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Is It Time For the US Government To Back Fusion At NIF Over ITER?
ananyo writes "Laser beams at the National Ignition Facility have fired a record 1.875 megajoule shot into its target chamber, surpassing their design specification. The achievement is a milepost on the way to ignition — the 'break-even' point at which the facility will finally be able to release more energy than goes into the laser shot by imploding a target pellet of hydrogen isotopes. NIF's managers think the end of their two-year campaign for break-even energy is in sight and say they should achieve ignition before the end of 2012. However, with scientists at NIF saying that a $4 billion pilot plant could be putting hundreds of megawatts into the grid by the early 2020s, some question whether the Department of Energy is backing the wrong horse with ITER — a $21-billion international fusion experiment under construction at St-Paul-lez-Durance, France. Is it time for the DoE to switch priorities and back NIF's proposals?"
Perhaps a better idea, given the potential benefits of fusion research, would be for the DoE to throw their weight behind multiple projects, rather than sacrificing some to support others.
NIF itself isn't really the answer, though. It's great for super-dense matter studies and gathering information of use for nuclear bomb detonations, but if the goal is sustainable fusion, NIF's approach is too expensive and inefficient. Rather, you need to go with a variant like HiPER. NIF relies solely on a compression pulse. HiPER uses a compression pulse plus a heating pulse. This allows the compression pulse to be much smaller and easier to achieve.
Teach me to love you, you squishy poet from beyond the stars!
They don't.
Next question?
Teach me to love you, you squishy poet from beyond the stars!
Not just Thorium, and there's probably better designs out by now anyway, but I for one was very pissed and still am that Clinton canceled America's Integral Fast Reactor project. Because ohhh scary nuclear. Except the IFRs produce less waste, safer waste, and can be fed just about anything, including most the crap that right now is considered waste.
Bad project, Bill kill!
... still waiting for this free-as-in-beer free beer I keep hearing about.
Why the fuck do people keep on mentioning Thorium reactors? They still produce fission products. And fission products are the only thing that nuclear reactors need to protect against releasing to the public. Fission products are also statistically determined. You will always get short medium and long term radionuclides even if you burn up some.
There are benefits to Thorium reactors, but in a major accident they will still release enough highly radioactive substances that will require evacuation and quarantine of the affected area for decades. Yes, a thorium reactor can still meltdown, it still has decay heat, and it would require complex engineered safeguards to protect it.
You do realize that EXISTING thorium reactor designs -
1. Do not need water as coolant (hence no high pressure evironment and much smaller)
2. As designed will shutdown on their own with no outside intervention.
3. As designed they can't "overheat".
"Best results occur with molten salt reactors (MSRs), such as ORNL's liquid fluoride thorium reactor (LFTR), which have built-in negative-feedback reaction rates due to salt expansion and thus reactor throttling via load. This is a great safety advantage, since no emergency cooling system is needed, which is both expensive and adds thermal inefficiency. In fact, an MSR was chosen as the base design for the 1960s DoD nuclear aircraft largely because of its great safety advantages, even under aircraft maneuvering. In the basic design, an MSR generates heat at higher temperatures, continuously, and without refuelling shutdowns, so it can provide hot air to a more efficient (Brayton Cycle) turbine. An MSR run this way is about 30% better in thermal efficiency than common thermal plants, whether combustive or traditional solid-fuelled nuclear.[27]"
http://en.wikipedia.org/wiki/Thorium#Commercial_nuclear_power_station
4. The US has a metric fuckton of thorium in it's coal deposits.
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I've been around NIF and it is an amazing machine. It's also designed (and funded) to study warm dense matter physics like equations of state at high density for nukes, not fusion. Use of NIF for fusion is a great side-benefit and hopefully they can get useful data from it.
The HiPER project to design a fusion reactor based on fast ignition has been though an initial concept design phase, but is now waiting further development. There is still a lot of research which needs to be done in target physics, lasers, and materials before ICF is ready to build an ITER-like machine
The physics behind the ITER tokamak on the other hand is quite well understood at this point. Sure there are outstanding issues which are still being worked on (ELMS, divertor detachment, RWM control spring to mind) but we're pretty confident it will work. The design of ITER started in 88, and before that the INTOR project in '78, but it has taken a long time for politicians actually put some serious resources behind it. Hopefully it won't take that long for ICF projects like HiPER to be taken seriously and funded at a level which will make them happen