Better Accelerators to Produce Kilograms of Isotopes for Fast Space Propulsion

There is technology being perfected to make particle accelerators 100-1000 times lower cost. This would enable production of nuclear material for space propulsion that could reach up to 0.5% of light speed or more.

Scientists at DESY now report some of the first signs that PWA (Plasma Wakefield Accelerators) is ready to compete with traditional accelerators at low energies. PWA has the potential to radically miniaturise particle accelerators. Plasma waves are generated when a laser pulse or particle beam ploughs through a millimetres-long hydrogen-filled capillary, displacing electrons and creating a wake of alternating positive and negative charge regions behind it. The process is akin to flotsam and jetsam being accelerated in the wake of a speedboat, and the plasma “wakefields” can be thousands of times stronger than the electric fields in conventional accelerators, allowing particles to gain hundreds of MeV in just a few millimetres. But beam quality and intensity are significant challenges in such narrow confines.

A team from the LUX experiment at DESY and the University of Hamburg demonstrated, for the first time, a two-stage correction system to dramatically reduce the energy spread of accelerated electron beams. The first stage stretches the longitudinal extent of the beam from a few femtoseconds to several picoseconds using a series of four zigzagging bending magnets called a magnetic chicane. Next, a radio-frequency cavity reduces the energy variation to below 0.1%, bringing the beam quality in line with conventional accelerators.

Producing high-quality beams is only half the battle. To make laser-driven PWA a practical proposition, bunches must be accelerated not just once a second, like at LUX, but hundreds or thousands of times per second. This has now been demonstrated by KALDERA, DESY’s new high-power laser system.

With the exception of CERN’s AWAKE experiment (CERN Courier May/June 2024 p25), almost all plasma-wakefield accelerators are designed with medical or industrial applications in mind. Medical applications are particularly promising as they require lower beam energies and place less demanding constraints on beam quality.

AWAKE technology promises to bridge the gap between global developments at small scales and possible future electron–positron colliders. The first phase was completed in 2022. The results prove that wakefields driven by a full proton bunch can have a reproducible and tunable timing. This is not at all a trivial demonstration given that the experiment is based on an instability.

The third and final experimental milestone for Run 2 will then be to replace the 10 m-long accelerator plasma with a longer source and achieve proportionally larger energy gains. The AWAKE acceleration concept will then essentially be mature to propose particle-physics experiments, for example with bunches of a billion or so 50 GeV electrons.

The AWAKE collaboration at CERN has published a comprehensive recent roadmap and project update in 2025, showing a clear plan to demonstrate externally injected electron bunch acceleration to multi-GeV energies by 2031 with a scalable plasma acceleration technology. This includes developments of scalable plasma sources up to tens of meters, and efforts to maintain beam quality suitable for particle physics applications.

Starting after CERN’s Long Shutdown 3 (LS3), in a first phase of approximately two years, energy gain and bunch quality (charge, emittance, energy and relative energy spread) will be optimized both with RIF and electron bunch seeding in the self-modulator. These experiments will be performed with a 10 m-long accelerator plasma in a laser-ionized rubidium vapor source following the self-modulator plasma.

In the second phase, the following two years (∼2032-2033), the second plasma source will be replaced by a scalable discharge or helicon source, probably 20 m long, to demonstrate the scalability in length of the source, and of the energy gain, still with an accelerated bunch of good quality. Much larger energy gains (50 to 200 GeV) should then be possible by ”simply” increasing the length of the accelerator source.

Advanced accelerator technologies lowering the cost of accelerators for specific applications like TFINER isotope production—which involves large-scale isotope production of californium-254 or uranium-232 for space propulsion.

Lowering costs for isotope production in quantities of kilograms through plasma accelerators would depend on achieving:

High repetition rate, continuous operation

Robust, industrial-scale plasma sources

Reliable beam quality and control for isotope production efficiency

Energy efficiencies to reduce operational costs

While current 2025 roadmaps like AWAKE’s focus on particle physics applications, the technology’s scalable and compact nature strongly supports the prospect that improved plasma or laser wakefield accelerators could substantially lower the cost and footprint of accelerators needed for large-scale, specialized isotope production by 2030.

At Lawrence Berkeley National Laboratory, researchers demonstrated enhanced production of nuclear isomer populations using ultrafast electron beams from laser-plasma accelerators. This method holds promise for producing specific isotopes such as plutonium-238 (a vital spacecraft power source) by inducing decay of isotopes like americium-242m.

Emerging accelerator technologies could significantly reduce costs for producing TFINER isotopes (including baselines and alternatives like U-232) by enabling compact, efficient, and multi-isotope production. Traditional methods rely on large reactors (e.g., HFIR, $50-100M/year operations) or linacs, but new approaches focus on compactness, higher yields, and lower energy use.

Key developments as of 2024-2025

Plasma Wakefield Accelerators (PWFA/LWFA): Laser-driven plasma accelerators create GV/m fields in cm-scale plasmas, accelerating electrons/protons ~100-1,000x faster than conventional RF accelerators, potentially shrinking facility size/cost by 10-100x.

Compact (tabletop-scale) systems could cut build costs from $500M-$2B (traditional linac) to $10-100M, with 10 Hz repetition for high yields. 2024 advancements include Bayesian-optimized LWFA for stable beams, targeting isotope production.

Nusano’s Custom Klystron/Modulator Systems: Achieved milestone in 2024 for simultaneous production of up to 12 isotopes (e.g., medical + TFINER-relevant like Ac-227) in one run, using fast-pulsing linacs. Reduces costs by ~30-50% via efficiency and multiplexing.

SHINE/Phoenix Neutron Generators: Advanced compact accelerators for Mo-99 (fission-based), extendable to actinides. Low-energy cyclotrons/linacs cut costs vs. reactors.

These technologies could make kg-scale production feasible at $100-500M total (vs. billions), especially for U-232 or baselines, by 2030-2035. More traditional dedicated accelerators would be in the $6b-20Billion range to produce the 30 kilogram quantities of isotopes needed for TFINER nuclear propulsion.

Isotope Production

In 2025, the best isotope production facilities for medical and industrial purposes primarily rely on nuclear reactors and conventional particle accelerators (e.g., cyclotrons or linear accelerators), with limited scalability for heavy, transuranic isotopes like those needed for TFINER.

The High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory (ORNL) in the U.S. remains a top producer for neutron-irradiated isotopes, including transuranics like Cm-244 and Cf-252/254, with annual outputs in the gram range for medical/industrial needs.

Russia’s Obninsk facility (operational since early 2025) produces iodine-131 and samarium-153, while legacy sites like Savannah River have historically yielded ~6 kg of Cm-244 but are decommissioned, limiting supply.

Nusano’s West Valley City plant (Accelerator-Based opened in 2025) uses a proprietary linear accelerator to produce current good manufacturing practice (cGMP)-grade radioisotopes like lutetium-177 and actinium-225 for medical use, with capacities exceeding 40 isotopes.

The Facility for Rare Isotope Beams (FRIB) at Michigan State University, fully operational in 2025, employs heavy-ion acceleration for rare isotopes, including potential transuranics.

SHINE Technologies’ Wisconsin facility scales Mo-99 production via accelerator-driven neutron sources, while their planned European site in Veendam, Netherlands, targets 2026 startup for similar outputs.

Production of U-232 and TFINER-relevant isotopes typically involves:Neutron irradiation in reactors (e.g., Th-232 targets yielding U-232 as a byproduct in thorium fuel cycles).

Proton or alpha-particle bombardment in accelerators (e.g., Th-232 + protons for Ra-228/Th-228/Ac-227).

Reactor methods require reprocessing facilities costing billions, with outputs limited to grams/year due to precursor scarcity (e.g., Ra-226 for Ac-227) and isotopic separation complexities.

Accelerator rates are ~1-2 g/day, demanding long runs and high maintenance.

Traditional setups like HFIR cost $50-100M/year to operate, while dedicated linacs run $500M-$2B to build. Short half-lives (e.g., Cf-254 at 60 days) necessitate rapid extraction/launch, adding logistical expenses.

Medical/Industrial Focus: 2025 facilities prioritize lighter isotopes (e.g., Mo-99/Tc-99m for diagnostics), with global markets valued at ~$4.7B, but heavy isotopes for space/industrial use remain niche and expensive.

Planned and Funded Isotope Related Projects for 2026-2027

U.S. Department of Energy (DOE) budgets for FY2026 ($7M for Radioisotope Processing Facility) and FY2027 emphasize expansion of the Stable Isotope Production and Research Center (SIPRC), $325M project at ORNL, with $88.8M awarded in 2024 for construction.

Medical Isotope Research Producer Facility (MIRP): Part of DOE’s FY2026 request, focusing on accelerator-based production for medical isotopes, with co-benefits for industrial ones.

European Expansions: SHINE’s Veendam facility (funded for 2026 startup) will produce 200+ GBq/week of I-131, while ASP Isotopes plans commercialization of enriched isotopes (e.g., via aerodynamic separation) by H2 2025, scaling into 2026-2027 for profitability.

Other Initiatives: NASA’s FY2026 budget supports isotope R&D for space propulsion, tied to TFINER Phase 2; Ratio Therapeutics/Nusano agreement (2025) funds multi-isotope supply for radiopharmaceuticals, extending to industrial uses by 2027.

Suitability for TFINER Isotopes: While not yet commercial in 2025, PWAs align with TFINER’s needs; e.g., Lawrence Berkeley’s work uses them for Pu-238 (similar to U-232), and they could scale for Cf-254/U-232 via proton/electron beams on thorium targets.

This addresses current challenges like low yields and high costs, and could make kilogram quantities viable for space propulsion.

In summary, PWAs do not yet define the best isotope production in 2025 but funded advancements position them to make U-232 and TFINER isotope creation easier and more affordable by 2026-2027, enabling compact, cost-effective facilities for medical, industrial, and space applications.