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Nuclei

Helium-3

He3-He3 Reaction There are three main energy producing processes in the interior of the Sun. One of them is the proton-proton reaction as shown below:

Figure 14-17 He3-He3 Reaction [view large image]

 The He3-He3 reaction (Figure 14-17) in the third step is by far the most frequent of the various alternatives under a central temperature of about 15x106 K.

He3-D Reaction Another possibility for He3 fusion is via the reaction with D2 (Figure 14-18):

He3 + D2 H1 + He4 + 18.4 Mev

The fusion reaction rate becomes significant at a temperature of about 10x106 K, and peak about 200x106 K. Researchers see He3 as the perfect fuel source: extremely potent, nonpolluting, with virtually no radioactive by-product. The trouble is, hardly any of it is found on Earth. But there is plenty of it on the Moon.

Figure 14-18 He3-D Reaction [view large image]
Since He-3 is produced in the second step of the proton-proton reaction, this element is dispersed in the Solar system by the solar wind. Little of this product reaches Earth before deflected away by the Earth's magnetic field. But the Moon's magnetic field is less than one-millionth that of the Earth, thus lot of He-3 is deposited in the powdery soil on the Moon's surface.

Fusion research began in 1951 in the United States under military auspices. After its declassification in 1957scientists began looking for a candidate fuel source that wouldn't produce neutrons. Although helium-3 was discovered in 1939, only a few hundred kilograms were known to exist on Earth, mostly the by-product of nuclear-weapon production. For solving long-term energy needs, proponents contend helium-3 is a better choice than first generation nuclear fuels like deuterium and tritium, which are now being tested on a large scale worldwide in Tokamak thermonuclear reactors. That's because reactors that exploit the fusion of deuterium and tritium release 80 percent of their energy in the form of radioactive neutrons, which exponentially increase production and safety costs. In contrast, helium-3 fusion would produce little residual radioactivity. A nuclear reactor based on the fusion of helium-3 and deuterium would produce very few neutrons -- about 1 percent of the number generated by the deuterium-tritium reaction.

IEC Recent reports indicate progress toward making helium-3 fusion. Inside a lab chamber, researchers have produced protons from a steady-state deuterium-helium3 plasma at a rate of 2.6 million reactions per second. That's fast enough to generate fusion power but not churn out electricity. The chamber, which is roughly the size of a basketball, relies on the electrostatic focusing of ions into a dense core by using a spherical grid called Inertial Electrostatic Confinement

Figure 14-19 IEC
[view large image]

 (IEC) fusion system. Figure 14-19 shows a schematic diagram and the actual construction of an IEC. This one is used for neutron generation.

Moon Base Meanwhile, news in November 2005 reports that China will make a manned moon landing around 2017. The project includes setting up a moon-based astronomical telescope, measuring the thickness of the moon's soil and the amount of helium-3 on the moon. According to the Chinese announcement: "It will provide the most reliable report on helium-3 to mankind". The United States has unveiled a $104 billion plan in September, 2005 to return Americans to the moon by 2018. Figure 14-20 shows the renderings of a Moon Base by NASA-commissioned artists.

Figure 14-20 Moon Base
[view large image]

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