How close are we to powering the world with nuclear fusion? - George Zaidan

翻译人员: Lexi Ding 校对人员: Shuhui Huang

In the time it takes to snap your fingers,

在你打个响指的时间里，

the Sun releases enough energy to power our entire civilization for 4,500 years.

太阳释放的能量就足够 我们整个文明使用 4500 年。

So naturally, scientists and engineers have been working to build

因此，科学家和工程师 自然而然地致力于在地球上

a miniature star here on Earth... to plug into our power grid.

建造一颗微型恒星…… 接入我们的电网。

And the thing is, we already kind of have.

但问题是，我们已经有了。

It just doesn’t look like a tiny star floating in a lab.

它只是看起来不像一颗 漂浮在实验室中的小恒星。

The stars are made of an almost incomprehensible number of particles,

恒星是由数量多得 几乎难以理解的粒子组成的，

which gravity compresses into a super dense core.

这些粒子在重力作用下 被压缩成一个超级致密的核。

This core is hot and dense enough to force atomic nuclei together,

这个核的温度和密度 足以迫使原子核结合在一起，

forming larger, heavier nuclei in a process known as fusion.

在一个被称为聚变的过程中 形成更大、更重的原子核。

The reverse process, where one atom splits into two, is called fission.

与之相反的过程，即一个原子 分裂成两个，称为裂变。

In both processes, the mass of the end products is slightly less

在这两个过程中，最终产物的质量

than the mass of the initial atoms.

都略小于初始原子的质量。

But that lost mass doesn’t disappear—

但是损失的质量并没有消失——

it’s converted to energy according to Einstein’s famous equation.

根据爱因斯坦的著名方程式， 它会转化为能量。

And since c² is such a massive number,

而且，由于 c² 是一个 如此庞大的数字，

both fission and fusion generate a lot of energy.

裂变和聚变都会产生大量的能量。

Fusion in our Sun mostly produces helium nuclei.

太阳中的聚变主要产生氦核。

In the most common pathway, two protons fuse to form a deuterium nucleus,

在最常见的途径中， 两个质子融合形成一个氘核，

which then fuses with another proton to form a helium-3 nucleus,

然后与另一个质子 融合形成一个氦-3 核，

which then fuses with another helium-3 nucleus to form a helium-4 nucleus.

再与另一个氦-3 核 融合形成一个氦-4 核。

But there’s a catch— that first step is incredibly rare.

但是有一个问题—— 第一步非常难实现。

Only 1 in 100 septillion collisions between protons

质子间的碰撞 每 100*10的 24 次方的次数

results in a deuterium nucleus.

才有 1 次产生氘核。

In the Sun this isn’t a problem because there are so many protons

在太阳中，这不是问题， 因为质子数量太多。

that even a reaction this rare happens all the time.

即使是如此罕见的反应 也会一直发生。

But on Earth, researchers rely on a more easily reproducible reaction,

但在地球上，研究人员依靠的 是一种更容易复制的反应，

where a deuterium nucleus fuses with a tritium nucleus

即氘核与氚核融合，

to form a helium-4 nucleus and a neutron.

形成氦-4 核和一个中子。

We’ve actually been doing reactions like this one inside particle accelerators

实际上，自 20 世纪 30 年代以来， 我们就一直在粒子加速器内

since the 1930s.

进行类似的反应。

But these accelerators are not designed to harness the energy this reaction releases.

但是这些加速器并不是为了利用 这种反应所释放的能量而设计的。

Rather, they’re used to generate neutrons

相反，它们是用来产生中子的，

for a variety of scientific and military purposes.

用于各种科学和军事目的。

Whereas if we want to use fusion to produce limitless energy,

而如果我们想利用核聚变 产生无限的能量，

we’d need a device that can harness the energy released,

我们就需要一个能收集 释放出的能量的装置，

channel enough of that energy back into the device to keep the reaction going,

将足够维持反应进行的能量 导回装置内部，

and then send the rest out to our power grid.

然后将剩余的能量 输送到我们的电网。

And for that job, we need a nuclear fusion reactor.

为此，我们需要一个核聚变反应堆。

Like a particle accelerator, a reactor would generate helium nuclei and neutrons.

像粒子加速器一样， 反应堆会产生氦核和中子。

But that reaction would happen in a superhot core

但这种反应会发生在 一个超热的核中，

and the resulting neutrons would shoot outward

由此产生的中子会向外射击，

to heat up a layer of lithium metal.

加热一层锂金属。

That heat would then boil water,

然后，这些热量将使水沸腾，

generating steam to run turbines and produce electricity.

产生蒸汽，驱动涡轮机发电。

Meanwhile, the helium nuclei would stay in the core

与此同时，氦核将留在核中

and slam into other nuclei to keep the reaction going—

并撞击其他原子核， 以保持反应的进行

and the electricity flowing.

和电流的流动。

This tech has many practical challenges,

这项技术面临许多实际挑战，

including how to confine a swirling mass of million-degree matter.

包括如何限制 不停旋转的上百万度的滚烫物质。

But the biggest hurdle is achieving what's called ignition.

但最大的障碍是实现所谓的点火。

An energy technology is only commercially viable

一种能源技术只有当其输出的能量 大于其使用的能量时，

if it puts out more energy than it uses.

才具有商业可行性。

And a fusion reactor needs a lot of energy to get the core hot enough

而核聚变反应堆需要大量能量 才能使堆芯温度足够高，

for fusion to occur.

从而发生核聚变。

So there’s a tipping point:

因此存在一个临界点：

a moment when the fuel is hot enough to start the reaction

当燃料的温度足以启动反应，

and release more energy than is needed to reach and maintain that temperature.

并释放出超过达到并维持 该温度所需的能量时。

This is ignition.

这就是点火。

Stars reach ignition under the force of huge amounts of gravity,

恒星在巨大引力的作用下 达到点火状态，

but this approach is impossible on Earth

但这种方法在地球上是不可能的，

since you’d need thousands of times the mass of, well, the entire Earth.

因为你需要数千倍于 整个地球的质量。

So researchers typically rely on vast arrays of lasers,

因此，研究人员通常依靠 巨大的激光阵列，

or methods that combine magnets with high energy particles

或者将磁铁与高能粒子 或电磁波结合的方法，

or electromagnetic waves similar to those in your microwave oven.

和你家中微波炉的电磁波很类似。

In 2022, scientists at the US National Ignition Facility

2022 年，美国国家点火设施 (US National Ignition Facility) 的科学家们

demonstrated ignition for the first time ever,

首次演示了点火，

using 192 lasers to heat deuterium and tritium to 100 million degrees.

他们使用 192 台激光器 将氘和氚加热到了 1 亿度。

While this was a huge step forward,

虽然这是向前迈出的一大步，

we’re still a ways off from a self-sustaining, long-running reactor

但我们距离一个 能够自我维持、长期运行、

that produces more energy than it uses.

产生大于使用能量的反应堆 仍有一段距离。

But once operational, these relatively small reactors could power a city

但一旦投入运行，这些相对较小的 反应堆只需两辆小卡车的燃料，

of a million people for a year with just two pickup trucks of fuel.

就能为一个拥有一百万人口的城市 提供一年的电力。

Today, you’d have to burn roughly 3 million tons of coal

如今则必须燃烧 大约 300 万吨煤

to produce that much energy.

才能产生这么多的能量。

That is the promise of fusion:

这就是核聚变的前景：

limitless, on-demand energy with almost no emissions.

无限的按需能源， 几乎没有排放。

True star power, right here on Earth.

真正的星之力，就在地球上。