Wednesday, 14 September 2011

Fusion and 'the 30 year problem'

Nuclear fusion made the news again this week but the one thing that the news item shows is that the 'inertial fusion' (or as they sometimes call themselves 'laser fusion') people are much more active at public relations than the 'magnetic confinement' community.

That doesn't mean that they are closer to the goal of making fusion a commercial reality.  Realistically speaking, both approaches can predict a similar timescale to reach fruition, and I personally believe that it is important that both are pursued with vigour - greater vigour than they currently have.

The BBC news article UK joins laser nuclear fusion project is a good example of making news out of a classic non-announcement.  Laser fusion research in the UK is rather in the doldrums at the moment, significant funding not being forthcoming.  One might conclude that this has resulted in certain leaders of the HIPER project going over to work at the National Ignition Facility, contributing to the continuing brain-drain from UK.  NIF is close to its first operation, but to paraphrase the industry 'joke' that 'fusion is 30 years away and always has been', fusion (or ignition) at NIF is one year away, and let's face it . . . it has been for several years.  If I remember correctly, the latest delay was due to a concern about something called 'sky-shine' - not a new problem that had not been considered but something that had been analysed a decade ago.  It was probably just a scare story of the type that often delays progress in anything that the public does not understand. 

NIF also benefits from funding from military sources to pay for its multi-billion dollar price tag.  Even though only a few percent of its operational time will be spent on military work they have gone to the huge expense of a second independent control room to protect the 'classified data' that they will collect to teach them how to make better hydrogen bombs.  (Does this explain the interest of the UK's AWE now?)  Meanwhile magnetic fusion has no military applications at all and can't gain from such funding.

If there is one thing to demonstrate the media hype from NIF I can tell you this.  I have personally visited the facility, after seeing a series of presentations about it, heard about how huge and impressive it is, how it is going to be the answer to the world's energy problems and seen numerous stunning photographs.  It was a nice facility but I was totally 'underwhelmed' by it.  It is much smaller than I had been led to expect. However, I wish them well and would not be at all surprised if they achieve 'ignition', for a short period, earlier than the magnetic confinement devices achieve the same. When I say a short period though, it will be for a micro-second or so, not really rivalling  the current record of 16 MW for 1 (whole) second on JET.

The other good news is that there is now hope on the horizon for magnetic confinement fusion too.  This '30 year problem' (not 50 years as the BBC claimed) might actually be realistic at last.  I don't say this out of sheer optimism, but from the observation that the world has now started to take the issue a little bit more seriously and the ITER project is progressing quite well now.  International squabbles aside, there are actual buildings on the site and at long last a commercial reactor-sized tokamak is finally being built.  In about 10 years time we will know a lot more about the feasibility of magnetic confinement fusion.

When I said 'a little bit more seriously' we have to set the spending in context.  In total, ITER is costing as much as one beer per year for each person in Europe.  Its quite a lot of cash but as it is spread over a period of two decades it is not all that much per head  This is especially true since this cost is spread between the governments representing half the world's population, and not just Europe.


The international media has missed another important real event on the subject.  The most successful tokamak in the world so far is based at Culham in Oxfordshire.  The strange thing is that this 'break-even' sized device, called JET, is still in many ways the 'state-of-the-art' in spite of the fact that it has been operating since 1983.  This is a testimony to the design of this incredible machine.  At the time it was 100 times larger (in volume) than any previous machine.  Now, 28 years later, it is the only tokamak in the world capable of running with the 'real fusion fuels' of tritium and deuterium. All the other tokamaks in the world produce good data too, but JET is currently the closest to ITER in almost every way.  (ITER will be only 10 times larger than JET in volume.)

Just 3 weeks ago JET went back into operation after a 2 year shutdown to upgrade its internal components and its heating systems.  By all accounts, the first weeks of experiments are producing excellent data.  You can bet that the people at ITER are keen to get their hands on the intellectual property that is being gained there.

But the media have commented on this almost nowhere!  A few techy journals have mentioned it, but real progress on a real machine has not had the world-wide coverage that has been achieved by the non-existent UK device called HIPER.  HIPER should perhaps be renamed HYPEr.

Our relatively small machines have paved the way for real progress towards a plausible future energy source.  Fairly detailed and credible designs and project plans for a machine like ITER - which is big enough - have been available for at least 20 years, so . . .

Progress in fusion is not being held back by the technologists as much as by lack of funding and ambition of the governments setting the targets! 

There is one message that we should all keep in mind.  There is a global energy crisis coming and it is coming soon.  Many people reading this will experience it in their own lifetimes.  If we as a race do not invest much more heavily in developing alternative energy of all kinds it will be difficult to see how humanity can survive.

Governments should be setting aggressive and competitive targets and asking why the technologists have not solved the problems - whereas at the moment it is, to a larger extent, the technologists begging for breadcrumbs to make any progress at all.

This isn't a game and it isn't a hobby for pure scientists.  Seriously!  This is a matter of life and death.


Stuart said...

Very nice article! I totally agree that there isn't enough on JET in the newspaper. The only article of note I can remember for a while now was written in August by the Guardian's Leo Hickman, giving a brief interview with Steven Cowley about the JET restart ... didn't exactly make many headlines.

When you say though, rivalling the current record on JET of 16 MW for 1 second, in fairness this wasn't ignition. So if NIF does achieve a Q > 1 then, I guess credit due where credits due, even if it is just for a micro-second or so.

"HIPER should perhaps be renamed HYPEr."

Like it!

Plasma Engineer said...

Thanks Stuart. Yes I agree that Q=1 will be very creditable.

But of course the 'real' break-even point (accounting for the construction and decommissioning energy etc) is more like Q=4.

(For those who want to know what we are talking about, see tomorrow's post, "In fusion, size really matters!" for an explanation of Q.)