is helium 3 truly the clean power they claim it to be ?

Question

helium 3 is not found naturally on the earth but is on the moon, i wonder if this will make it costly.

Answer 1

Sure it would be costly at first, but costs would eventually go down as technology advanced and more people were working to get it. Actually, a group of researchers at the University of Wisconsin (I think - could be wrong) have been doing research on helium-3 fusion and have made quite a bit of progress. Also, there have been other fairly successful fusion trials (the TOCAMAC reactor I believe), the only problem is that the energy output from the fusion reactor is not great enough to surpass the energy needed to run the generator and create a containment field - so at the time, you're actually losing energy when you use the fusion reactor.

The thing about helium-3 is that it is considered extremely clean. Most other fusion reactions use ditritium and uranium (I think those are the two reactants - again you may want to double check me). The fusion reaction between these two reactants yields a lot of energy, but also a lot of harmful radiation. This is why it takes so much power to run the genearators - you have to contain that radiation. Helium-3 on the other hand is, like I said, much cleaner. It yields much less energy but almost no radiation. (Actually, in case your wondering, the clean helium-3 reaction I'm refering to involves the fusing together of 2 helium-3 atoms, not helium-3 and some other element).

And as far as there being helium-3 deep within the Earth, I'm not sure how accurate that is. As you know, helium-3 is an isotope of helium. The thing is, the reason its on the moon is because it is actually a byproduct of the hydrogen fusion reactions occuring in the Sun. Solar wind carries the helium-3 atoms away from the Sun and over billions of years they have become inbeaded in the first few feet of the Moon's soil. And the reason there is 'some' helium-3 on Earth is because it is a byproduct of nuclear weapons. In essence, helium-3 is the byproduct of a lot of radiation producing reactions. Actually, this is why you will find most of the Moon's helium-3 on the far side of the Moon. It is the side most exposed to the Sun's solar winds, while the side facing us is often times (althogh not always) protected by the Earth itself.

Okay, well enough rambling. Hope this helps.

Answer 2

Of course it will be costly. It will have to literally be worth its weight in gold to be cost effective to bring it back from the moon.

Since no one has built a practical fusion reactor, Helium-3 is, for now, completely useless and therefore worthless.

Answer 3

Helium-3 (He-3) is an isotope of Helium with two protons and one neutron, which is rare on Earth; it is sought after for use in nuclear fusion research. More abundant helium-3 is thought to exist on the Moon (embedded in the upper layer of regolith by the solar wind over billions of years) and the solar system's gas giants (left over from the original solar nebula), although still in low quantities (28 ppm of lunar regolith is helium-4 and 0.01 ppm is helium-3 from measurements made on moon rocks brought back by NASA's lunar exploration programs). It is proposed to be used as a second-generation fusion power source.

Some fusion processes produce highly energetic neutrons which render reactor components radioactive with their bombardment, and power generation must occur through thermal means. However, the appeal of helium-3 fusion stems from the nature of its reaction products. Helium-3 itself is non-radioactive. The lone high-energy proton produced can be contained using electric and magnetic fields, which results in direct electricity generation.

However, since both reactants need to be mixed together to fuse, side reactions (21H + 21H and 32He+ 32He) will occur, the first of which is not aneutronic. Therefore in practice this reaction is unlikely to ever be completely 'clean', thus negating some of its attraction. Also, the temperatures required for 21H + 32He fusion are much higher than those of conventional 2H + 31H (deuterium + tritium) fusion.

The amounts of Helium-3 needed as a replacement for conventional fuels should not be underestimated. The total amount of energy produced in the 3He + 21H+ reaction is 18.4 MeV, which corresponds to some 493 megawatt-hours (4.93e8 Wh) per three grams (one mole) of 3He. Even if that total amount of energy could be converted to electrical power with 100% efficiency (a practical impossibility), it would correspond to about 30 minutes of output of a thousand-megawatt electrical plant; a year's production by the same plant would require some 17.5 kilograms of Helium-3. Currently, the practical conversion efficiency between the fuel source and the customer's wall-socket is about 30%, so the actual amounts of Helium-3 would be two or three times higher than the above estimates.

The amount of fuel needed for large-scale applications can also be put in terms of total consumption: According to the US Energy Information Administration, "Electricity consumption by 107 million U.S. households in 2001 totaled 1,140 billion kWh" (1.114e15 Wh). Again assuming 100% conversion efficiency, 6.7 tonnes of Helium-3 would be required just for that segment of one country's energy demand, 15 to 20 tonnes given a more realistic end-to-end conversion efficiency.

Hope this answers your question.

Answer 4

Well, there's about 1,000,000 tons of it in the earth's mantle. It will be usefull in about 40 or 50 years when we get fusion working.