In the same light, lemme mention what I consider to be a pretty good science fiction topic…
Another viable fusion combination is Deuterium and Helium-3. This kills the high radiation problem. Helium-3 is very rare on Earth, but is easily available in vast quantities on the Moon.
So, if we get fusion to be viable enough to make it worth the cost of Moon missions, we have a very clean energy source and we have a real practical reason for colonizing the moon. And of course the missions would probably be a lot cheaper if most of them were one-way deliveries from the Moon to the Earth.
Ok so someone want to explain to me why neutron radiation from fusion is so much rosier that neutron radiation from fission?
and while we are at it, how the H3 concetrations could be so much higher on the moon than on earth, when its strongly supported that the moon is a chip off of the earth.
Why would you assume that they are the same? Yes, they are still neutrons, but there is no reason to assume that the emission rates are on the same order of magnitude. A single combination of deuterium and tritium always emits one neutron. Fission generally results in multiple neutrons per split atom. More importantly, why assume that the rate at which atoms are split in a fission reaction are similar to the rate at which atoms are fused in hydrogen fusion?
In addition, the whole layout of fission and fusion are different. A fission reactor needs moving parts in the reactor itself, like control rods, while a fusion reaction is controlled only by magnetic fields. The option of using materials that help prevent long-term radioactivity might simply not be an option for fission. Speaking of control rods, do you know if they are part of the material that becomes waste? I have often wonderered about that. After all, they are specifically designed to be good neutron absorbers. Fusion doesn’t require any such animal.
But since there still will be a radioactive waste problem, there will still be activists lobbying against it.
The problems surrounding nuclear fission have solutions. We know how to dispose of the waste safely, but transport regulations and other hassles prevent us from doing it. The large quanitities of waste in storage are the result of policies which require low-level wastes to be stored along with the high-level stuff. If we isolated the high-level waste (spent fuel), the quantity would be quite small.
Given the hysteria and lack of understanding surrounding fission, I predict that if we ever get fusion working it will come under the same fire.
Whoa. I almost ceded without doing my homework.
It looks like trans/uranic fision results in about 200Mev and 1.5 spare neutons
And D-D Fusion yeilds only 18Mev and 1 spare nuetron. So your right. They’re not on the same order of magnitude. Fusion generates 10x more neutron radiation.
Ok. If hot fusion tokamak doesnt have control rods, but operates at 100,000,000K.
How does this open up the field to use different materials that “aren’t an option” in fission?
HLW, High level waste. They so cosy with the fuel that they are exposed to alpha and beta emmisions too. It also says that transuranics can get knocked around so violently that the fly through core walls. Yeeesh.
Also says that most of the radioactive waste comes from mining. Hmmmm.
Still trying to justify the words of the JET folks…
[corrections included in this quote for clarity]
Interesting indeed. Just to be a pain in the ass, I’ll point out that we haven’t addressed the issue of the relative efficiency of the two processes for producing usable energy. However, realistically I concede that the efficiency is unlikely to be very different, which suggests that for the same amount of power, you’ll get more neutrons with fusion.
The only thing that I was specifically thinking of were the control rods themselves. Fusion doesn’t require an object that specifically needs to become extrememly radioactive to serve its purpose.
This conflicts with the statement “let me point out that the bulk of the hazardous
waste generated by nuclear powerplants comes from the fact that neutron radiation rubs off on the equipment, the shielding , the building, everything!”, n’est pas?
Of course even if D-T fusion did turn out to be too radioactive, we still have the attractive option of
D + He-3 --> H + He + 18.4MeV
Yeah yeah, while technicly correct, the source I originally quoted, I suppose neglected that you have to have fuel and it has to come from SOMEWHERE. That what you get for trusting what you read on the internet.