The Truth About 3-D Printing and Nuclear Proliferation

December 14, 2015

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A recent article on additive manufacturing sounded the alarm over the use of this technology for the production of a nuclear weapon. While the authors, Matthew Kroenig and Tristan Volpe, are correct to assert that additive manufacturing is changing proliferation, today’s clear and present danger comes from conventional weapons, not just nuclear warheads. To sound an alarm over the latter and signal a call to action on these grounds risks obscuring the scope of this threat and underemphasizing some key issues.

First, it is currently easier to produce a conventional weapon than a nuclear weapon using additive manufacturing technology. Second, significant challenges remain in using additive manufacturing to produce components for nuclear weapons. Third, and perhaps most significantly, a focus exclusively on nuclear proliferation by way of additive manufacturing misses the broader problem. As sensitive information and materials become increasingly digital, they elude our traditional tools for controlling who accesses and uses them. This is a challenge we face for weapon of all kinds, including conventional and cyber — it is not a uniquely nuclear problem. Effective solutions will require a comprehensive approach.

3-D Printed Conventional Weapons Pose the Greatest Threat

Additive manufacturing is indeed a “game changer.” This flexible and cost-effective fabrication method has a number of uses, ranging from the rapid production of components for jet engines to the rendering of unique and fully functional replacement human heart valves. Additive manufacturing is a particularly useful tool for producing highly intricate objects that do not require large production runs. It’s a deceptively old technology dating back to the 1980s, when it began to be used for rapid prototyping. Today, use of the 3-D printers — the hardware for the additive manufacturing process — is increasingly common among traditional manufacturers, as well as in public libraries, art departments, and even in the food industry.

Without a doubt, weapons proliferation is an unintended consequence and a decidedly negative byproduct of this technology. The article’s authors do a service in highlighting this for the nuclear nonproliferation community. Yet while the widespread availability of 3-D printers and the ease with which computer aided design (CAD) files can be transferred may ultimately affect nuclear proliferation, they are affecting conventional weapons right now. Around the world, do-it-yourself gun enthusiasts are already using CAD files to quickly and cheaply print fully functional firearms at home.

The U.S. Department of State has been grappling with additive manufacturing’s potential for proliferation for over two years now. In 2013, the State Department’s Directorate of Defense Trade Controls sent a cease and desist letter to a nonprofit corporation in Texas called Defense Distributed to request the removal of CAD files for printing handguns from its server. These files were free and downloadable the world over. Indeed, by the time those particular files were taken down, they had been downloaded over 100,000 times. The Directorate of Defense Trade Controls requested that the site be taken down while it reviewed the issue on the grounds that posting these files to the Internet could constitute an unauthorized export of defense technologies controlled by the International Traffic in Arms Regulations. The State Department has since determined that CAD files containing instructions to print sensitive military equipment, including firearms, are indeed controlled under the International Traffic in Arms Regulations, but not before Defense Distributed sued the Secretary of State and others for violations of First, Second and Fifth Amendment rights. The court case is ongoing.

3-D Printed Nuclear Weapons are not Imminent

To temper alarm, it’s worth emphasizing that there are a number of controls already in place that can counter nuclear proliferation via additive manufacturing or traditional means, and that significant obstacles exist for using 3-D printing to obtain a nuclear weapon.

First, the Nuclear Suppliers Group currently places controls on the export of maraging steel, one of the only materials that can be used for the components of a uranium-enriching centrifuge. As the article mentions, the flow forming and axis-milling machines used in the traditional manufacturing process of maraging steel are also already controlled, as are the lasers that could be used to enrich uranium. Also, the maraging steel powder that could be used in the additive manufacturing version of centrifuge components is likewise already controlled as a function of being made of maraging steel. There’s nothing about the powder version that makes it more accessible through export channels than traditionally manufactured maraging steel.

Second, using 3-D printing to obtain a nuclear weapon is not a quick and easy process. Even if someone has a 3-D printer that can make centrifuge components, products made through additive manufacturing still require a great deal of finishing to become functional. That process requires expertise, and the methods for finishing are still in development. Maraging steel requires a great deal of post-processing, and it has been challenging to manufacture a 3-D printed material that has identical properties to its traditionally manufactured counterpart. This isn’t to say that we shouldn’t get out in front of the problem now, but it just isn’t as much a cause for alarm today as is the use of additive manufacturing to make conventional weapons.

A Symptom of the Bigger Problem

While existing regimes can be used to control a number of items potentially useful to the printing of lethal weapons, some controls over other items integral to the process will likely remain elusive. The 3-D printing proliferation concern exemplifies the threat from inevitable innovation combined with the digitization of the weapons we already possess. This is the fundamental challenge, and we face it on all fronts. Our risks increase as sensitive technologies and weapons become digital — and they are all becoming digital in some way.  The combination of innovation and digitization causes our existing controls and regimes to fail. Even when these regulations technically or legally apply to the technologies at hand, digitization makes it easier to bypass the rules.

For example: While one might try to place export controls on CAD files with instructions to print the cylindrical geometries found in centrifuge rotors, what is to prevent a nefarious actor from posting such a CAD file to the Internet? This problem is no different for conventional weapons or malware — there’s nothing unique in this regard about CAD files with instructions for making centrifuges. Though this is a concern across the U.S. government — initiatives from the Departments of Defense and Commerce have identified the threat — implementation of countermeasures remains slow.

What’s Been Done and How to Proceed

The issue of 3-D printing weapons has received widespread attention in articles that highlight the complexities associated with the Defense Distributed case, intellectual property rights, and the constitutionality of the control of technology in the public domain. The risks associated with additive manufacturing are also well known at the level of international regimes, such as the Wassenaar Arrangement, the Nuclear Suppliers Group, and the Missile Technology Control Regime, all of which have working groups made up of technical experts who continually update the lists of controlled technologies. These regimes haven’t yet been successful at managing the threat at this level because many of these technologies are dual-use and/or in development, not to mention the fact that the regimes are more accustomed to controlling objects than information. As such, it’s a steep hill to climb. Voices from industry also caution that further regulation could hinder innovation and competiveness.  Maintaining the U.S. technological edge in this area has been a priority for the current administration. Meanwhile, scholars have warned that the consequences of imposing regulations on these technologies could ultimately be harmful for U.S. security interests.

Clear next steps in curbing the nuclear proliferation threat via additive manufacturing lay  not in creating new multilateral frameworks, but in determining concrete requirements for controls based on the technical details of the relevant technologies. As this excellent article by Dr. Grant Christopher of Kings College points out, there is a clear logic to what technologies should next be addressed. Stakeholders should pursue controls over powder bed fusion printers, which can produce and use maraging steel. These powder bed fusion printers construct metal objects by melting and fusing powdered metals using either Selective Laser Sintering or Selective Laser Melting. Yet conversations about controlling these types of printers shouldn’t occur independently of conversations about controlling 3-D printers that are so large they can print an entire airplane wing. It’s critical that the dialogue not become stovepiped in this way.

Christopher also points out that one next step includes placing controls on printers and materials that could be used to 3-D print components critical to ballistic missile technology. Companies like Raytheon are already using additive manufacturing to create the components of a guided weapon, which can serve as a delivery system for a nuclear warhead. Additive manufacturing of these components can allow would-be proliferators to bypass export controls.

All of these concerns emphasize the ongoing challenge of controlling sensitive information increasingly available in digital format. Needless to say, this task is increasingly difficult.  While the U.S. government may have been a little late to the game, the issue is receiving attention at the highest levels across the interagency. No easy answers to this challenge exist. It certainly aids the cause to draw attention to the issue. But the rallying cry to control this technology due to the threat of nuclear proliferation risks stovepiping funding and efforts in this realm, as well as alienating the export control community already hard at work on these issues. Because this is a problem that spans the threat spectrum, stakeholders will be able to address it most efficiently and effectively if they approach it in a comprehensive fashion.


Amy Nelson is a Stanton Nuclear Security Fellow at the Council on Foreign Relations. She formerly worked as a research fellow at SIPRI North America, where she worked on the Future of Arms Control Project to evaluate the best use of arms control and best practices, and as a policy analyst at the U.S. Department of State, where she evaluated the impact of emerging technologies on existing export regulations and assesses the compatibility of these regulations with treaty and alliance goals.

Image: Nicolas Raymond, CC

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3 thoughts on “The Truth About 3-D Printing and Nuclear Proliferation

      1. Amy, sorry about the brevity of above comments. This is a really interesting article and I agree that strategic focus should be on conventional weapons where unlike nuclear fuel-cycle related goods this is probable, if not happening already, and not hypothetical. US export controls on maraging steel are seeming more restrictive than the NSG, but other countries may not.