Artemis数据预订
2.9 Fusion Power from the Moon
Lunar Helium-3 as an Energy Source, in a nutshell
The Setting
For the purposes of this discussion, let’s assume that the helium-3 fusion plants have been proved out, and folks are frantically building them, just waiting for us to show up with with tanks full of He³.
The Ingredients of Nuclear Fusion
The names of the ingredients for nuclear fusion reactions — deuterium, tritium, isotopes of helium, sound complicated, but really these are only variations on substances found in everyday life. We’ll assume you understand that atoms are made up of protons, neutrons, and electrons.Electons是非常轻量级的,带负电荷的位that buzz around the edges of an atom. Regular chemical reactions work by trading and sharing electons among atoms. For instance, when you burn a piece of paper in air, the chemical reaction involves some carbon atoms in the paper sharing electrons with some oxygen atoms from the air. The reaction forms carbon dioxide gas while the electons give off energy, as heat and light, when they change their orbits.
质子andneutrons弥补原子的核心。在这次讨论中，我们关注重新安排原子的核心;因此，“核反应”一词。通常，中性带电的中子将带正电荷的质子保持彼此战斗。原子的核心非常紧密地束缚在一起，所以当我们开始移动这些东西时，我们正在以大的方式移动能量。
Hydrogenis the familiar stuff used to make up water by combining it with oxygen. It’s the most abundant element in the universe. Normal hydrogen has 1 proton and no neutrons.氘is an isotope of hydrogen that has a neutron next to its lonely proton.
你熟悉heliumgas as the stuff we use to blow up blimps and balloons. Normal helium has 2 protons and 2 neutrons in its nucleus, giving it an atomic weight of 4.
Now, if you kick out one of neutrons, you get helium-3. This happens once in a while in very energetic nuclear reactors, especially the sun. The sun produces helium by fusing hydrogen atoms together, but about one in every ten thousand helium atoms comes out missing a neutron.
Helium-3 casts lustful eyes upon that neutron in the deuterium, and will grab it if it gets a chance. We give it a chance by introducing the helium-3 to the deuterium at a high temperature.
The Mixture
Helium-3用于与氘的反应中产生能量：
这是一个核聚变反应。氘的nd helium-3 atoms come together to give off a proton and helium-4. The products weigh less than the initial components; the missing mass is converted to energy. 1 kg of helium-3 burned with 0.67 kg of deuterium gives us about 19 megawatt-years of energy output.
The fusion reaction time for the D«»He³ reaction becomes significant at a temperature of about 10 KeV, and peaks about about 200 KeV. A 100 KeV, or so, reactor looks about optimum.
A reactor built to use the D«»He³ reaction would be inherently safe. The worst case failure scenario would not result in any civilian fatalities or significant exposures to radiation.
笔记：MeVand凯夫are measures of energy, standing for mega-electron volts and kilo-electron volts, respectively. In nuclear physics, these terms are used to refer to the amount of energy in a nuclear reactor. One electron volt is the energy acquired by one electron falling through a potential of one volt, equal to approximately 1.609 E-19 joule.
The supply
地球上有一些氦气3。它是维护核武器的副产品，这些核武器将提供约300公斤的氦3，可以继续每年生产约15公斤。美国氦气的总供应量是29公斤，另外187公斤与我们储存的天然气混淆;这些来源不能以任何重大速度可再生。
In their 1988 paper, Kulcinski, et al. (see ref note below), estimate a total of 1,100,000 metric tonnes of helium-3 have been deposited by the solar wind in the lunar regolith. Since the regolith has been stirred up by collisions with meteorites, we’ll probably find helium-3 down to depths of several meters.
The highest concentrations are in the lunar maria; about half the helium-3 is deposited in the 20% of the lunar surface covered by the maria.
To extract helium-3 from the lunar soil, we heat the dust to about 600 degrees C.
我们同时获得大部分其他挥发物，所以我们无论如何我们将升温岩石。要获得Oogenen，我们会把炉子转到大约900°C，做一些其他令人讨厌的东西;但这是一个不同的故事。
The Energy
与氘反应的100万公吨氦3，将产生约20,000个Terrawatty的热能。单独的单位是令人敬畏的：一个Terrawatty一年是一万亿，
10 to 12th power watt-years. To put this into perspective, one 100-watt light bulb will use 100 watt-years of energy in one year.
这是我们可以从地球上的所有化石燃料中挖掘的10倍，而没有烟雾和酸雨。如果我们在液态金属快速饲养反应堆中侵入所有铀，我们可以产生大约一半的能量，并且有一些有趣的时间储存废物。
The Value
About 25 tonnes of helium-3 would power the United States for 1 year at our current rate of energy consumption. To put it in perspective: that’s about the weight of a fully loaded railroad box car, or a maximum Space Shuttle payload.
To assign an economic value, suppose we assume helium-3 would replace the fuels the United States currently buys to generate electricity. We still have all those power generating plants and distribution network, so we can’t use how much we pay for electricity. As a replacement for that fuel, that 25-tonne load of helium-3 would worth on the order of $75 billion today, or $3 billion per tonne.
收益
A guess is the best we can do. Let’s suppose that by the time we’re slinging tanks of helium-3 off the moon, the world-wide demand is 100 tonnes of the stuff a year, and people are happy to pay $3 billion per tonne. That gives us gross revenues of $300 billion a year.
To put that number in perspective: Ignoring the cost of money and taxes and whatnot, that rate of income would launch a moon shot like our reference mission every day for the next 10,000 years. At that point, we will have used up all the helium-3 on the moon and had better start thinking about something else.
Reference: Kulcinksi, Cameron, Santarius, Sviatoslavsky, and Wittenberg, “Fusion Energy from the Moon for the 21st Century.” 1988. Fusion Technology Institute, University of Wisconsin.
有关更多信息：氦-3作为21世纪的能源来源。
