Nuclear weaponsSled track simulates high-speed accident in B61-12 nuclear weapon test

Published 10 October 2016

Sandia National Laboratories has sent a mock B61-12 nuclear weapon speeding down the labs’ 10,000-foot rocket sled track to slam nose-first into a steel and concrete wall in a spectacular test that mimicked a high-speed accident. It allowed engineers to examine safety features inside the weapon that prevent inadvertent nuclear detonation. Data analysis from the test continues, and the information will help engineers better understand how systems respond in abnormal environments — accidents or other unexpected events.

Sandia National Laboratories has sent a mock B61-12 nuclear weapon speeding down the labs’ 10,000-foot rocket sled track to slam nose-first into a steel and concrete wall in a spectacular test that mimicked a high-speed accident. It allowed engineers to examine safety features inside the weapon that prevent inadvertent nuclear detonation.

Data analysis from the test continues. Sandia teams will use the information in collaboration with colleagues at Los Alamos National Laboratory to hone their understanding of how systems respond in abnormal environments — accidents or other unexpected events.

The test, part of a B61-12 abnormal environments series, used a test unit that resembled an actual weapon as much as possible, said test director Jason Petti. The high-fidelity unit contained standard components that make up a weapon, explosives and other hazardous materials, but did not contain any enriched uranium or plutonium, Petti said.

Sandia Lab says that the complex forward ballistic test used rocket motors to accelerate the sled along the track, releasing the B61-12 unit to a free-flight crash. The test met expectations and demonstrated the team’s ability to design and implement high-consequence tests. It built on past success for the B61-12 program from 2014 and 2015, when the labs crashed a rocket sled into a stationary mock weapon in a reverse ballistics test series, considered normal environment tests.

“Abnormal environment tests are performed to benchmark the performance of safety features designed into weapons,” said Matt Brewer, lead test engineer. The simulated accident collected data to ensure the weapon met its safety requirements.

Test evaluated weapon performance, helped computer models
Sandia engineers designed the 9 March test both to evaluate the weapon’s performance and to calibrate a computer model that predicts what can happen to a weapon under various conditions, Brewer said.

John Sichler, lead for the Center Bomb Subassembly Product Realization Team, said designing a weapon system to remain safe even after an accident is extremely challenging.

Test results help improve solid mechanics models, he said. Because tests are expensive and it’s not feasible to re-create every possible accident scenario, computer models fill in the gaps by simulating other scenarios.

“We will use the models to predict how our nuclear safety components will perform in numerous postulated accident scenarios without actually conducting tests,” Sichler said. “Over the past five years we’ve been improving our models. It’s remarkable how good they have become.”