Zero-knowledge proofs are mathematical cryptographic methods to demonstrate the validity of a claim while providing no further information beyond the claim itself. The possibility of using such proofs to process classified and other sensitive physical data has attracted attention, especially in the field of nuclear arms control. This project demonstrates a non-electronic fast neutron differential radiography technique using superheated emulsion detectors that can confirm that two objects are identical without revealing their geometry or composition. Such a technique could form the basis of a verification system that could confirm the authenticity of nuclear weapons without sharing any secret design information.
Selected publication:
S. Philippe, R. J. Goldston, A. Glaser and F. d'Errico, "A Physical Zero-Knowledge Object-Comparison System for Nuclear Warhead Verification," Nature Communications, 7:12890 (2016).
Selected press coverage:
The New Yorker (Alex Wellerstein), Nature Physics (Mark Buchanan), PPPL and Princeton University, Popular Science, Cosmos Magazine.
Gaseous diffusion was historically the most widely used technology for military production of highly enriched uranium. Since June 2013, all gaseous diffusion enrichment plants worldwide are permanently shut down. The experience with decommissioning some of these plants has shown that they contain large amounts of uranium particles deposited in the cascade equipment. This project evaluated the potential of using uranium particle deposition models to understand and reconstruct the operating histories of gaseous diffusion enrichment plants. Through such “nuclear archaeology," this project provides a basis for the feasibility of verifying declarations by states of their past production of enriched uranium for weapons and civilian uses.
Selected publication:
S. Philippe and A. Glaser, Nuclear Archaeology for Gaseous Diffusion Enrichment Plants, Science & Global Security, Vol. 22, Iss. 1, 2014, pp 27-49.
Since September 11, 2001, the U.S. government has sought to remove weapons-useable highly enriched uranium (HEU) containing 20 percent or more uranium-235 from as many locations as possible because of concerns about the possibility of nuclear terrorism.
President Barack Obama worked to make this effort a global priority with biennial nuclear security summits between 2010 and 2016.
The primary focus of this HEU cleanout strategy has been on replacing HEU civilian research reactor fuel and uranium “targets” used in the production of medical radioisotopes with non-weapons-usable low-enriched uranium (LEU) fuel and targets. Eliminating the use of HEU in naval fuel was not on the agenda. Yet, naval reactors account for more than half of global HEU use and most of the global stockpile of HEU for nonweapons use. As the phase-out of other uses continues, naval reactors will become increasingly dominant among nonweapon users of HEU unless actions are taken to convert them as well.
Selected publication:
S. Philippe and F. von Hippel, "The Feasibility of Ending HEU Fuel Use in the U.S. Navy," Arms Control Today, November 2016.
To pursue reductions of anthropogenic global net emissions, knowledge of greenhouse gas sources and sinks is critical to define baselines, and assess the effectiveness of climate governance over time. Such information and the means to independently verify its credibility could be obtained through efficient transparency measures. It continue to remain out of reach, however, including in the recent Paris agreement.
This project tries to challenge this problem both intellectually and practically. In particular, it studies how transparency must be understood as both the addition of the notions of publicity and measurability to turn it into a credible information generating mechanism for governance.
Non-nuclear weapon state members of the Nuclear Nonproliferation Treaty (NPT) have the option to remove nuclear materials from international control for use in non-weapon military activities, for example nuclear propulsion of submarines. This option, sometimes referred as the NPT loophole, limits the power of the International Atomic Energy Agency to verify that nuclear materials are not diverted to pursue the development of nuclear weapons.
In this project, we developed the first comprehensive model for the application of safeguards on the naval nuclear fuel cycle in a military environment.
Selected publication:
S. Philippe, Safeguarding the Military Naval Nuclear Fuel Cycle, Journal of Nuclear Materials Management, Vol. XLII, No.3, 2014, pp 40-52.
Talk:
S. Philippe, The Naval Nuclear Fuel Cycle: Challenge and Opportunities for Governance, Mitigating Security and Proliferation Risks from Naval Nuclear Fuel George Washington University, August 27, 2018
Nuclear inspections, for example as part of arms control agreements, often involve compliance verification in sites to which inspectors have limited access. Traditionally, this necessitates the irreversible transfer of inspector-provided sensor equipment to the inspected parties prior to inspection. This can lead to competing interests between inspectors and inspected parties, for example concerning the frequency or intrusiveness of onsite inspections, and regarding the question of mutual trust in the sensor equipment. Meeting these requirements continues to be a challenge.
To address this problem, this project explore fundamentally new secure and trusted measurement approaches at the intersection of nuclear science, applied physics, and hardware security.
This article presents the first reassessment of the strategic rationality and credibility of French nuclear weapons policy before 1974. Building on untapped primary material from across the world as well as technical analysis, it shows that early Cold War French nuclear weapon procurement and deployment are incompatible with a precise grand design and the requirements of strategic rationality. The first generation of French nuclear forces also lacked technical credibility, despite reliance on outside help. Several French officials knew about it, as did their allies and adversaries. These findings de-exceptionalise French nuclear history and challenge conventional wisdom about Cold War nuclear history.
Publications:
B. Pelopidas and S. Philippe* (2020), “Unfit for purpose: reassessing the development and deployment of French nuclear weapons (1956–1974),” Cold War History, 1–18, published online.