LIFE (“Laser Inertial Fusion Energy”) was a project run at Lawrence Livermore National Laboratory (LLNL) between 2008 and 2013 to design a fusion power plant based on the science experiment at NIF. Over $100M was directed over that period, with dozens of companies, national labs, and university partners working together on all aspects of the problem.

A prerequisite for LIFE to proceed was fusion ignition, but in 2013 when that had not yet been achieved, the LIFE project was ended. Our co-founder, Mike Dunne, led the LIFE project during his time at LLNL. We had to wait for the science to catch up (fortunately, this finally happened in 2022, thanks to our co-founder Annie Kritcher and the amazing team working on the NIF).

Components of Inertia (e.g. capabilities to commercialize fusion energy) build from this $100M, 5-year LIFE design study undertaken by LLNL and partners. LIFE was a self-consistent power plant design, but it was developed prior to the achievement of ignition and so made some assumptions that today we know are not valid. One example is the size of laser needed to robustly achieve ignition and fusion gain. So, at Inertia we’re making significant modifications to the physics design and laser driver required, building off of lessons learned and multi-year efforts at the NIF.

Inertia has updated the LIFE plan, based on over 10 years of additional learnings, improvements in the semiconductor laser diode and optics industries, and most importantly the achievement of fusion ignition at NIF. The Inertia design is based on the known performance characteristics of NIF ignition, gain and burn, coupled with data from multiple years of Diode-Pumped Solid-State Laser operation & development, and target manufacturing development.

Below are some of the major developments since the LIFE design that Inertia has incorporated to date:

Target Design

LIFE: Of necessity, since ignition hadn’t been achieved, LIFE used an indicative, uncalibrated design that was based on an early science campaign known as the National Ignition Campaign (NIC). This was unsuccessful since it relied on achieving ultra-high compression that was prone to instabilities, laser-plasma interactions and implosion symmetry issues that prohibited ignition.

Inertia: Our design is scaled from the demonstrated approach to ignition and gain on the NIF, benchmarked on full-scale simulations. Changes include differences in both the target materials and dimensions, and the way the laser is precisely delivered to the target. Further improvements to the target design (for example the ratio of fuel to capsule mass and its symmetry) enable higher gains within a tested physics space. On top of all this, Inertia is building a laser about 4 times the size of NIF to account for any imperfections in the mass-manufactured targets needed for fusion energy. This extra laser energy allows a larger target to be used, at a scale beyond where hydrodynamic instabilities and symmetry issues could limit ignition and burn for mass-manufactured targets.

Commentary: Inertia's design is benchmarked on NIF, extended to IFE-specific performance using the design codes - and design team - that achieved ignition and gain.

Laser Energy

LIFE: 2.2 to 3 MJ

Inertia: 10 MJ

Commentary: Inertia's laser energy is set using knowledge of the ignition point and gain scaling. Substantial margin has been added to allow robust, high confidence performance to degradation and subsequent optimization. These degradations include hydrodynamic instabilities seeded by at-cost target components, asymmetries from precision high-rep rate fielding, and laser-plasma interactions at longer scale-length.

Laser Architecture

LIFE: 384 beamlines, 2011-era "CELL" design, untested.

Inertia: 1000 beamlines

Commentary: Inertia’s laser is based on experience from an interior fusion energy (IFE) prototype laser called the High-Repetition-Rate Advanced Petawatt Laser System (HAPLS) that was built by LLNL. Inertia's laser design is informed by the as-built performance of HAPLS that used the proposed LIFE architecture - taking the elements that worked, removing those that were problematic - and extending to the use of present-day diode/optics performance. Inertia has a much higher number of smaller-aperture beams to allow commercial optics to be used, and to enable solutions for key components (e.g., for frequency-conversion). This also helps with maintaining very high availability in the power plant - with more beamlines, a number of individual unit cells can be offline at any point in time for maintenance without impacting plant operation. More beamlines also make controlling the implosion drive symmetry easier.

Tritium Breeding Material‍

LIFE: Liquid lithium metal

Inertia: Lithium-based ternary alloy

Commentary: Use of a pure lithium metal with LIFE introduced complex safety problems.

Inertia is mitigating these through the use of a low-reactivity alloy, informed by detailed modeling, AI/ML materials optimization, and direct testing.