Subcritical nuclear tests remain useful for maintaining the U.S. nuclear weapons stockpile in the absence of nuclear explosive testing, the JASON defense advisory panel affirmed in a letter report last year. But “a gap exists in the current US capability to carry out and diagnose such experiments,” the panel said.
Subcritical experiments simulate aspects of nuclear explosions using chemical explosives. But since a subcritical mass of plutonium (or a surrogate material) is used, no actual nuclear explosion occurs.
The main purpose of subcritical experiments is to identify and decrease uncertainties in weapon performance. “For all weapons in the current stockpile, at the present time margins are adequate and uncertainties are within margins, both for normal operation and for nuclear safety should accidents occur,” the JASON panel said. “However, future aging of these weapons and their remanufacture may increase uncertainties, and JASON finds that scaled [subcritical] experiments in Pu [plutonium] may significantly reduce uncertainties that may arise in the future.”
But “JASON finds that x-ray radiography is needed to diagnose subcritical experiments in Pu… and that the US currently lacks adequate radiography at U1a [the nuclear complex in Nevada] for this purpose.”
The JASON letter report was prepared for the National Nuclear Safety Administration at the direction of Congress. A copy was released by NNSA last week under the Freedom of Information Act.
See Enhanced Capabilities for Subcritical Experiments, JSR-16-Task-011, October 7, 2016.
On Tuesday, December 23rd, the Department of Defense released its annual congressionally-mandated report on China’s military developments, also known as the “China Military Power Report,” or “CMPR.” The report is typically a valuable injection of information into the open source landscape, and represents a useful barometer for how the Pentagon assesses both the intentions and […]
Successful NC3 modernization must do more than update hardware and software: it must integrate emerging technologies in ways that enhance resilience, ensure meaningful human control, and preserve strategic stability.
The FY2026 National Defense Authorization Act (NDAA) paints a picture of a Congress that is working to both protect and accelerate nuclear modernization programs while simultaneously lacking trust in the Pentagon and the Department of Energy to execute them.
While advanced Chinese language proficiency and cultural familiarity remain irreplaceable skills, they are neither necessary nor sufficient for successful open-source analysis on China’s nuclear forces.