Panel on Nonproliferation and Safeguards Aspects of Fusion (Some Visuals)

Summary

This presentation explores the proliferation and safeguards challenges associated with emerging commercial nuclear fusion technologies. It highlights the potential for covert fissile material production (such as Pu-239 or U-233) due to intense neutron fluxes in DT fusion reactors and advocates for proactive technical design and early IAEA safeguards integration.

Slide 1: Title Slide

PANEL ON NONPROLIFERATION AND SAFEGUARDS ASPECTS OF FUSION (SOME VISUALS)

Alexander Glaser Princeton University

66th Annual INMM Meeting Washington, DC, August, 2025 Revision 1 Source: Universal Pictures

Slide 2: Nuclear Fusion in 2025

NUCLEAR FUSION IN 2025

For many decades, largely a government-led effort, but fusion R&D is increasingly conducted by startups and/or involves public-private partnerships:

At least 45 companies are seeking to commercialize fusion energy
More than $7 billion in funding
More than 1,000 scientists and engineers recruited per year

Most concepts pursued for energy applications are based on magnetic confinement fusion and rely on the DT fusion reaction: D + T → 4He + n + 17.6 MeV In-situ tritium breeding, primarily via: n + 6Li → 4He + T + 4.8 MeV

Source: The Global Fusion Industry in 2024, Fusion Companies Survey by the Fusion Industry Association, Fusion Industry Association, 2024

Slide 3: Global Nuclear Explosive Material Inventory

There is enough nuclear explosive material in the world to make over 200,000 nuclear weapons

1240 tons of highly enriched uranium (HEU) Each block corresponds to 12 kg of HEU, the amount necessary to make a fission bomb; about 100,000 bombs-worth total
565 tons of separated plutonium Each block corresponds to 4 kg of plutonium, the amount necessary to make a fission bomb; about 140,000 bombs-worth total

Graphic/concept by Alex Wellerstein and Tamara Patton Inventory estimates from fissilematerials.org Status as of beginning of 2024

Slide 4: Fissile Material Production Potential of Nuclear Fusion Reactors

FISSILE MATERIAL PRODUCTION POTENTIAL OF NUCLEAR FUSION REACTORS

FUSION REACTORS AS NEUTRON-RICH ENVIRONMENTS Standard operation of a fusion reactor does not involve nuclear materials, which offers significant nonproliferation benefits compared to nuclear fission reactors; the presence of intense neutron fluxes provides an environment, however, that could be used for covert production of fissile materials.

HOW MUCH FISSILE MATERIAL COULD POSSIBLY BE PRODUCED? Previous analyses have shown that a commercial-scale reactor with a fusion power of 1500 MW (600–750 MWe) could be used to make on the order of 10 kg of Pu-239 or U-233 per week.

Source: iter.org (top); A. Glaser and R. J. Goldston, Proliferation Risks of Fusion Energy: Clandestine Production, Covert Production, and Breakout, Nuclear Fusion, 52 (4), 2012

Slide 5: Plutonium Buildup in the Blanket

PLUTONIUM BUILDUP IN THE BLANKET (1500 MW OF FUSION POWER; 25 TRISO PARTICLES/CC IN BREEDING CHANNELS)

In the reference scenario, about one significant quantity of plutonium builds up in one month.
Depending on the blanket type (Molten Salt [Flibe] vs Dual Coolant Lithium Lead [DCLL]), 60–85 MW of fission power are generated throughout the process.
Note that more aggressive production scenarios could deliver 8–10 kilograms of plutonium per week.

References:

A. Glaser, R. J. Goldston, P. Huber, Detectability of Covert Fissile Material Production in Nuclear Fusion Reactors via Antineutrino Emissions, August 2025, arxiv.org/abs/2508.16358
A. Glaser and R. J. Goldston, Proliferation Risks of Fusion Energy: Clandestine Production, Covert Production, and Breakout, Nuclear Fusion, 52 (4), 2012

Slide 6: Addressing Dual-Use Aspects of Fusion: A Proactive Approach

ADDRESSING DUAL-USE ASPECTS OF FUSION: A PROACTIVE APPROACH

FUSION TECHNOLOGY

Consider (and prioritize) system configurations and materials that make military use difficult, especially with regard to fissile material production (and tritium diversion).
Design reactors and other test facilities with inspections and verifiability in mind.

POLICY & REGULATION FOR NUCLEAR FUSION

Acknowledge that nuclear fusion reactors can raise security (and safety) concerns.
Involve, at an early stage, the International Atomic Energy Agency on how to monitor fusion reactors.

Source: Max Planck Institute for Plasma Physics (top) and iaea.org (bottom)