Workers at the NNSS prepare to insert a canister holding explosives and diagnostic equipment into a 31-meter deep hole in preparation for the SPE-6 experiment. Courtesy/LANL
Last month, Los Alamos National Laboratory participated in the National Nuclear Security Administration’s (NNSA) sixth detonation of an underground conventional explosive at the Nevada National Security Site (NNSS) as part of its ongoing Source Physics Experiment (SPE) series.
SPE seeks to improve the nation’s capability to detect and characterize underground nuclear explosions to help develop an advanced capability for the United States to monitor low-yield nuclear testing.
“By conducting the experiments near the location of previous underground nuclear tests, we are more able to compare data between conventional and nuclear explosions,” said Cathy Snelson, R&D manager in Geophysics at the Laboratory. “This helps us improve the U.S. capability to differentiate low-yield nuclear test explosions from other seismic activity, such as mining operations and earthquakes.”
This sixth experiment (SPE-6) included a chemical explosive equivalent to 2,200 kilograms (about 5,000 pounds) buried 31 meters (more than 100 feet) underground. Researchers collected a multitude of data types for analysis including seismic, infrasound, optical, acoustic, geospatial, and electro-magnetic with technologies such as high-resolution accelerometers, high-speed video, air- and ground-based photogrammetry, as well as synthetic aperture radar (SAR). Seismic data from the SPE series are uploaded to the Incorporated Research Institutions for Seismology website at http://www.iris.edu/hq/ for sharing and analysis by researchers around the world following a two-year data hold policy.
SPE-6 marks the end of Phase I of the SPE series. These six experiments were conducted in granite (hard rock) at different depths and explosive weights. Phase II of SPE will focus on explosions in alluvium (weak rock). These different SPE phases allow researchers to determine the general role that geology plays in affecting seismic waves generated by underground nuclear explosions. The five explosions planned for Phase II will be conducted during fiscal year 2018.
“The Source Physics Experiment series and NNSA’s ongoing research and development at our National Laboratories are key to strengthening our national security. These efforts advance technical solutions for treaty monitoring by the United States and its partner nations,” said Anne Harrington, NNSA Deputy Administrator for Defense Nuclear Nonproliferation.
The SPE team comprises researchers from NSTec, Lawrence Livermore National Laboratory, Los Alamos National Laboratory, Sandia National Laboratories, the University of Nevada-Reno, the Air Force Technical Applications Center, and the Desert Research Institute.