Seriously confronting the perception that fusion is 50 years away, and always will be
Posted: 29 April 2012 11:03 PM   [ Ignore ]
Total Posts:  58
Joined  2011-10-11

[NOTE:  This post was originally made by Scott Hsu in December.  For some reason, upon reorganizing the forums and moving the post, it has now been attributed to me, and the date has changed.  I am looking into the reason for this technical difficulty.  Hope to fix it soon!]

Most people who make their way to this forum have likely heard the quip that “fusion is 50 years away and always will be.”  Earlier in my career as a plasma physicist, I used to simply dismiss those quips as coming from people who didn’t know anything, and that simply higher levels of funding would get us there sooner.  As I recently started to wonder more seriously about the origin of that quip, I now realize that even though higher levels of funding might get us there sooner, there are two main reasons why fusion has not been successful in obtaining those higher levels of funding, whether it be from government or private sources.

I believe that the first fundamental reason fusion is not taken seriously is that there is no fusion approach that has reached a sufficiently uniform level of readiness across all its critical required areas of science and technology.  For example, magnetic confinement (i.e., the tokamak) is the most scientifically mature and successful plasma confinement scheme, but the required plasma facing component (PFC) technology (along with its associated plasma-material interaction science) is difficult and is only starting to be addressed seriously by the mainline magnetic fusion program.  The high price tags and long lead times for both building high performance tokamaks and the needed, challenging R&D program in the PFC areas contribute to the reason why “fusion is 50 years away.”  On the other hand, there are proposed fusion approaches such as magneto-inertial fusion (MIF) that should cost much less than a tokamak, and by using thick liquid blankets surrounding the fusion plasma, MIF might largely avoid the PFC problems and required development program.  The problem with MIF is that it is scientifically immature, and that much research is still required to demonstrate a high performing MIF plasma system.  But an MIF reactor could ultimately be much less costly and time-consuming than a tokamak reactor, if we can muster the will and funding to advance the science and performance of MIF.

The second fundamental reason is that fusion plasma physics and engineering is difficult!  Early on in fusion research, scientists were falsely optimistic that all the problems were about to be solved.  It has taken about half a century of hard work by very smart people to push magnetic confinement plasma physics to where it is today.  I dare say that no other area of fusion science, including inertial confinement fusion (ICF), is at the same level of scientific maturity and sophistication as magnetic fusion science.  Every time scientists have tried to push the performance of their proposed fusion system, the plasma has found new ways to thwart them with newly discovered instabilities and other problems.  This might very well be what is happening with the National Ignition Facility (NIF) right now in their quest for ignition (and I sincerely hope they achieve it soon).  We as fusion scientists must be honest with ourselves and respect nature.  Until we demonstrate the level of plasma performance for fusion needed by any fusion approach, it is simply too premature to put a timeline on it.  We need to do the serious scientific research for many fusion approaches so that other approaches have a chance to reach fusion conditions.  Hopefully some of these other approaches have easier and less costly paths to a reactor than does a tokamak.  The difficulty with the science and engineering, however, places fusion in a catch-22 situation with respective to attracting private investment.  If scientists tell the truth about any given fusion concept that the scientific risk is still high, then private investors will shy away.  In order to convince most private investors to invest, scientists have to oversell and promise a fast-track schedule, and then when the physics turns out to be elusive and more difficult than anticipated, the promised timeline is not realized, and fusion gets another black eye.  I hope this doesn’t happen to General Fusion, which will soon be entering the phase of testing the most difficult physics of their approach.

Thus, to recapitulate, for most of the history of controlled fusion research (some 50+ years), fusion has been and still is 50 years away.  To continue on our present path of worldwide fusion development will not alter this entirely correct perception.  To seriously confront and overturn it, there are a few things that all fusion proponents should do:  (1) commit themselves to bringing all critical areas needed for a fusion reactor to equally advanced levels of technological readiness (otherwise fusion will always be a science and not energy program), (2) for proponents of non-tokamak fusion concepts, don’t oversell the readiness of your favored approach, but rather work toward establishing and demonstrating the scientific understanding needed to field a fusion-relevant experiment, (3) re-examine inherent biases we all (especially mainline tokamak and ICF proponents) might possess about various fusion approaches with the goal of enabling a more level playing field for the less mature ideas, and (4) think of ways to help open up new models of funding for fusion without overselling, from both government and private sources.