I really believe that fusion will come in forms smaller, cheaper, and sooner than most energy analysts now anticipate.
Some people like the idea of fusion and an abundant energy generator that produces non-radioactive helium as its nuclear waste. What is less exciting is the fact that only one type of nuclear fusion has ever produced net energy (more energy out of the fusion experiment than it takes to run the fusion experiment). That form of fusion is "impure fission-fusion" that uses the power of fission to create the conditions needed for fusion.
There is real reason to be optimistic about fusion today (not just hype and rah-rah). Several small fusion experiments are getting genuinely close to achieving "break-even" and fusion ignition.
Here is a link to an article at The Next Big Future Blog that does a good job reviewing the current status.
http://nextbigfuture.com/2013/05/nuclear-fusion-summary.html
Fusion has a real advantage over fission today as regards the current level of regulatory obstruction from NRC.
While this may not seem significant, it could make a real difference in how quickly fusion will emerge as a commercial technology in forms people will want to build and own to produce power.Some of the small, low cost fusion approaches are getting genuinely close to fusion ignition and practical power generation [1].
One of the keys to practical production of fusion power is to meet the basic conditions required for fusion (the famous Lawson criteria of temperature, plasma pressure, and confinement time). At least one small fusion experiment at Lawrenceville Plasma Physics headed up by Dr. Eric Lerner has at this point technically already met the minimal conditions for D-T fusion.
D + T -> 2He-4 (3.5 MeV) + neutron (14.1 MeV)
The Lawson criterion for fusion ignition and break-even with D-T fusion is about 4 x 10^15 keV s/cm^3.
Eric Lerner of Lawrenceville Plasma Physics reports in peer reviewed literature that his experiment has achieved 5 x 10^15 keV s/cm^3
This report makes things sound like LPP has achieved the long sought fusion goal of break-even energy already, but (as usual) things are more complex than a single number like Lawson criteria.
First off, the temperatures LPP has achieved are actually too hot for ideal D-T fusion. At 150 keV they would need longer confinement times and/or higher densities than they have
achieved (or so far announced) to reach break-even. So if they were actually looking to produce fusion ignition via D-T fusion they would aim to make their plasma a little cooler and a little denser.
In theory, LPP should not be that far away, but they are not putting effort into D-T or D-D fusion at this time (although in the past they have made many runs using both D-T and D-D fusion). D-T fusion is the fusion reaction that is easiest to achieve - but LPP is not currently interested in going that direction.
That's because LPP isn't really interested in D-T type fusion. The "problem" with D-T fusion is that a lot of the energy in D-T comes in the form of 14.1 MeV high-energy neutrons, which tend to make reactor materials highly radioactive via neutron activation. In theory you can capture that energy the same way you do with a conventional nuclear reactor (that is, by using the radiation to get something like liquid Lithium hot and using it to boil water or heat molten salt to run a turbine). Part of the problem with D-T fusion is the tritium itself, which is radioactive unlike deuterium fusion fuel, and LPP doesn't want to get into all those radioactive-materials handling issues. Tritium is also very expensive to purchase (about $30,000 per gram as estimated by Los Alamos National Lab).
So LPP has chosen to set their sights just a bit higher. They plan to bypass easier to achieve D-T and the cheap and very sustainable D-D fusion reaction in favor of aneutronic fusion (for me, the is a questionable and perhaps unfortunate choice - neutronic fusion producing a huge number of high value neutrons is valuable and could be used for applications like nuclear waste burning, medical isotope production, and manufacture of fuel for fission reactors, as well as producing electricity from fusion).
The fusion reaction LPP prefers is called p-B-11, which uses conventional hydrogen (which becomes a bare proton, p, when ionized) and boron-11, which is over 100X more difficult to ignite in a tokamak (and is about 20X as hard to ignite in a properly designed Inertial Confinement Fusion device).
[1] - LPP at Google's Solve for X Conference - still leading the field -
http://www.lawrencevilleplasmaphysi...olve-for-x-conference-still-leading-the-field
).
