斯德哥尔摩国际和平研究所-Is-three_12页_409kb

3D Printing and Nuclear Proliferation: A Summary

I. Introduction

Three-dimensional (3D) printing is a rapidly evolving manufacturing technology that can produce objects from plastics and metals by layering materials. It is increasingly used in industrial and aerospace applications for creating complex, detailed parts. While the technology is widely used in low-technology fields like consumer goods and art, concerns have been raised about its potential misuse in nuclear proliferation, particularly in the production of nuclear weapons or components.

The paper explores whether 3D printing could be exploited to bypass nuclear proliferation barriers, especially by non-state actors. It concludes that while 3D printing may have some limited applications in nuclear-related industries, it is not a viable method for producing complete nuclear weapons.

II. 3D Printing Technology

Overview

3D printing, also known as additive manufacturing, builds objects by adding layers of material, typically in a powder form, which are selectively melted by a laser. This process is guided by computer-aided design (CAD) models and is significantly different from traditional subtractive manufacturing, which involves removing material from a larger block to shape the final product.

Applications

• Low-technology uses: 3D printing is already used for creating intricate plastic parts, such as chess pieces, with high flexibility and cost-effectiveness.
• Rapid prototyping: Engineers can use 3D printing to create detailed prototypes for testing and display purposes, even for complex nuclear systems.
• Industrial scale: While 3D printing can be efficient for producing repetitive parts, it is not yet suitable for large-scale, high-precision manufacturing in nuclear industries.

III. 3D Printing Nuclear Weapon Components

Explosives

• 3D printing of explosives: The only known public reference to 3D printing of explosives comes from Los Alamos National Laboratory, which explored safer explosive materials and their behavior.
• Challenges: High explosives are dangerous and difficult to process. Traditional methods are limited to state actors due to specialized equipment and safety concerns.
• Potential: 3D printing could offer a safer and more accessible method for producing precision explosive parts, though it is not yet a practical alternative to current techniques.

Fissile Materials

• Plutonium: Highly radiotoxic and pyrophoric, plutonium requires careful handling in a vacuum or argon atmosphere. While it is theoretically possible to 3D print a plutonium shell or sphere, the process is extremely dangerous and unproven.
• Uranium: Less radiotoxic than plutonium, but still pyrophoric. Uranium printing is more difficult due to its high melting point, but the metallurgy is simpler than that of plutonium.

Reconstructing Damaged Parts

• Scenario: Non-state actors could potentially recover fissile material from a damaged weapon and use 3D printing to reconstruct parts.
• Feasibility: While possible in theory, the process would require advanced equipment and precise handling. The paper suggests that this is a very remote possibility and that the actor would likely be unsuccessful but highly motivated.

Beryllium and Aluminium

• Beryllium: Used in nuclear weapon cores as a neutron reflector, but difficult to 3D print due to its brittleness and reactivity.
• Aluminium alloy: A potential compromise, as beryllium-aluminium alloys are more suitable for 3D printing. However, the availability of printing-grade beryllium is limited, and export controls may pose a challenge.

IV. 3D Printing in Uranium Enrichment

Gas Centrifuges

• Function: Gas centrifuges are used to enrich uranium by separating U-235 from U-238. They are complex mechanical devices with precision requirements.
• Rotor: The most critical component of a gas centrifuge is the rotor, which spins at hypersonic speeds and must withstand extreme forces. Current materials like aluminium alloys and carbon fibre are used, and 3D printing is unlikely to match their strength or durability.

Other Components

• End caps and baffles: These parts require high strength and are typically made using traditional methods.
• Shaft, bearing, and motor susceptor: These components also need exceptional strength and are usually manufactured from steel, making 3D printing a less attractive option.

Conclusion

• 3D printing and nuclear weapons: The idea of 3D printing a complete nuclear weapon is not credible due to the technical, material, and safety challenges involved.
• Supporting parts: 3D printing may be useful for producing some non-critical parts in nuclear systems, but it does not offer a significant advantage over traditional manufacturing.
• Non-state actors: While 3D printing could theoretically aid non-state actors in certain scenarios, such as reconstructing damaged components, it is unlikely to provide a major pathway for nuclear proliferation.
• Policy implications: European export regimes need to remain vigilant about the potential misuse of 3D printing in nuclear contexts, especially regarding materials and safety requirements.

Key Points

• 3D printing is not a viable method for producing complete nuclear weapons.
• It may be useful for certain non-critical components, but not for the core of a weapon or complex machinery like gas centrifuges.
• Non-state actors may have limited interest in full-scale nuclear proliferation due to the complexity and resource requirements.
• Specialized materials and environments are required for 3D printing in nuclear contexts, making it less accessible than traditional methods.

References

• Tirone, D. C. and Gilley, J. (2015). 'You can print your own guns at home. Next it will be nuclear weapons. Really'.
• Daily Mail (2016). 'Could 3D printing trigger World War 3? Expert warns technology could allow rogue states to manufacture nuclear weapons'.
• Baker, R. D., Hecker, S. S. and Harbur, D. R. (1983). 'Plutonium: a wartime nightmare but a metallurgist's dream'.
• Clancy, T. (1991). The Sum of All Fears.
• Angelo, J. A. (2004). Nuclear Technology.

Author

• Robert Kelley is a licensed nuclear engineer in California with experience in nuclear weapon research and non-proliferation efforts. He has worked at the Lawrence Livermore National Laboratory and the International Atomic Energy Agency (IAEA).