电平，使一次回路超温。

2. Pressure rises above 2350 psi, opening safety valve to quench tank. Radioactive steam and water move to quench tank.

压力超过2350 psi时，安全阀打开，将放射性蒸汽和水引入淬火罐。

3. Valve tries to close when pressure drops below 2300 psi, but doesn't seat. However, it closes enough to trip the indicator in the control room, so operators think it is closed.

当压力下降到2300 psi以下时，阀门试图关闭，但未能完全密封。然而，它关闭了足够多的行程以触发控制室的指示器，因此操作人员认为它已经关闭了。
Index

Three Mile Island concepts

Nuclear energy concepts

Fission concepts
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The stuck relief valve leads to some radiation release

安全泄放阀导致一些辐射释放
Iodine-131
碘-131
What is a mrem?
什么是毫雷姆？
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Meanwhile, back at the reactor ...

Meanwhile, back at the reactor ...（专名或术语）

- With the cooling effect of the restored feedwater and the stuck relief valve, the reactor pressure drops quickly.

在恢复的给水冷却作用以及堵塞的泄压阀作用下，反应堆压力迅速下降。

- At 1600 psi the Emergency Core Cooling System kicks in automatically, flooding the core with high pressure water.

在1600 psi时，应急冷却系统会自动启动，向反应堆核心注入高压水。

- Even though the reactor has "scrammed" and the control rods have stopped the fission chain reaction, the residual reactions still produce 5-7% of full heating power. For an 800 MW electrical, 2400 MW thermal reactor, this amounts to 120-170 Megawatts of heating power.

即使反应堆已“ scrammed ”，控制棒已停止裂变链式反应，残留的反应仍产生全功率加热功率的5-7%。对于一个800兆瓦电功率、2400兆瓦热功率的反应堆，这相当于120-170兆瓦的加热功率。
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Three Mile Island: A Brief Chronology

三哩岛：简要时间线
由于除盐器中阀门未正确关闭，凝结水泵停机
Time
时间
 Event
事件
0Condensate pump shuts down due to improperly closed valve in demineralizer.
2 sec
2秒
Turbine automatically switches off. Pressure rises to 2255 psi, opens relief valve. It fails to close.
涡轮机自动关闭。压力升至2255 psi，开启安全阀。它未能关闭。
8 sec
8 秒
Sensing high pressure, reactor "scrams", dropping all control rods.
感知到高压，反应堆‘ scram ’，全部拔出控制棒。
9 sec
9 秒
Fission reaction stops. (Fission products still produce heat.)
裂变反应停止。（裂变产物仍会产生热量。）
14 sOperator notes that emergency feedwater pumps are on.
操作员指出应急给水泵已启动。
1:45Steam generator (secondary loop) boils dry.
蒸汽发生器（二次循环）开始干烧。
2 min
2 分钟
Emergency core cooling system (ECCS) automatically turns on when pressure drops below 1600 psi.
紧急冷却系统（ECCS）在压力降至1600 psi以下时会自动启动。
2.5 min
2分30秒
Operators shut down the ECCS!!
操作员关闭了ECCS！！
By this time the operators were dealing with about 100 alarms!!
到那时，操作员们正在处理大约100个警报！
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The ECCS was shut off!!

ECCS被关闭了！！

- The operators were afraid that the water level would get too high, that the reactor would "go solid". If the water filled the reactor, it would act like a hydraulic press and force the reactor lid off.

操作员担心水位会过高，使反应堆“固态化”。如果水填满反应堆，它会像液压机一样将反应堆盖板顶开。

- After over an hour of heating, the coolant pumps were shut off, worsening the already bad situation.

在加热超过一小时后，冷却泵被关闭，使本已糟糕的情况更加恶化。

- Two-thirds or more of the 12 foot core was uncovered. At 150 MW of heating it would take only 30 seconds for fuel melting to start if all cooling was lost.

- A large hydrogen "bubble" was formed at the top of the reactor by reaction between the zirconium fuel rod cladding and the superheated water.

反应在超热水中，锆燃料棒包壳与氢气反应形成了一个巨大的氢气‘气泡’，位于反应堆顶部。
The core was recovered with water after about 6.5 hours of exposure!!

12英尺核心的三分之二或更多部分被暴露出来。如果所有冷却系统都失效，当功率达到150兆瓦时，燃料熔化将仅需30秒开始。核心在暴露约6.5小时后被水回收!!

Though now largely forgotten, there were national headlines for about a week concerning the large hydrogen bubble that had formed at the top of the reactor vessel. In retrospect, since the bubble formed by the interaction with the hot zircalloy tubes and the steam there was no significant risk of the hydrogen exploding in the reactor vessel itself because there was no available oxygen. The formation of the hydrogen bubble occured because the superheated zircalloy stripped oxygen away from the steam, creating the hydrogen bubble. With the zircalloy that hungry for oxygen, there wasn't going to be enough available to explode the hydrogen bubble.

尽管现在已 largely 被遗忘，但当时有大约一周的时间，有关反应堆压力容器顶部形成一个巨大的氢气泡的新闻占据了全国头条。回顾来看，由于氢气泡是通过与高温锆合金管和蒸汽的相互作用形成的，因此在反应堆压力容器内氢气爆炸并无显著风险，因为当时没有可供爆炸的氧气。氢气泡的形成是因为超高温的锆合金剥离了蒸汽中的氧气，从而形成了氢气泡。由于锆合金对氧气有强烈的渴望，因此可供爆炸的氢气泡量将不足以引发爆炸。
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Three Mile Island Reactor Damage

三哩岛反应堆损坏

The financial cost of the Three Mile Island nuclear accident was on the order of a billion dollars. The entire fuel assembly in the reactor was damaged by the heat and the reaction of the hot steam with the zircalloy tubing which contained the fuel pellets.

三里岛核事故的财务成本约为十亿美元。反应堆中的整个燃料组件因热量和热蒸汽与包覆燃料 pellet 的锆合金管的反应而受损。
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