A shortage of tritium fuel may leave fusion energy with an empty tank (Fusion Reactors)

Out of gas
A shortage of tritium fuel may leave fusion energy with an empty tank

   23 Jun 20221:00 PM ET By Daniel Clery

------------

In 2020, Canadian Nuclear Laboratories delivered five steel drums, lined with cork to absorb shocks, to the Joint European Torus (JET), a large fusion reactor in the United Kingdom. Inside each drum was a steel cylinder the size of a Coke can, holding a wisp of hydrogen gas—just 10 grams of it, or the weight of a couple sheets of paper.

This wasn’t ordinary hydrogen but its rare radioactive isotope tritium, in which two neutrons and a proton cling together in the nucleus. At $30,000 per gram, it’s almost as precious as a diamond, but for fusion researchers the price is worth paying. When tritium is combined at high temperatures with its sibling deuterium, the two gases can burn like the Sun. The reaction could provide abundant clean energy—just as soon as fusion scientists figure out how to efficiently spark it.

Last year, the Canadian tritium fueled an experiment at JET showing fusion research is approaching an important threshold: producing more energy than goes into the reactions. By getting to one-third of this breakeven point, JET offered reassurance that ITER, a similar reactor twice the size of JET under construction in France, will bust past breakeven when it begins deuterium and tritium (D-T) burns sometime next decade. “What we found matches predictions,” says Fernanda Rimini, JET’s plasma operations expert.

But that achievement could be a Pyrrhic victory, fusion scientists are realizing. ITER is expected to consume most of the world’s tritium, leaving little for reactors that come after.

Fusion advocates often boast that the fuel for their reactors will be cheap and plentiful. That is certainly true for deuterium: Roughly one in every 5000 hydrogen atoms in the oceans is deuterium, and it sells for about $13 per gram. But tritium, with a half-life of 12.3 years, exists naturally only in trace amounts in the upper atmosphere, the product of cosmic ray bombardment. Nuclear reactors also produce tiny amounts, but few harvest it.

Most fusion scientists shrug off the problem, arguing that future reactors can breed the tritium they need. The high-energy neutrons released in fusion reactions can split lithium into helium and tritium if the reactor wall is lined with the metal. Despite demand for it in electric car batteries, lithium is relatively plentiful.


But there’s a catch: In order to breed tritium you need a working fusion reactor, and there may not be enough tritium to jump-start the first generation of power plants. The world’s only commercial sources are the 19 Canada Deuterium Uranium (CANDU) nuclear reactors, which each produce about 0.5 kilograms a year as a waste product, and half are due to retire this decade. The available tritium stockpile—thought to be about 25 kilograms today—will peak before the end of the decade and begin a steady decline as it is sold off and decays, according to projections in ITER’s 2018 research plan.
The dwindling tritium supply

The few kilograms of commercially available tritium come from CANDU plants, a type of nuclear reactor in Canada and South Korea. According to ITER projections, supplies will peak this decade, then begin a steady decline that will accelerate when ITER begins burning tritium.

Graph of projected tritium supplies from 2000 to 2060. Supplies peak around 28kg before 2030. Decline accelerates in late 2030s as ITER burns 0.9 kg of tritium per year, dropping to under 5 kg by 2050. Even without ITER,supplies would decline because of CANDU retirement, tritium decay, and other sales. In early 2050s, inventory is boosted by about 1 kg as decommissioned ITER returns unused tritium.

Graphic: K. Franklin/Science; (Data) ITER Research Plan within the Staged Approach, ITR-18-003, (2018)

ITER’s first experiments will use hydrogen and deuterium and produce no net energy. But once it begins energy-producing D-T shots, Alberto Loarte, head of ITER’s science division, expects the reactor to eat up to 1 kilogram of tritium annually. “It will consume a significant amount of what is available,” he says. Fusion scientists wishing to fire up reactors after that may find that ITER already drank their milkshake.

To compound the problem, some believe tritium breeding—which has never been tested in a fusion reactor—may not be up to the task. In a recent simulation, nuclear engineer Mohamed Abdou of the University of California, Los Angeles, and his colleagues found that in a best-case scenario, a power-producing reactor could only produce slightly more tritium than it needs to fuel itself. Tritium leakages or prolonged maintenance shutdowns will eat away at that narrow margin.

Scarce tritium is not the only challenge fusion faces; the field must also learn to deal with fitful operations, turbulent bursts of plasma, and neutron damage (see sidebar, below). But for Daniel Jassby, a plasma physicist retired from Princeton Plasma Physics Laboratory (PPPL) and a known critic of D-T fusion energy, the tritium issue looms large. It could be fatal for the entire enterprise, he says. “This makes deuterium-tritium fusion reactors impossible.”

If not for CANDU reactors, D-T fusion would be an unattainable dream. “The luckiest thing to happen for fusion in the world is that CANDU reactors produce tritium as a byproduct,” Abdou says. Many nuclear reactors use ordinary water to cool the core and “moderate” the chain reaction, slowing neutrons so they are more likely to trigger fission. CANDU reactors use heavy water, in which deuterium takes the place of hydrogen, because it absorbs fewer neutrons, leaving more for fission. But occasionally, a deuterium nucleus does capture a neutron and is transformed into tritium.

If too much tritium builds up in the heavy water it can be a radiation hazard, so every so often operators send their heavy water to the utility company Ontario Power Generation (OPG) to be “detritiated.” OPG filters out the tritium and sells off about 100 grams of it a year, mostly as a medical radioisotope and for glow-in-the-dark watch dials and emergency signage. “It’s a really nice waste-to-product story,” says Ian Castillo of Canadian Nuclear Laboratories, which acts as OPG’s distributor.

Fusion reactors will add significantly to the demand. OPG Vice President Jason Van Wart expects to be shipping up to 2 kilograms annually beginning in the 2030s, when ITER and other fusion startups plan to begin burning tritium. “Our position is to extract all we can,” he says.

But the supply will decline as the CANDUs, many of them 50 years old or more, are retired. Researchers realized more than 20 years ago that fusion’s “tritium window” would eventually slam shut, and things have only got worse since then. ITER was originally meant to fire up in the early 2010s and burn D-T that same decade. But ITER’s start has been pushed back to 2025 and could slip again because of the pandemic and safety checks demanded by French nuclear regulators. ITER won’t burn D-T until 2035 at the earliest, when the tritium supply will have shriveled.

Once ITER finishes work in the 2050s, 5 kilograms or less of tritium will remain, according to the ITER projections. In a worst-case scenario, “it would appear that there is insufficient tritium to satisfy the fusion demand after ITER,” concedes Gianfranco Federici, head of fusion technology at the EuroFusion research agency.
A segment of a huge donut-shaped reactor vessel, suspended in a circular room.
In May, engineers began to assemble ITER’s reactor vessel. The first tritium burns are scheduled for 2035. ITER Organization

Some private companies are designing smaller fusion reactors that would be cheaper to build and—initially at least—use less tritium. Commonwealth Fusion Systems, a startup in Massachusetts, says it has already secured tritium supplies for its compact prototype and early demonstration reactors, which are expected to need less than 1 kilogram of the isotope during development.

But larger, publicly funded test reactors planned by China, South Korea, and the United States could need several kilograms each. Even more will be needed to start up EuroFusion’s planned successor to ITER, a monster of a machine called DEMO. Meant to be a working power plant, it is expected to be up to 50% larger than ITER, supplying 500 megawatts of electricity to the grid.

Fusion reactors generally need a large startup tritium supply because the right conditions for fusion only occur in the hottest part of the plasma of ionized gases. That means very little of the tritium in the doughnut-shaped reactor vessel, or tokamak, gets burned. Researchers expect ITER to burn less than 1% of the injected tritium; the rest will diffuse out to the edge of the tokamak and be swept into a recycling system, which removes helium and other impurities from the exhaust gas, leaving a mix of D-T. The isotopes are then separated and fed back into the reactor. This can take anywhere from hours to days.

DEMO’s designers are working on ways to reduce its startup needs. “We need to have a low tritium [starting] inventory,” says Christian Day of the Karlsruhe Institute of Technology, project leader in the design of DEMO’s fuel cycle. “If you need 20 kilograms to fill it, that’s a problem.”

One way to tame the demand is to fire frozen fuel pellets deeper into the reactor’s burning zone, where they will burn more efficiently. Another is to cut recycling time to just 20 minutes, by using metal foils as filters to strip out impurities quickly, and also by feeding the hydrogen isotopes straight back into the machine without separating them. It may not be a perfect 50-50 D-T mix, but for a working reactor it will be close enough, Day says.

But Abdou says DEMO’s appetite is still likely to be large. He and his colleagues modeled the D-T fuel cycle for power-producing reactors, including DEMO and its successors. They estimated factors, including the efficiency of burning D-T fuel, the time it takes to recycle unburnt fuel, and the fraction of time the reactor will operate. In a paper published in 2021 in Nuclear Fusion, the team concludes that DEMO alone will require between 5 kilograms and 14 kilograms of tritium to begin—more than is likely to be available when the reactor is expected to fire up in the 2050s.

Even if the DEMO team and other post-ITER reactor designers can cut their tritium needs, fusion will have no future if tritium breeding doesn’t work. According to Abdou, a commercial fusion plant producing 3 gigawatts of electricity will burn 167 kilograms of tritium per year—the output of hundreds of CANDU reactors.

The challenge for breeding is that fusion doesn’t produce enough neutrons, unlike fission, where the chain reaction releases an exponentially growing number. With fusion, each D-T reaction only produces a single neutron, which can breed a single tritium nucleus. Because breeding systems can’t catch all these neutrons, they need help from a neutron multiplier, a material that, when struck by a neutron, gives out two in return. Engineers plan to mix lithium with multiplier materials such as beryllium or lead in blankets that line the walls of the reactors.

ITER will be the first fusion reactor to experiment with breeding blankets. Tests will include liquid blankets (molten mixtures of lithium and lead) as well as solid “pebble beds” (ceramic balls containing lithium mixed with balls of beryllium). Because of cost cuts, ITER’s breeder systems will line just 4 square meters of the 600-square-meter reactor interior. Fusion reactors after ITER will need to cover as much of the surface as they possibly can to have any chance of satisfying their tritium needs.

The tritium can be extracted continuously or during scheduled shutdowns, depending on whether the lithium is in liquid or solid form, but the breeding must be relentless. The breeding blankets also have a second job: absorbing gigawatts of power from the neutrons and turning it into heat. Pipes carrying water or pressurized helium through the hot blankets will pick up the heat and produce steam that drives electricity-producing turbines. “All of this inside the environment of a fusion reactor with its ultrahigh vacuum, neutron bombardment, and high magnetic field,” says Mario Merola, head of engineering design at ITER. “It’s an engineering challenge.”

For Abdou and his colleagues, it is more than a challenge—it may well be an impossibility. Their analysis found that with current technology, largely defined by ITER, breeding blankets could, at best, produce 15% more tritium than a reactor consumes. But the study concluded the figure is more likely to be 5%—a worrisomely small margin.

One critical factor the authors identified is reactor downtime, when tritium breeding stops but the isotope continues to decay. Sustainability can only be guaranteed if the reactor runs more than 50% of the time, a virtual impossibility for an experimental reactor like ITER and difficult for prototypes such as DEMO that require downtime for tweaks to optimize performance. If existing tokamaks are any guide, Abdou says, time between failures is likely to be hours or days, and repairs will take months. He says future reactors could struggle to run more than 5% of the time.

To make breeding sustainable, operators will also need to control tritium leaks. For Jassby, this is the real killer. Tritium is notorious for permeating the metal walls of a reactor and escaping through tiny gaps. Abdou’s analysis assumed a loss rate of 0.1%. “I don’t think that’s realistic,” Jassby says. “Think of all the places tritium has to go” as it moves through the complex reactor and reprocessing system. “You can’t afford to lose any tritium.”

Two private fusion efforts have decided to simply forgo tritium fuel. TAE Technologies, a California startup, plans to use plain hydrogen and boron, whereas Washington state startup Helion will fuse deuterium and helium-3, a rare helium isotope. These reactions require higher temperatures than D-T, but the companies think that’s a price worth paying to avoid tritium hassles. “Our company’s existence owes itself to the fact that tritium is scarce and a nuisance,” says TAE CEO Michl Binderbauer.

The alternative fusion reactions have the added appeal of producing fewer or even no neutrons, which avoids the material damage and radioactivity that the D-T approach threatens. Binderbauer says the absence of neutrons should allow TAE’s reactors—which stabilize spinning rings of plasma with particle beams—to last 40 years. The challenge is temperature: Whereas D-T will fuse at 150 million degrees Celsius, hydrogen and boron require 1 billion degrees.

Helion’s fuel of deuterium and helium-3 burns at just 200 million degrees, achieved using plasma rings similar to TAE’s but compressed with magnetic fields. But helium-3, although stable, is nearly as rare and hard to acquire as tritium. Most commercial sources of it depend on the decay of tritium, typically from military stockpiles. Helion CEO David Kirtley says, however, that by putting extra deuterium in the fuel mix, his team can generate D-D fusion reactions that breed helium-3. “It’s a much lower cost system, easier to fuel, easier to operate,” he says.

Still, advocates of conventional D-T fusion believe tritium supplies could be expanded by building more fission reactors. Militaries around the world use tritium to boost the yield of nuclear weapons, and have built up their own tritium stockpiles using purpose-built or adapted commercial nuclear reactors.

The U.S. Department of Energy (DOE), for example, relies on commercial reactors—Watts Bar Units 1 and 2, operated by the Tennessee Valley Authority—in which lithium control rods have replaced some of the boron ones. The rods are occasionally removed and processed to extract tritium. DOE supplied PPPL with tritium in the 1980s and ’90s when the lab had a D-T burning reactor. But Federici doesn’t think the agency, or militaries around the world, will get into the business of selling the isotope. “Defense stockpiles of tritium are unlikely ever to be shared,” he says.

Perhaps the world could see a renaissance of the CANDU technology. South Korea has four CANDU reactors and a plant for extracting tritium but does not sell it commercially. Romania has two and is working on a tritium facility. China has a couple of CANDUs and India has built a handful of CANDU derivatives. Their tritium production could be turbocharged by adding lithium rods to their cores or doping the heavy water moderator with lithium. But a 2018 paper in Nuclear Fusion by Michael Kovari of the Culham Centre for Fusion Energy and colleagues argues such modifications would likely face regulatory barriers because they could compromise reactor safety and because of the dangers of tritium itself.

Some say fusion reactors could create their own startup tritium by running on deuterium alone. But D-D reactions are wildly inefficient at tokamak temperatures and instead of producing energy would consume huge amounts of electricity. According to Kovari’s study, D-D tritium breeding might cost $2 billion per kilogram produced. All such solutions “pose significant economic and regulatory difficulties,” Kovari says.

More at link:  https://www.science.org/content/article/fusion-power-may-run-fuel-even-gets-started

These reactors need a lot of "geometry" for shooting intense lasers in a gold plated "cage" that allows for "fusion" with doped salt layers.
-------------------
https://lasers.llnl.gov/news/nature-physics-paper-describes-burning-plasma-target-laser-designs

https://www.ans.org/news/article-3613/burning-plasma-state-achieved-at-lawrence-livermore-lab/

Nuclear fusion, which mimics the energy-generating method of the Sun and the stars, has the potential to provide practically limitless clean energy.

Now, a new analysis of the plasma, published in a paper in the journal Nature Physics, reveals surprising new details that could help the scientific community finally achieve the holy grail of nuclear fusion — net energy production.
Analyzing the NIF's world's first burning plasma

Since 2009, NIF scientists have been using an array of 192 lasers to shoot high-energy pulses at a small fuel capsule made up of deuterium and tritium. The researchers apply the destructive, intense heat of the lasers to cause the atoms to fuse into helium and release massive amounts of energy.
------------------
Limitless nuclear fusion energy is one step closer thanks to burning plasma experiment
We could be a step closer to the commercially viable production of limitless nuclear fusion energy.
Chris Young
Published: Nov 15, 2022 09:02 AM EST
https://interestingengineering.com/science/limitless-nuclear-fusion-energy-is-one-step-closer-thanks-to-burning-plasma-experiment
https://www.nature.com/articles/s41567-021-01485-9

One of the last remaining milestones in fusion research before attaining ignition and self-sustaining energy production is creating a burning plasma, where the fusion reactions themselves are the primary source of heating in the plasma. A paper published in the journal Nature on January 26 describes recent experiments at Lawrence Livermore National Laboratory’s National Ignition Facility (NIF) that have achieved a burning plasma state.

“In these experiments, we achieved, for the first time in any fusion research facility, a burning plasma state where more fusion energy is emitted from the fuel than was required to initiate the fusion reactions, or the amount of work done on the fuel,” said LLNL physicist Annie Kritcher, who, with Chris Young, served as one of the lead authors of the Nature paper, “Design of inertial fusion implosions reaching the burning plasma regime.”

The work described in the paper was also the basis for the August 2021 NIF experiment that achieved 1.35 megajoules in the laboratory for the first time. According to LLNL, this accomplishment also validates the work done decades ago to establish the power and energy specifications for NIF.

Scaling up: The work outlined in the paper presents the inertial confinement fusion designs that enabled the achievement of laboratory burning plasma by developing more efficient ways to drive larger-scale fusion targets to the same extreme conditions required for significant fusion to occur, and within the current experimental confines of NIF. By increasing the scale while maintaining high levels of plasma pressure, the team was able to ultimately deliver more of the initial laser energy directly to the fusion plasma and jump-start the burn process. In doing so, the team found novel ways to control the implosion symmetry (by transferring energy between laser beams in a new way and by changing the target geometry). The designs were generated and optimized using a combination of theory, computational modeling (HYDRA), and semi-empirical models informed by experimental data.

“We learned where we could and could not trust the modeling and when to rely on semi-empirical models,” Kritcher said. “We also found that keeping the driver pressure up longer (i.e., a longer laser pulse) relative to the time it takes the target to ‘implode’ was important for maintaining a high plasma pressure. Without this pressure, and enough energy coupled to the hot dense plasma, we would not reach the extreme conditions required for significant fusion.”

Future work: “There is much work yet to be done, and this is a very exciting time for fusion research,” Kritcher said. “Following this work, the team further improved hohlraum efficiency in both platforms, increasing hot spot pressure which resulted in higher performance and the record 1.35 MJ HYBRID-E experiment.”

Kritcher said that this new platform is now the “basecamp” for a significant fraction of ongoing programmatic work, focusing on understanding the sensitivity of this new regime, improving the robustness of the platform, and further increasing the energy and pressure of the fusion hot spot. “This will be explored through a variety of ideas to increase fuel compression and energy coupling,” she said.

Nature also featured a paper titled “Burning plasma achieved in inertial fusion,” with LLNL physicists Alex Zylstra and Omar Hurricane serving as the lead authors.

---------
The use of deuterium-deuterium reactions to aid tritium breeding in tokamak fusion reactors

N. Mitchell1 and E. Salpietro1

Published under licence by IOP Publishing Ltd
Nuclear Fusion, Volume 26, Number 9 Citation N. Mitchell and E. Salpietro 1986 Nucl. Fusion 26 1246 DOI 10.1088/0029-5515/26/9/007

Abstract

Current designs for tokamak based fusion reactors usually consider deuterium-tritium reactions with a 50–50% mixture of D-T, to give a maximum power density, although design studies for pure D-D, He3-catalysed and T-catalysed tokamak fusion reactors have been performed. The letter considers a reactor burning a D-T mixture with an enhanced percentage of deuterium to increase the possibility of D-D reactions (a so-called T-catalysed D reactor). Most of the energy needed to maintain the burning plasma comes from D-T reactions, but the D-D reaction results in the generation of extra neutrons (or equally useful tritons or 3He nuclei), which can contribute to the overall neutron economy of the reactor. – A simple plasma energy balance for an ignited tokamak is used to study the usefulness of D-D reactions, with confinement times, safety factors, and beta limits as predicted by existing experimental devices. The authors consider both the improvements necessary in present plasma performance limits to produce useful D-D reaction rates as well as the effect of a lower plasma energy density on reactor size. – The object of the study has not been to consider the economics of such types of reactor, but rather to assess the potential of the D-D reaction to introduce some flexibility into a fusion reactor design. It is evident from design studies on next generation tokamaks that the overall neutron economy will be a major challenge in a fusion reactor and that the reduction of the necessary blanket breeding ratio could improve the feasibility of the overall design.

https://iopscience.iop.org/article/10.1088/0029-5515/26/9/007
https://iopscience.iop.org/article/10.1088/0029-5515/26/9/007/pdf

Vid on JET's Fusion Reactors:

Microsoft now has a ML library "DeepSpeed" for Fusion and molecular dynamics-"quantum" research:

What is DeepSpeed4Science?

Mission Statement
In the next decade, deep learning may revolutionize the natural sciences, enhancing our capacity to model and predict natural occurrences. This could herald a new era of scientific exploration, bringing significant advancements across sectors from drug development to renewable energy. In line with Microsoft’s mission to solve humanity’s most pressing challenges, the DeepSpeed team at Microsoft is responding to this opportunity by launching a new initiative called DeepSpeed4Science, aiming to build unique capabilities through AI system technology innovations to help domain experts unlock today’s biggest science mysteries.

Methodology
The DeepSpeed system is an industry leading open-source AI system framework, developed by Microsoft, that enables unprecedented scale and speed for deep learning training and inference on a wide range of AI hardware. By leveraging DeepSpeed’s current technology pillars (training, inference and compression) as base technology enablers, DeepSpeed4Science will create a new set of AI system technologies tailored for accelerating scientific discoveries by addressing their unique complexity beyond the common technical approaches used for accelerating generic large language models (LLMs). We work closely with internal and external partners who own AI-driven science models that represent key science missions, to identify and address general domain-specific AI system challenges. This includes climate science, drug design, biological understanding, molecular dynamics simulation, cancer diagnosis and surveillance, catalyst/material discovery, quantum computing, and other domains.

Ultimate Goals
• A new a platform and a unified repository for advanced AI system technologies for scientific discoveries.

• Open-source training/inference software system support tailored for science domains.

• Target important scientific domains and their most general/critical AI system challenges.

• It is designed to be inclusive, echoing Microsoft’s AI for Good commitment.

https://deepspeed4science.ai/

Chemical Research molecular dynamics:


Fusion Research:


Looks like they are wanting to play a role in molecular research:
----------

AI Powered Ab Initio Molecular Dynamics (AI2MD), MSR AI4Science

Figure 4:This animated figure illustrates one million steps of a molecular dynamics simulation, e.g., RBD-protein interacts with protein inhibitor. Simulations like this are efficient enough to generate trajectories long enough to observe chemically significant events.
Figure 4: One million steps of molecular dynamics simulation: RBD-protein interacts with protein inhibitor.

This project simulates the dynamics of large (million-atom) molecular systems with near ab initio accuracy using AI-powered force field models while maintaining the efficiency and scalability of classical molecular dynamics. The simulations are efficient enough to generate trajectories long enough to observe chemically significant events. Typically, millions or even billions of inference steps are required for this process. This poses a significant challenge in optimizing the inference speed of graph neural network (GNN)+ LLM models, for which DeepSpeed4Science will provide new acceleration strategies.

https://www.microsoft.com/en-us/research/blog/announcing-the-deepspeed4science-initiative-enabling-large-scale-scientific-discovery-through-sophisticated-ai-system-technologies/

Miles gives some background on density theory in this paper: http://milesmathis.com/pilot.pdf

Miles Mathis wrote:If we go back before Bohm, we find that other top physicists also disagreed with Born and the Born
rule. Schrodinger never agreed with Born's explanation of equilibrium, and neither did Einstein or
Planck. None of them ever agreed with the Born rule, pointing out that it was never a rule, but only a
bad guess. Karl Popper, the top physical philosopher at the time, also came down on the side of
Einstein and Schrodinger and Planck.

Given what we now know about the charge field, what can we say about equilibrium and the Born
rule? Well, since I have shown that Bohr made a basic error in his math, conflating the momentum of
the electron with that of the photon, we know the wavefunction actually applies to the photon. For this
reason alone, the Born rule totally evaporates. Since Born applied the probability density function to
the probability of finding a particle in a certain place, we cannot give the place to the electron and the
wavefunction to the photon. If the wavefunction goes to the photon, the probability has to go with the
photon also. Even if Born were correct about the number equality, the density function would have to
be telling us the probability of finding the photon in that place, not the electron.

---------
AI2BMD: efficient characterization of protein dynamics with ab initio accuracy

| July 2023


Biomolecular dynamics simulation is a fundamental technology for life sciences research, and its usefulness depends on its accuracy and efficiency. Classical molecular dynamics simulation is fast but lacks chemical accuracy. Quantum chemistry methods like density functional theory (DFT) can reach chemical accuracy but cannot scale to support large biomolecules. We introduce an AI-based ab initio biomolecular dynamics system (AI2BMD) that can efficiently simulate large biomolecules with ab initio accuracy. AI2BMD uses a protein fragmentation scheme and machine learning force field to achieve generalizable ab initio accuracy for energy and force calculations for various proteins comprising over 10,000 atoms. Compared to DFT, it reduces computational time by several orders of magnitude. With several hundred nanoseconds of dynamics simulations, AI2BMD demonstrated its capability of efficiently exploring the conformational space of peptides and proteins, deriving accurate 3J-couplings that match NMR experiments, and showing protein folding and unfolding tendencies. Furthermore, AI2BMD enables precise free energy calculations for protein folding, and the estimated melting temperatures are well aligned with experiments. AI2BMD could potentially complement wet-lab experiments, detect the dynamic processes of bioactivities, and enable biomedical research that is currently impossible to conduct.

https://www.microsoft.com/en-us/research/publication/ai2bmd-efficient-characterization-of-protein-dynamics-with-ab-initio-accuracy/