Ignition Experiment Advances Nuclear Stockpile Stewardship Mission

To protect the material contained inside, the snout utilizes a 22-kilogram (or 50-pound) steel case to protect against the destructive force from significant amounts of X-rays and debris wind generated by megajoule-class ICF experiments. The snout is configurable, depending on the samples, materials or diagnostics used in future experiments.

The LLNL team in December successfully qualified the CryoXNBS fielding hardware, as well as the in-situ diagnostics, demonstrating that the snout can survive the extreme environment and perform according to expectations, Berzak Hopkins said.

“From the stockpile stewardship perspective, reaching ignition is a real testament to the enabling capabilities that help us assure the safety, reliability and resilience of our nuclear arsenal,” Berzak Hopkins said. “And from an energy standpoint, this demonstration of proof-of-principle is groundbreaking. Coupling those two together, it’s an inspirational moment, as it opens the door for an entirely new experimental capability that will now be enabled at NIF.”

Real-Time Diagnostics, Post-Test Analysis
In developing this integrated capability, NIF engineers built diagnostics into the CryoXNBS to get real-time data from the samples situated in the snout.

In fact, one of the first indications that ignition may have been reached during the December shot came from the diagnostics connected to the survivability experiment in the fielding hardware, said Brent Blue, National Security Applications program manager at NIF.

“It takes some time for the data to get pulled off the various NIF diagnostics in the target chamber, then move through the control system, and eventually get pushed to the viewers,” Blue said, noting that the diagnostics hooked up to the experiment in the CryoXNBS gave the groundbreaking data almost instantly.

“We knew right away that something big had just happened,” he said. “We got a very good measurement, so we were very excited for the result.”

In addition to real-time diagnostics, the team can retract the snout to outside the target chamber after a shot, disassemble it, and complete post-test examination of samples. The team is working on developing additional types of post-test analyses that inform their understanding of how materials behave under extreme environments that are produced by a detonating nuclear weapon.

Future Survivability Experiments
Following the successful qualification of the snout hardware in December, future experiments are planned at NIF to assess the response of a range of NNSA and Department of Defense stockpile components and subsystems to the threat-relevant environment created by igniting ICF capsules. Researchers are also planning to steadily expand the type of materials used in survivability experiments, placing more complex samples into the snout.

“Developing this capability is critical for stockpile stewardship,” Blue said, ”but it’s really a unique scientific capability that that doesn’t exist anywhere else in the world to be in such close proximity to these very high neutron flux environments. We are just on the cusp of discovering what we can do with this new capability.”