Sandia National Labs FY20 LDRD Annual Report

FY20 ANNUAL REPORT

Optical spectroscopy of plutonium project provides critical data for remote-sensing proliferation detection and nuclear detonation applications. There is a critical need to measure optical emission characteristics of plutonium (Pu) and its isotopes in high-temperature plasmas, such as those encountered in a detonation fireball or laser ablation plume. Previously, less than 20 unpublished transition probabilities (Einstein A coefficients) were measured using low-temperature lamps. The research team used laser-induced breakdown spectroscopy (LIBS) as a tool for creating high-density plasma and determining spectro-temporal signatures of Pu at high temperatures (3,000-8,000K), including the first published optical emission spectrum attributed to Pu oxides. The results are documented in the Atomic Plutonium Atlas, a comprehensive digital reference on the optical spectrum with thousands of energy levels and transition probabilities of atomic Pu. Through this work, critical data was provided on the identification and characterization of Pu in small samples for proliferation detection and in nuclear detonation remote- sensing applications. (PI: Sudeep Mitra)

First-published spectrum of Pu oxide emission using LIBS.

Integrated challenge defends the grid against high-altitude EMPs. Sandia’s EMP Grid Grand Challenge LDRD, which completed in September 2020, pioneered a comprehensive approach to defending the grid against high-altitude EMP (HEMP). The research team determined risk to the grid if a HEMP event were to occur, developed the ability to predict EMP-coupled insults to grid equipment, and conducted pulse tests up to 500kV. The probabilistic failure rates of equipment were identified and models established to understand grid cascading and how to dynamically recover. In addition, a polymer for transformer thermal management was created. Follow-on development and application work will continue in this emerging area of national security. (PI: Grant Biedermann)

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LABORATORY DIRECTED RESEARCH & DEVELOPMENT