Nuclear weaponsSandia makes sure U.S. nuclear weapons deterrent remain effective, credible

Published 28 July 2014

It may sound strange to say that nuclear weapons must survive radiation. Sandia National Laboratories says, however, that as part of its mission of ensuring the nation’s stockpile is safe, secure, and effective as a deterrent, the laboratory must make sure crucial parts can function if they are hit by radiation, especially a type called fast neutrons. Sandia developed a new way to do that after its facility for creating fast neutrons, the Sandia Pulsed Reactor (SPR), was shut down due to increased post-9/11 security concerns about its highly enriched uranium.

It may sound strange to say that nuclear weapons must survive radiation. Sandia National Laboratories says, however, that as part of its mission of ensuring the nation’s stockpile is safe, secure, and effective as a deterrent, the laboratory must make sure crucial parts can function if they are hit by radiation, especially a type called fast neutrons.

Sandia is responsible for non-nuclear components in all U.S. weapons systems and for overall system engineering and integration: pulling thousands of components together into a weapon.

It qualifies systems — ensuring their safety and effectiveness — through computer simulations and rigorous testing at unique facilities that mimic radiation environments a weapon could face during deployment or an accident.

Sandia developed a new way to do that after its facility for creating fast neutrons, the Sandia Pulsed Reactor (SPR), was shut down due to increased post-9/11 security concerns about its highly enriched uranium.

A Sandia Lab release reports that the laboratory created a science-based project called QASPR, Qualification Alternative to Sandia Pulsed Reactor. QASPR combines computer modeling and simulation, experiments and technology development, and draws on expertise throughout the labs, from materials science to transistor fabrication to sophisticated computer science. The idea is to create better radiation-hardened microelectronics for high-voltage transistors, part of a nuclear weapon’s safety electronics, and to offer a way to qualify the electronics without SPR.

Sandia does more modeling and experimental work than ever before to qualify components to survive the fast neutrons produced by a nuclear burst, either from an enemy weapon or one of our own exploding nearby, said QASPR project manager Len Lorence.

Both modeling, experimental work vital
“It’s very important both in the modeling and the experimental worlds that you not only get the right result but you get it for the right reason,” Lorence said. “It’s very important to understand the physics of what’s going on.”

Experiments don’t simply validate computer models. They are key to developing models in the first place. QASPR didn’t have the models it needed when it began in 2005. Researchers, however, had time to work on them because the next re-entry system that needed the tools and expertise for qualification was still years away.