Science-Watching: From Ignition to Energy

[from Science & Technology Review July/August 2025 Research Highlights, by Noah Pflueger-Peters]

Achieving ignition at the National Ignition Facility (NIF) proved that harnessing the power of the Sun in a laboratory may be possible. The Sun’s extreme temperatures and pressures cause light elements to fuse together to create heavier ones, releasing enormous energy and sustaining conditions for more thermonuclear reactions. NIF replicates these conditions with inertial confinement fusion, in which lasers compress and heat a target capsule filled with deuterium and tritium (DT), “heavy” isotopes of hydrogen that contain extra neutrons. When the isotopes fuse, they create helium and a neutron, and the lost mass is converted into inertial fusion energy (IFE), which can be harnessed for energy production.

Nuclear fusion produces significantly more energy than either nuclear fission or burning fossil fuels for equivalent amounts of fuel. Since the input materials for fusion energy are plentiful on Earth, an IFE power plant could produce safe, abundant, power grid-compatible energy without highly radioactive byproducts.

Although significant work remains to harness fusion energy, pursuing the development and deployment of IFE is crucial for the nation’s energy security, enabling the United States to shape implementation worldwide, avoid technological surprises from adversaries, and influence technical leadership in other energy-intensive technologies such as AI, machine learning (ML), and supercomputing.

IFE research stretches back to the early days of Lawrence Livermore, and today the Laboratory is fostering the overall fusion ecosystem. Livermore’s unique capabilities, expertise, and connections will be critical to laying the technical, logistical, and legal groundwork to make IFE possible. “IFE is a grand scientific and engineering challenge, something that is so incredibly difficult and high-risk and takes enormous expertise,” says Tammy Ma, Livermore’s IFE Institutional Initiative lead. “This challenge makes it the right kind of problem for national laboratories to pursue.”

This artist’s rendering shows the concept for an inertial fusion energy (IFE) power plant design, with a cutaway to show the plant’s target chamber in the center. Livermore researchers are laying the groundwork for private fusion companies to build similar designs. (Illustration by Eric Smith.)

Designing for Viability

NIF is the only facility to date to demonstrate the ignition and burning plasma conditions that are prerequisites for IFE, but it is an experimental facility for stockpile stewardship research, not a power plant. To be commercially viable and produce the energy to offset costs and meet demands (baseload power), IFE plants will need to generate more than 30 times the energy they deliver to the fusion target on every shot while firing 10 or more shots per second, compared to NIF’s rate of one or two shots per day.

The Laser Inertial Fusion Energy (LIFE) study, conducted between 2008 and 2013, aimed to build directly on technology developed for NIF to achieve IFE and took a systematic approach to this requirement by developing the Integrated Process Model (IPM). (See S&TR, April/May 2009 [archived PDF], pp. 6-15.)

IPM is a technoeconomic model of an IFE power plant with detailed technical and cost breakdowns and interdependencies of key systems and subsystems. “The work done under LIFE was fantastic,” says Ma. “IPM lays out engineering and physics requirements for the entire system to test out different scenarios and see the impact. Now, we not only get to expand on all that but also leverage 15 years of new data from NIF, better codes, and high-performance computing (HPC), as well as new work in AI, ML, advanced manufacturing, diagnostics, and nonproliferation across the Laboratory.”

IPM describes an IFE power plant that requires a solid-state laser driver system to “pump” lasers with optical energy using laser diodes instead of flashlamps as at NIF. The plant will also need to fabricate and fill target capsules onsite and send them into its target chamber at a high enough frequency to produce baseload power. “We will have to repeatedly inject targets into the chamber, so the targets must be able to withstand and survive that process,” explains Ma. “Then, the lasers will track the moving targets, and when one gets to the center of the chamber, they would fire on the centered target, repeating 10 to 20 times per second.”

The facility would convert fusion energy into heat and then electricity via steam turbines, sending most of the electricity to the power grid and recycling the rest to power operations on subsequent shots. Neutrons from the reaction would produce tritium needed for the DT fuel by bombarding lithium isotopes in a “breeding blanket” material lining its target chamber. By closing both the power and fuel cycles, IFE plants are expected to be self-sustaining.

Thanks in part to IFE STARFIRE (IFE Science and Technology Accelerated Research for Fusion Innovation and Reactor Engineering), a Department of Energy (DOE)-funded multi-institutional IFE research and development hub, researchers across the Laboratory are working to meet the new system’s demands. IPM can help identify key challenges, test the viability of new designs, and direct future research. “Many technical models and cost models exist for IFE, but very few, if any, pair systems and cost models together at the same depth as IPM,” says Mackenzie Nelson, a technoeconomic systems analyst in the Computational Engineering Division. “This type of tool offers such an advantage because we can assess design choices from both a technical and economic standpoint and create blueprints for what an IFE plant could look like.”

(left to right) Livermore researchers Bassem El Dasher, Claudio Santiago, and Mackenzie Nelson discuss a 3D model of a proposed IFE power plant design alongside the Integrated Process Model (IPM). IPM has more than 270 potential user inputs that researchers and collaborators can use to assess different IFE design choices to see the technical and cost impact on the entire design.

Operational Demands

NIF’s target capsules are extremely precise, fragile, and can take weeks to fabricate, fill, and position. Researchers are trying to reconcile that factor with the estimated demand of more than 800,000 capsules per day produced at less than $0.50 each to achieve IFE plant viability. To do this, they are examining optimal target designs for IFE and exploring advanced manufacturing methods such as microfluidics, volumetric additive manufacturing, and two-photon polymerization. (See S&TR, April/May 2025 [archived PDF], pp. 16-19.) Additional projects involve developing diagnostic instruments that can collect, analyze, and combine data with other diagnostics at the 10 to 20 shot per second frequency and use it to improve lasers in real time.

Fusion energy systems such as IFE are also a regulatory challenge, as they generate high-energy neutrons capable of breeding plutonium or uranium-233 and rely on large quantities of tritium. “Pure fusion energy systems do not require fissile material, but there are still ways to misuse these technologies that pose proliferation risk,” says Yana Feldman, the associate program leader for international safeguards. Bad actors may only need small amounts of tritium to make nuclear weapons, and some breeding blanket designs may inadvertently produce traces of plutonium that may be diverted for military purposes.

Nuclear fission reactors are regulated through international agreements and export control rules, and the independent International Atomic Energy Agency (IAEA) verifies that nuclear material and facilities are only being used for peaceful purposes. Neither treaties nor the IAEA address fusion energy, and no consensus has been reached on whether fusion energy systems need an international verification program. Verification methods for safeguarding tritium are also far less developed than for plutonium and uranium and focus more on contamination and transfers than analytical accounting for discrepancies. The precise scale of allowable tritium unaccounted for without posing proliferation risk is also unclear.

Fusion systems can be designed for proliferation resistance, but not having an existing design remains a challenge.

International security analyst Anne-Marie Riitsaar and her colleagues are exploring these complexities and starting conversations with international fusion experts and private industry to raise awareness. Riitsaar also plans to collaborate with the IPM team to map tritium diversion vulnerabilities and identify high-risk points where researchers could incorporate surveillance methods into plant designs to detect and prevent potential misuse. “People sometimes ask me why I’m thinking about fusion energy regulations and proliferation risks at this point, but it’s not too early,” says Riitsaar. “Reaching a multinational consensus on regulating sensitive technologies takes considerable time and effort.”

The National Ignition Facility is an experimental facility and not a power plant, so a commercial IFE plant design has vastly different requirements—many of which are being studied by Livermore researchers and their collaborators.

NIFViable IFE plant (estimated)
Repetition rateOne shot per day10 to 20 shots per second
Energy gain4.13 times (as of April 2025)30 times (minimum), 50 times to 100 times (ideal)
How lasers gain energyFlashlampsDiode pumping
Target fabrication and fuel fillingFabricated offsite over several weeks and filled manually in 1 to 5 daysMass-manufactured and filled in a target factory within the facility
Target deliveryPositioned manually within the Target ChamberShot into the plant’s target chamber approximately 10 to 20 times per second
Laser alignmentComputationally in real time, taking up to 8 hoursIn real time
Power cycleOpen, requiring outside energy sourcesClosed, applying reused energy to power laser and ancillary plant operations
Fuel cycle (tritium)Produced offsiteBred onsite

The Laser Driven Fusion Integration Research and Science Test Facility (LD-FIRST) is a proposed blueprint for a proof-of-concept IFE facility that will test all the key IFE subsystems in an integrated fashion. A public-private partnership will likely be necessary to build the facility and will help the IFE community address the main subset of risks and the technological challenges of building a commercial plant.

Converging on a Solution

The team seeks to make IPM as accurate and comprehensive as possible by meeting with subject matter experts across the Laboratory to incorporate the latest research. “We’re trying to evolve the model so it has the same level of high detail across every single functional area to tell us where we can focus research and help us find optimized solutions that we could propose to industry,” says Nelson.

Computer scientist Claudio Santiago and his colleagues also modernized IPM by porting its framework from Microsoft Excel to Python in December 2024, making it compatible with AI, ML, design optimization, and HPC to further inform designs. “Once we think about all the forcing functions such as minimum shot yield and materials requirements pinning us in from every direction, we end up with an optimized solution space. As we sharpen the pencil more with these tools, that optimized solution box gets smaller until eventually we’ve converged on a point design,” says IFE lead systems engineer Justin Galbraith. Galbraith and his team’s point design is called the Laser Driven Fusion Integration Research and Science Test Facility, or LD-FIRST, a proof-of-concept physics demonstration facility for IFE. “That point design, we anticipate, will serve as the foundation for a future public-private partnership that would facilitate building and realizing a physical facility to focus the IFE community in pursuit of fusion power on the grid,” says Galbraith.

Livermore is leading the charge in IFE, helping the United States develop a technological roadmap, growing and coordinating science and technology efforts within the Laboratory, and fostering partnerships across the fusion industry, academia, and government.

Ma chaired DOE’s “Basic Research Needs for IFE” workshop and report in 2022 and co-chairs the subcommittee providing recommendations on the nation’s fusion activities through DOE’s Fusion Energy Sciences Advisory Committee. She and her team travel often to Washington, D.C., working with DOE and legislators to expand fusion energy research and advocacy in the nation. Livermore also leads a “Collaboratory” with other DOE national laboratories to connect research project leads and facilitate public-private partnerships. The Collaboratory has hosted multiple events with industry, and the Laboratory has partnered with three private companies who aim to design pilot IFE plants.

Meanwhile, Galbraith and other IFE leaders have served as technical advisors for engineering design teams at Texas A&M University and given them IFE-relevant problems to solve, including advanced chamber and blanket design. Galbraith is working with Nelson to develop the IFE plant design portion of a high-energy-density science summer school program, which Nelson is leading in 2025 at the University of California at San Diego, and they have developed IFE curriculum that has been deployed at six universities starting in spring 2025. “We’re hoping we can get a group of students really excited about fusion and start to build up the next generation of engineers and scientists that will make fusion a reality,” says Galbraith. The team has led IFE strategic planning exercises at the Laboratory, and Lawrence Livermore will stand up a new fusion institute—named “LIFT,” for Livermore Institute for Fusion Technology—a research and development center that will coordinate and centralize institutional fusion energy research.

Harnessing IFE will be a massive undertaking, but Livermore’s broad and deep expertise, facilities, and capabilities put the Laboratory in a unique position to lead and play an impactful role. “If we can set it up correctly, IFE will be a big piece of the Laboratory’s long-term vision,” says Ma. “IFE plays off of our history and all of our strengths, and it is critical for long-term national security.”

Education and Word and Number Hidden Vagueness

These mini-essays help students of any age to re-understand education in a deeper and more connected way.

They look for “circum-spective” intelligence. (Not in the sense of prudential or cautious but in the sense of “around-looking.”)

One of the things to begin to see is that explaining things in schools is misleading “ab initio” (i.e., from the beginning).

Let’s do an example:

In basic algebra, you’re asked: what happens to (x2 – 1)/(x – 1) as x “goes to” (i.e., becomes) 1.

If you look at the numerator (thing on top), x2 is also 1 (since 1 times 1 is 1) and (1 – 1) is zero. The denominator is also (1 – 1) and zero.

Thus you get 0 divided by 0.

You’re then told that’s a no-no and that’s because zeros and infinities lead to all kinds of arithmetic “bad behavior” or singularities.

You’re then supposed to see that x2 – 1 can be re-written as (x – 1)(x + 1) and since “like cancels like,” you cancel the x – 1 is the numerator and denominator and “get rid” of it.

This leaves simply x + 1. So, as x goes to 1, x + 1 goes to 2 and you have a “legitimate” answer and have bypassed the impasse of 0 acting badly (i.e., zero divided by zero).

If you re-understand all this more slowly you’ll see that there are endless potential confusions:

For example: you cannot say that (x2 – 1)/(x – 1) = x + 1 since looking at the two sides of the equal sign shows different expressions which are not equal.

They’re also not really equivalent.

You could say that coming up with x + 1 is a workaround or a “reduced form” or a “downstream rewrite” of (x2 – 1)/(x – 1).

This reminds us of the endless confusions in high school science: if you combine hydrogen gas (H2) with oxygen gas (O2) you don’t get water (H2O). Water is the result of a chemical reaction giving you a compound.

A mixture is not a compound. Chemistry is based on this distinction.

Math and science for that matter, are based on taking a formula or expression (like the one we saw above) and “de-cluttering” it or “shaking loose” a variant form which is not identical and not the same but functionally equivalent in a restricted way.

A lot of students who fail to follow high school or college science sense these and other “language and number” problems of hidden vagueness.
School courses punish students who “muse” to themselves about hidden vagueness. This behavior is pre-defined as “bad woolgathering” but we turn this upside down and claim it is potentially “good woolgathering” and might lead to enchantment which then underlies progress in getting past one’s fear of something like math or science or anything else.

One is surrounded by this layer of reality on all sides, what Wittgenstein calls “philosophy problems which are really language games.”

Think of daily life: you say to someone: “you can count one me.” You mean trust, rely on, depend on, where count on is a “set phrase.” (The origin of the phrase and how it became a set phrase is probably unknowable and lost in the mists of time.)

“You can count on me” does not mean you can stand on me and then count something…one, two, three.

In other words in all kinds of language (English, say, or math as a language) one is constantly “skating over” such logic-and-nuance-and-meaning issues.

The genius Kurt Gödel (Einstein’s walk around buddy at Princeton) saw this in a deep way and said that it’s deeply surprising that languages work at all (spoken, written or mathematical) since the bilateral sharing of these ambiguities would seem deadly to any clarity at all and communication itself would seem a rather unlikely outcome.

You could also say that drama giants of the twentieth century like Pinter, Ionesco and Beckett, intuit these difficulties which then underlie their plays.

All of this together gives you a more “composite” “circum-spective” view of what is really happening in knowledge acquisition.

Physics AI Predicts That Earth Goes Around the Sun

from Nature Briefing:

Hello Nature readers,

Today we learn that a computer Copernicus has rediscovered that Earth orbits the Sun, ponder the size of the proton and see a scientific glassblower at work.

Physicists have designed artificial intelligence that thinks like the astronomer Nicolaus Copernicus by realizing the Sun must be at the center of the Solar System. (NASA/JPL/SPL)

AI ‘Discovers’ That Earth Orbits the Sun [PDF]

A neural network that teaches itself the laws of physics could help to solve some of physics’ deepest questions. But first it has to start with the basics, just like the rest of us. The algorithm has worked out that it should place the Sun at the centre of the Solar System, based on how movements of the Sun and Mars appear from Earth.

The machine-learning system differs from others because it’s not a black that spits out a result based on reasoning that’s almost impossible to unpick. Instead, researchers designed a kind of ‘lobotomizedneural network that is split into two halves and joined by just a handful of connections. That forces the learning half to simplify its findings before handing them over to the half that makes and tests new predictions.

Next FDA Chief Will Face Ongoing Challenges

U.S. President Donald Trump has nominated radiation oncologist Stephen Hahn to lead the Food and Drug Administration (FDA). If the Senate confirms Hahn, who is the chief medical executive of the University of Texas MD Anderson Cancer Center, he’ll be leading the agency at the centre of a national debate over e-cigarettes, prompted by a mysterious vaping-related illness [archived PDF] that has made more than 2,000 people sick. A former FDA chief says Hahn’s biggest challenge will be navigating a regulatory agency under the Trump administration, which has pledged to roll back regulations.


Do We Know How Big a Proton Is?
[PDF]

A long-awaited experimental result has found the proton to be about 5% smaller than the previously accepted value. The finding seems to spell the end of the ‘proton radius puzzle’: the measurements disagreed if you probed the proton with ordinary hydrogen, or with exotic hydrogen built out of muons instead of electrons. But solving the mystery will be bittersweet: some scientists had hoped the difference might have indicated exciting new physics behind how electrons and muons behave.

Contingency Plans for Research After Brexit

The United Kingdom should boost funding for basic research and create an equivalent of the prestigious European Research Council (ERC) if it doesn’t remain part of the European Union’s flagship Horizon Europe research-funding program [archived PDF]. That’s the conclusion of an independent review of how UK science could adapt and collaborate internationally after Brexit — now scheduled for January 31, 2020.

Nature’s 150th anniversary

A Century and a Half of Research and Discovery

This week is a special one for all of us at Nature: it’s 150 years since our first issue, published in November 1869. We’ve been working for well over a year on the delights of our anniversary issue, which you can explore in full online.

10 Extraordinary Nature Papers

A series of in-depth articles from specialists in the relevant fields assesses the importance and lasting impact of 10 key papers from Nature’s archive. Among them, the structure of DNA, the discovery of the hole in the ozone layer above Antarctica, our first meeting with Australopithecus and this year’s Nobel-winning work detecting an exoplanet around a Sun-like star.

A Network of Science

The multidisciplinary scope of Nature is revealed by an analysis of more than 88,000 papers Nature has published since 1900, and their co-citations in other articles. Take a journey through a 3D network of Nature’s archive in an interactive graphic. Or, let us fly you through it in this spectacular 5-minute video.

Then dig deeper into what scientists learnt from analyzing tens of millions of scientific articles for this project.

150 Years of Nature, in Graphics

An analysis of the Nature archive reveals the rise of multi-author papers, the boom in biochemistry and cell biology, and the ebb and flow of physical chemistry since the journal’s first issue in 1869. The evolution in science is mirrored in the top keywords used in titles and abstracts: they were ‘aurora’, ‘Sun’, ‘meteor’, ‘water’ and ‘Earth’ in the 1870s, and ‘cell’, ‘quantum’, ‘DNA’, ‘protein’ and ‘receptor’ in the 2010s.

Evidence in Pursuit of Truth

A century and a half has seen momentous changes in science, and Nature has changed along with it in many ways, says an Editorial in the anniversary edition. But in other respects, Nature now is just the same as it was at the start: it will continue in its mission to stand up for research, serve the global research community and communicate the results of science around the world.

Features & Opinion

Nature covers: from paste-up to Photoshop

Nature creative director Kelly Krause takes you on a tour of the archive to enjoy some of the journal’s most iconic covers, each of which speaks to how science itself has evolved. Plus, she touches on those that didn’t quite hit the mark, such as an occasion of “Photoshop malfeasance” that led to Dolly the sheep sporting the wrong leg.

Podcast: Nature bigwigs spill the tea

In this anniversary edition of BackchatNature editor-in-chief Magdalena Skipper, chief magazine editor Helen Pearson and editorial vice president Ritu Dhand take a look back at how the journal has evolved over 150 years, and discuss the part that Nature can play in today’s society. The panel also pick a few of their favorite research papers that Nature has published, and think about where science might be headed in the next 150 years.

Where I Work

Scientific glassblower Terri Adams uses fire and heavy machinery to hand-craft delicate scientific glass apparatus. “My workbench hosts an array of tools for working with glass, many of which were custom-made for specific jobs,” says Adams. “Each tool reminds me of what I first used it for and makes me consider how I might use it again.” (Leonora Saunders for Nature)

Quote of the Day

“At the very least … we should probably consider no longer naming *new* species after awful humans.”

Scientists should stop naming animals after terrible people — and consider renaming the ones that already are, argues marine conservation biologist and science writer David Shiffman. (Scientific American)

Yesterday was Marie Skłodowska Curie’s birthday, and for the occasion, digital colorist Marina Amaral breathed new life into a photo of Curie in her laboratory

(If you have recommended people before and you want them to count, please ask them to email me with your details and I will make it happen!) Your feedback, as always, is very welcome at briefing@nature.com.

Flora Graham, senior editor, Nature Briefing