Lawrence Livermore NIF laser fusion experiment delivers record energy output
powersystemsdesign.com
powersystemsdesign.com
I was a little flabbergasted at the overall progress of the laser fusion research program: apparently back in the early '70s, the first LANL people predicted that you could achieve laser fusion with just 1kj of input. Millions were spent, ignition was nowhere near, so they got funding for another, bigger laser, which failed too, so they got funding for more lasers, and those failed too, so they got funding for an even bigger multi-billion dollar laser called NIF, and not only has that failed to reach ignition once as promised - despite going up to 1.7mj (quite a long way from 1kj) - LANL managed to run over budget by at least 400% and took something like a decade longer to finish NIF than promised!
Any similarity between NIF and a practical Fusion Reactor is purely accidental.
Second, if anyone would like to see an inspirational speech given by NIF Director Ed Moses on how you move from theory to a a working reactor based on this technology, he spoke at Long Now in SF a few years ago:
http://fora.tv/2010/06/16/Ed_Moses_Clean_Fusion_Power_This_D...
Congress opted instead to fund it as a weapons-related program, but that doesn't mean that's all they're doing, and for a while they were explicitly spending the majority of their efforts on achieving energy gain. Recently they missed a deadline set by Congress which redirected the program to be only 20% for energy.
A really great history of the U.S. fusion program, from the 1950s to about 2012, is Search for the Ultimate Energy Source by Stephen O. Dean, who was deeply involved with much of it. http://www.amazon.com/Search-Ultimate-Energy-Source-ebook/dp...
Can you back this statement up?
But I should probably say "many" rather than "most," since he didn't give actual numbers.
You challenged the idea that a DoD project is indeed defense-related by citing (but not really) an obscure book that maybe says some scientists involved with NIF really believe it's for energy production. Forgive me if I'm not convinced.
TL;DR - More money -> likely fewer results.
Large organizations tend toward waste, delay and mediocrity. Without a profit motive and a mission to deliver a specific solution, the modus operandi is to grow as big of a budget pyramid as possible while providing just enough press releases to keep the DOE gravy-train rolling.
This is why high beta and other approaches from smaller groups may likely crack the problem, despite not having all of the toys (and distractions).
I have seen 9 figure / 7 year internal projects silently scuttled as to not create a "failure", despite delivering nothing. I have seen 6 figure projects surpass 8 figure projects through a combination of talent and leadership. I've seen duplication of systems merely because two depts can't find a way to work together, effectively doubling costs.
Depends on the meaning of "success." "Success" of a political project is rarely based on results; all projects are "successful," because the unsuccessful ones disappear. Real success, as in achieving an novel aim, is another matter.
Success is great, but at too high of a cost, it may make the results bitter (bodies in the Great Wall, pushing $10 billion total spent on NIF without results). This is where private R&D excels: there's a defined goal, time/cost pressures and usually fewer political constraints. This is why high beta has a higher probability of success AND a lower cost of success (better value/$).
What do you think is reasonable price tag for the development of an entirely new form of clean energy?
Saturn V might have worked, but justifying costs of one program with historic waste of another is still an invalid argument in the context of cost of success.
[0] http://www.nasa.gov/pdf/169943main_NASA_Virgin_Galactic_MOU....
"In the nanoseconds that followed, the capsule imploded and released a neutron yield of nearly 3x10^15, or approximately 8,000 joules of neutron energy..."
[...]
"These promising returns were the result of a laser experiment that delivered 1.7 megajoules (MJ or million joules) of ultraviolet light..."
More numbers: https://en.wikipedia.org/wiki/National_Ignition_Facility#NIF...
1.7 megajoules is about 400 kilocalories, or a king size Kit Kat bar. This is the energy of a car going 140 miles per hour. This is about 7 cents of AC power.
Wow. How can those two things be equivalent? I know there's a lot I don't know about physics...
But yes, the comparison is supposed to be to put in natural contexts, and so this is flawed example since we don't really live in space.
2) think about all the things you could do in the hour or so that a king sized Kit Kat bar could keep you energized;
3) visualize the trillions of cell-sized actuations required to perform each step of each task previously listed, and the neural computation required to organize these actions;
4) compare that with the relative simplicity of turning wheel axels to propel a car down the road;
5) marvel at the power of a Kit Kat bar powering the magnificent machine that is you.
140 mph is not a small number; to the power of two it's rather large. Now multiply the result by the mass of a car, which is still pretty huge even halved.
A racing car barreling down the speedway packs a hell of a punch.
Well, a kitkat bar actually has a decent amount of energy in it. Very roughly, the same energy as the same mass of wood, or gasoline. Chemical fuels don't vary too much in terms of energy density. They stay within the same order of magnitude, at most.
And yes, food is chemical fuel.
Probably only a straight-up chemical fuel like gasoline or methane packs more punch per gram.
The energy density of Kit Kat is 22 MJ/Kg (5.2 Kcal/g) http://www.wolframalpha.com/input/?i=%28Kit+Kat+calories+to+...
TNT has 2.8 MJ/Kg in an explosion and 4.2 MJ/Kg in a combustion. It has too much Carbons. In an explosion, it doesn’t react with the oxygen in the air, because it’s too fast. There is an interesting discussion in http://en.wikipedia.org/wiki/Trinitrotoluene#Energy_content
In general, the explosives have to explode without using the Oxygen in the air, so they have a lot of Oxygen and Nitrogen atoms inside. The fuels for slow combustions can have almost only Carbon and Hydrogen atoms to store the energy more efficiently and get the Oxygen from the air.
Nitroglycerin has less Carbons, so has more energy density. Mixed in dynamite has 7.5 MJ/Kg and alone has 6.4 MJ/Kg (Is this correct? I expected a bigger value).
I found a list of these values for a wide range of materials. In particular it says that green wood has 10 MJ/Kg, air dry wood has 15 MJ/Kg and oven dry wood has 20 MJ/Kg. http://physics.info/energy-chemical/
Other values: Gasoline ~45 MJ/Kg, Methane 55.5 MJ/Kg, Hydrogen 142 MJ/Kg
assuming ~4000lb[1] car, 140mph ~= 62.6m/s,
0.5*m*v*v = 0.5 * (4000*0.454) * 62.6^2 = 3.5E6Joules[2]
~= 830kcal
Did you miss the 0.5, or use a different Spherical Co^Wstandard automobile mass?Which is still only 2 kitkats :)
The other potentially confusing thing (judging by the sibling comments here) is that this isn't the energy required to accelerate an actual car from 0 to 140mph. It's the kinetic energy embodied in a car traveling at that speed. Wind & tyre resistance losses, engine/transmission, etc, etc. It's really the (upper bound of the) amount of energy you could expect it to impart if it hit something, or the amount of heat the brakes would need to dissipate to stop it.
Finally, for all those commenting on how much energy there appears to be in a kitkat, consider the famous E=MC^2, and just how staggeringly huge that C^2 term really is (9E16J/kg, if you're wondering) Getting all that out in a usable form, however, is left as an exercise for the reader.
[1] http://www.nytimes.com/2004/05/05/business/05weight.html
http://hypertextbook.com/facts/2000/YanaZorina.shtml
[2] http://www.wolframalpha.com/input/?i=0.5+*+%284000+*+0.454%2...
Anyone who has used a treadmill at the gym will recognize that it's a lot of work to burn off 400 calories. Not enough to get a car up to 140 MPH because the body isn't 100% efficient.
Not that these guys are in any rush to produce practical reactor as they are also mostly nuke weapons research, yet as a side effect they have been making very interesting and meaningful progress during last 15 years. The machine itself isn't for fusion research, it is for X-ray generation, and it just happens that it generates so much and so efficiently that it seems they couldn't resist and finally started trying mini Teller-Ulam :)
https://www.llnl.gov/news/newsreleases/2013/Aug/NR-13-08-04....
in 1.7 MJ
out 8 kJ
Q = 0.00444_
NIF has a program cost (1997-2013) on the order of $8B USD to reach this unimpressive number. (Based on $450m/yr not including fixed/one-time costs.)
JET is in for about $20B USD ($15B €). [0]
JET might be around thrice as costly, but the results speak for themselves.
[0] http://www.efda.org/fusion/why-should-society-invest-in-fusi...
(At least if the world disappears due to a crazy physics experiment one day, metaphysical archaeologist sensors in some parallel dimension who became aware of the event might see that we weren't entirely disrespectful!)