Slashdot Mirror
Fusion and Fission/LFTR: Let's Do Both, Smartly
TheRealHocusLocus writes: Disaster preppers have a saying, "two is one and one is none," which might also apply to 24x7 base load energy sources that could sustain us beyond the age of fossil fuel. I too was happy to see Skunkworks' Feb 2013 announcement and the recent "we're still making progress" reminder. I was moved by the reaction on Slashdot: a groundswell of "Finally!" and "We're saved!" However, fusion doesn't need to be the only solution, and it's not entirely without drawbacks.
All nuclear reactors will generate waste via activation as the materials of which they are constructed erode and become unstable under high neutron flux. I'm not pointing this out because I think it's a big deal — a few fusion advocates disingenuously tend to sell the process as if it were "100% clean." A low volume of non-recyclable waste from fusion reactors that is walk-away safe in ~100 years is doable. Let's do it. And likewise, the best comparable waste profile for fission is a two-fluid LFTR, a low volume of waste that is walk-away safe in ~300 years. Let's do it.
Why pursue both, with at least the same level of urgency? Because both could carry us indefinitely. LFTR is less complicated in theory and practice. It is closer to market. There is plenty of cross-over: LFTR's materials challenges and heat engine interface — and the necessity for waste management — are the same as they will be for commercial-scale fusion reactors. To get up to speed please see the 2006 fusion lecture by Dr. Robert Bussard on the Wiffle ball 6 plasma containment, likely the precursor to the Skunkworks approach. And see Thorium Remix 2011 which presents the case for LFTR.
All nuclear reactors will generate waste via activation as the materials of which they are constructed erode and become unstable under high neutron flux. I'm not pointing this out because I think it's a big deal — a few fusion advocates disingenuously tend to sell the process as if it were "100% clean." A low volume of non-recyclable waste from fusion reactors that is walk-away safe in ~100 years is doable. Let's do it. And likewise, the best comparable waste profile for fission is a two-fluid LFTR, a low volume of waste that is walk-away safe in ~300 years. Let's do it.
Why pursue both, with at least the same level of urgency? Because both could carry us indefinitely. LFTR is less complicated in theory and practice. It is closer to market. There is plenty of cross-over: LFTR's materials challenges and heat engine interface — and the necessity for waste management — are the same as they will be for commercial-scale fusion reactors. To get up to speed please see the 2006 fusion lecture by Dr. Robert Bussard on the Wiffle ball 6 plasma containment, likely the precursor to the Skunkworks approach. And see Thorium Remix 2011 which presents the case for LFTR.
first, a fusion reactor can't "explode". It operates in a vacuum, and the amount of material fusing is less than a cup of deuterium gas (heavy hydrogen). If the fusing material does start to "explode", the fusion goes out and and the hydrogen dissipates in the vacuum.
Deuterium fusion has the lowest require startup energy, and produces the least amount of neutrons. The goal of fusion is the production of helium 4. The only stray neutrons come from making helium 3 - and that doesn't happen that often (it requires more energy to cause a deuterium nucleus to shed a neutron as it fuses with another deuterium nucleus).
>Disaster preppers have a saying, "two is one and one is none," which might also apply to 24x7 base load energy sources that could sustain us beyond the age of fossil fuel.
How does a non-nonsensical saying apply to energy? Explain yourself.
Monoculture is bad. Choosing one form of baseload generation to emphasize is bad, because however great it looks on paper, if some horrible problem emerges 10 years later, you're screwed. If all new powerplant construction for decades were split between 2 technologies, and one of them proved problematic, we have a "shipping, tested solution" to migrate to immediately. Expensive, but possible. All of which is even more true when it comes to designs that aren't yet production ready.
> I too was happy to see Skunkworks' Feb 2013 announcement and the recent "we're still making progress" reminder. I was moved by the reaction on Slashdot: a groundswell of "Finally!" and "We're saved!"
How did we move from crazy people sayings into nuclear energy? This is the worst written summary on /. in a very long time.
We need something not-fossil-fuel based that can be used by any city anywhere. (Yeah, yeah, solar and wind have their upsides, but there are plenty of cities where both are nonsense.) Fusion would be wonderful, but we should use "maybe oneday fusion" as any reason not to also pursue sane, modern fission designs. And regardless, we should pursue 2 unrelated technologies, because monoculture is bad.
Socialism: a lie told by totalitarians and believed by fools.
Actually pretty interesting numbers
http://nextbigfuture.com/2011/...
How the hell did this get modded insightful? It's full of total BS.
First, as the summary even pointed out, fusion will produce waste due to the high neutron flux. You didn't even read the summary, nor do you have the faintest idea what you're talking about.
Second, LFTRs were designed to NOT meltdown. In fact, you need to heat the piping in order to have the salt not freeze. Again, your statement that all fission reactors melt down is proof of your ignorance. You're full of FUD.
Third, they tested them. They just walked away. And it shut down by itself. No special magic, no SCRAM. Then they walked away for 40 years. And it didn't melt down. Instead, it froze. Yes, there were problems discovered later, like the evolution of fluorine gas--but these are not even on the same scale of challenges as preventing an inherently meltdown-prone PBWR from going south for the winter. Also, you don't need to use water as your coolant. As we all know very well, water is dangerously prone to turning into a fuel-oxidizer mix and going off.
Also, what would make you think that solutions need to be expensive? Why is THAT your criteria for a safe design? See, PBWRs are bad because they're inherently unstable. I hope we never build another. However, I'm still pro-nuclear, and I think that a LFTR is the way to go for now, since the design is inherently walk-away safe. Yes, there are materials challenges. You need to use special piping doped with 1.1% niobium and so on. But these are things we've researched and can continue to refine. Solutions should be judged on technical merit, not simply on, "it's expensive, so it must be good!"
Also, why the hell would you suggest launching old nuclear reactor parts into space? Which orifice did you pull that out of?
You're so full of FUD that I can only wonder which energy conglomerate you're shilling for. Care to tell us?
Unfortunately yes.
It is easy enough to get a big public outcry for any new nuclear plant, irrespective of its safety. The public has learned that nuclear = big accident (sooner or later). If you ask an activist if he want a coal or a nuclear plant, he will say 'neither' and fight both, but probably more vigorously against the nuclear one. That makes investing into any kind of nuclear stuff a very risky proposal.
The only way to change is when other fuels get expensive and we'll see rolling power outages again and the public experiences that we need new plants.
Markus
...fusion will produce waste due to the high neutron flux.
Not necessarily. The most viable fusion approach does not produce neutrons as a product of the reaction. In addition, they don't need to contain and stabilize the plasma which is the bane of most fusion programs. They intend to leverage the inherent instability of plasma to produce 200 small reactions or pulses per second. They won't need steam generators since most of the energy is released in the form of an ion beam.
... As I recall even thorium will only provide several centuries at 100%, though we could increase that by an order of magnitude by developing seawater extraction technology.
Good that you brought up seawater extraction technology. Using that we have enough uranium, even just using once-through burning, for something like a 10,000 year supply at current consumption rates. Increase nuclear power ten-fold (125% of current world electricity consumption) and it is still 1,000 years. If we implement breeding (we could get the bugs worked out in a few centuries I imagine) then we are back up 100,000 years or so.
Why does thorium need to enter the picture?
Second class citizen of the New Gilded Age
I believe you are wrong. Molten salt reactors are so safe it will take a comet / asteroid / military precision strike to cause a significant radioactivity release, and there is no water pressure on the inside to spit stuff out.
If you want to make the reactor 99.999999999999999% safe just bury it deeper. conventional reactors are too big to be buried, molten salts are compact enough you could install them 10 feet underground (with 10ft of reinforced concrete above it), and have all of its connections first go sideways before go up.
All three significant nuclear accidents (TMI, Chernobyl, Fukushima) wouldn't have happened with a molten salt reactor.
Coal kills. Natural gas kills. Oil kills. Coal kills 200k yearly worldwide. Natural gas and oil kills 10k yearly worldwide. When will we understand that fukushima radiation killed nobody and the real reason the quarantine is still going on is the result of unscientific fear of cancers that never materialized with any nuclear accident ?
Three Mile Island killed zero people, caused zero detectable deviation from cancer rates (specially no thryreoid or leukemia cancer rate deviations, main cancer types from radiation).
Chernobyl killed less than 200 people from radiation sickness and might eventually kill a whopping 6000 people from cancer compared to those that swear it kill one million, but can't list the names of even a couple thousand cancer cases (with names and diagnosis).
If people would be allowed back into Fukushima one year after the accident, cancer rates from that population would be smaller than those of people living in downtown Tokyo.
http://bravenewclimate.com/201...
http://en.wikipedia.org/wiki/F...
http://www.nbcnews.com/news/ot...
The problem isn't the disaster but rather Linear no threshold radiation cancer models which were created by deeply anti nuclear weapon scientists desperate to instill fear on governments undergoing nuclear weapons tests.
If LNT were true, cancer rates for people living above 10000ft / 3Km would be horrendous.