Guest essay by Eric Worrall
Inertial confinement fusion researchers have claimed a near break even experimental nuclear fusion burn, in which energy produced by the fusion reaction was comparable to the energy injected to initiate the burn.
National Ignition Facility experiment puts researchers at threshold of fusion ignition
On Aug. 8, 2021, an experiment at Lawrence Livermore National Laboratory’s (LLNL’s) National Ignition Facility (NIF) made a significant step toward ignition, achieving a yield of more than 1.3 megajoules (MJ). This advancement puts researchers at the threshold of fusion ignition, an important goal of the NIF, and opens access to a new experimental regime.
The experiment was enabled by focusing laser light from NIF — the size of three football fields — onto a target the size of a BB that produces a hot-spot the diameter of a human hair, generating more than 10 quadrillion watts of fusion power for 100 trillionths of a second.
“These extraordinary results from NIF advance the science that NNSA depends on to modernize our nuclear weapons and production as well as open new avenues of research,” said Jill Hruby, DOE under secretary for Nuclear Security and NNSA administrator.
The central mission of NIF is to provide experimental insight and data for NNSA’s science-based Stockpile Stewardship Program. Experiments in pursuit of fusion ignition are an important part of this effort. They provide data in an important experimental regime that is extremely difficult to access, furthering our understanding of the fundamental processes of fusion ignition and burn and enhancing our simulation tools to support stockpile stewardship. Fusion ignition is also an important gateway to enable access to high fusion yields in the future.
“This result is a historic step forward for inertial confinement fusion research, opening a fundamentally new regime for exploration and the advancement of our critical national security missions. It is also a testament to the innovation, ingenuity, commitment and grit of this team and the many researchers in this field over the decades who have steadfastly pursued this goal,” said LLNL Director Kim Budil. “For me it demonstrates one of the most important roles of the national labs – our relentless commitment to tackling the biggest and most important scientific grand challenges and finding solutions where others might be dissuaded by the obstacles.”
While a full scientific interpretation of these results will occur through the peer-reviewed journal/conference process, initial analysis shows an 8X improvement over experiments conducted in spring 2021 and a 25X increase over NIF’s 2018 record yield.
“Gaining experimental access to thermonuclear burn in the laboratory is the culmination of decades of scientific and technological work stretching across nearly 50 years,” said Los Alamos National Laboratory Director Thomas Mason. “This enables experiments that will check theory and simulation in the high energy density regime more rigorously than ever possible before and will enable fundamental achievements in applied science and engineering.”
The experiment built on several advances gained from insights developed over the last several years by the NIF team including new diagnostics; target fabrication improvements in the hohlraum, capsule shell and fill tube; improved laser precision; and design changes to increase the energy coupled to the implosion and the compression of the implosion.
“This significant advance was only made possible by the sustained support, dedication and hard work of a very large team over many decades, including those who have supported the effort at LLNL, industry and academic partners and our collaborators at Los Alamos National Laboratory and Sandia National Laboratories, the University of Rochester’s Laboratory for Laser Energetics and General Atomics,” said Mark Herrmann, LLNL’s deputy program director for Fundamental Weapons Physics. “This result builds on the work and successes of the entire team, including the people who pursued inertial confinement fusion from the earliest days of our Laboratory. They should also share in the excitement of this success.”
Looking ahead, access to this new experimental regime will inspire new avenues for research and provide the opportunity to benchmark modeling used to understand the proximity to ignition. Plans for repeat experiments are well underway, although it will take several months for them to be executed.
Source: https://www.llnl.gov/news/national-ignition-facility-experiment-puts-researchers-threshold-fusion-ignition
I find inertial confinement fusion exciting, because in principle, unlike magnetic confinement fusion, it might be possible to scale inertial confinement down to an affordable size.
The gigantic international magnetic confinement ITER tokamak currently being constructed in France in a sense represents a brute force approach to viable nuclear fusion. The heat produced by a nuclear fusion reaction is related to the volume of the plasma, while the heat lost is related to the surface area. Simple geometry dictates that if you make the plasma volume really large, the heat generated by such a large volume of fusing plasma is more likely to overcome surface losses, leading to a self sustaining fusion reaction.
My concern with this magnetic confinement approach is that even if ITER succeeds, the sheer size and cost of the precision engineered reactor vessel will represent a formidable barrier to adoption. Nuclear fusion reactors which cost $50 billion each and take decades to construct are unlikely to contribute significantly to the global energy mix, so long as cheaper options are available.
There is also a real risk that after all these billions of dollars of expenditure and man millennia of effort, ITER’s most expensive components will simply disintegrate under the blast of radiation from a sustained fusion burn. Deuterium Tritium fusion produces a blizzard of hot neutrons, which are more than capable of causing physical structural damage to anything near the plasma. The search for structural materials which can survive such a hostile environment without collapsing into dust is ongoing.
The Lawrence Livermore facility which produced the near break even burn is large, but it is a lot less expensive than the ITER facility.
Lawrence Livermore still have a long way to go to prove that inertial confinement is a viable path to connecting an operational nuclear fusion reactor to the national grid. Although the energy produced was comparable to the energy deposited to initiate the burn, the lasers which deposited that energy are not 100% efficient. The total energy expended conducting the experiment likely vastly exceeded the fusion yield.
An inertial confinement fusion generator would have to economically perform thousands of burns per day, rather than a single exciting experimental burn. And of course we still don’t know how much a net energy producing inertial confinement fusion reactor would cost, even if such a thing is possible.
Correction (EW): h/t Eric Lerner, fixed the link and the story – I accidentally copied in an old story.
What a pipe dream! Until the breakeven point is reached, the cost per KW/h is infinite, once it is reached it is almost infinite ..
BTW, in both techniques the plan is to extract the energy by moderation in water, liquids will not be damaged by neutrons. The wall materials as basically transparent for neutrons, just like the structural components in a nuclear reactor, which see similar flux and energy
I think the hope from this non serious hype is a fools errand. I believe the fact gazillions of dollars and person-hours have been devoted to this and decades of work without even breaking even – suggests the theory upon which they are operating is incorrect.
Thus none of these avenues is going to work. To get electrical power output you have losses. If you assume steam turbines would be employed and then driving conventional generators – say the fusion to steam to shaft power is 45% efficient, then generators are 90% efficient you have only 0.405 of the energy produced as net electrical power. The reciprocal is then 2.47.
This means to be able to generate electrical power the so called fusion reactor needs to be 247% more output than input. A far cry from break even!
If the concepts ingrained in the dogma of the standard model and nuclear and astrophysics are wrong – then no amount of “more money” and “more power” are going to produce gainful results.
Just like how Einstein showed Newtonian physics was flawed or incomplete, one of his axioms applies to this hot fusion fiasco: “Insanity is doing the same thing over and over again and expecting different results”
I can state flatly that heavier than air flying machines are impossible.
— Lord Kelvin, 1895
Go with the substantial fusion tech we have and use existing mine tech. A small hydrogen bomb to melt a liquid chamber 5 – 7km down into a massive granite body, and pre-rigged with a suitably located ‘shell’ of coolant piping in the surrounding granite outside the chamber. Aim for a century of operation.
Near only counts in horseshoes, hand grenades, and thermonuclear bombs.
That’s what we said when I was growing up in the 60s and 70s.
Can we add fusion reactions?
What is near? 90% or 60%?
“I find inertial confinement fusion exciting” … because of the potential to end life on earth as we know it if the experiment goes wrong?
In researching what happens as this massive laser power is focused onto a small spot, they discovered that they can also be particle accelerators. At the time, the warehouse machines were PetaWatt sized, and a smaller research outfit had built a smaller ‘tabletop’ 10TW machine that also proved to be a particle accelerator.
The table was 5m x 10m. Space will be needed to stretch the pulse out in time, amplify it and then focus it in time and space. The wall to laser efficiency was 1%. It fired at 10Hz. Increasing that last was a technical challenge that no researcher was pursuing at the time. The limit at the time was the mirror that focused the beam in time and space. The lead author’s next goal was to make a ‘tabletop’ PW laser. I haven’t followed to see if that has been achieved.
I will skip the reasons why it wasn’t yet at the point where it could compete with commercial isotope producing particle accelerators. There were many papers recommending the PW laser as ideal for the source and initial accelerator feeding large research particle accelerators. Roughly the same as the only part of the SSC that was built before Congress canceled it, source and 70 MeV linac.
That 1% wall to laser power efficiency is going to be a royal pain in producing energy. So will the conversion efficiencies from fusion energy to electrical energy. And the power to run itself will need to be subtracted to consider how much energy it can deliver.
Not sure what the big machine rep rates are. At the time, one of the large European facilities scheduled 7000 shots per year. Probably better than 1/hr if you throw in maintenance and other down time.
Is there any real scientific information derived from this 70 year boondoggle? If not, then it is long past time when the plug should be pulled in this.
They will NEVER turn this into real power generation. Enough of these big toys for the unemployable surplus physicists.
It is apparent to me that the possibilities of the aeroplane, which two or three years ago were thought to hold the solution to the [flying machine] problem, have been exhausted, and that we must turn elsewhere.
— Thomas Edison, November 1895
The statements here help explain why inertial confinement will not provide grid-scale power production.
https://str.llnl.gov/january-2016/nikroo
“…conditions similar to those in stars and detonating nuclear weapons.”
“NIF is the paramount experimental facility in the National Nuclear Security Administration’s Stockpile Stewardship Program to ensure the continuing safety, security, and effectiveness of the nation’s nuclear weapons.”
The exceptionally high level of engineering involved is astonishing. They are doing very good work. However, it is not breakthrough work for fusion power generation.
The kill shot:
” Although the energy produced was comparable to the energy deposited to initiate the burn, the lasers which deposited that energy are not 100% efficient. The total energy expended conducting the experiment likely vastly exceeded the fusion yield. ”
As in that admission should kill this boondoggle. Other commentors noted that the lasers used 400x the output. 0.25%…….
Did everyone miss this hiding in plain sight?
advance the science that NNSA depends on to modernize our nuclear weapons and production
So if we can extend that ONLY a quadrillion times longer we can get close to the energy availability of solar.
Not a eureka moment but worthy.
This is science at work and modernizing nuclear weapons is a good idea!
Any useful means of generating power may result with improved material to contain high temperatures is preferable to land grabbing windmills and solar panels that don’t come cheap with intermittent usefulness and short life.
Cheap clean power may not come in our lifetime or in a millennium but if we don’t lose our grip on science it will happen. Once the scientists solve it the engineers will make it useful. With the help of mathematicians and craftsmen.
“Near break even?” That’s better than what we get with renewables. Sign me up!
Lest we fall prey to being impressed by units of megajoules, I’ll just point out that the 1.3 MJ of “yield” in the above quoted PR from LLNL/National Ignition Facility is equivalent to heating about 4 liters of water from 20 °C to the boiling point of water (but not boiling off any of that water).
As they say, it’s a start (pardon the pun).
For the interested: https://www.nap.edu/read/18288/chapter/6
” It is the understanding of this panel that the current program plan anticipates a demonstration of ignition sometime after the beginning of FY2013,” not even close.
I’m not even gonna say it.
The spherical tokamak being developed in the UK might be a better route to fusion power generation – if this is even possible.
Mast Upgrade: UK experiment could sweep aside fusion hurdle – BBC News
A small step forward and a big waste of money. I would like to see my tax dollars spent on a thorium molten salt fission reactor prototype – much more likely to see some real return on the investment. Now if they could only talk about fusion as a nuclear reaction instead of burning or ignition, which are entirely different chemical reactions from nuclear fusion.
https://www.nature.com/articles/d41586-021-02338-4