Short-Pulse Interrogation for Detection of Special Nuclear Materials

Yuri Podpaly | 19-FS-034

Project Overview

The focus of our project was a simulation and experimental effort to develop a technique for detecting and differentiating fissionable materials. This effort was a combined project between Lawrence Livermore National Laboratory and Mission Support and Test Services (MSTS), leveraging experimental resources at the Nevada National Security Site (NNSS). The work builds on a previous Livermore effort to use a neutron source with a short pulse to identify fissionable materials from an induced prompt fission effect and a MSTS effort to build a mobile, self-contained dense plasma focus (DPF) for interrogation missions.

In this project, we (1) ran extensive Monte Carlo N-particle simulations with neutrons and gamma rays with a variety of interrogated objects; (2) discovered optimal distances for detector operation; and (3) identified a potential pulse-gating mechanism that minimizes the need for shielding. Experimentally, we performed two campaigns at the Nevada National Security Site. The first campaign provided confirmation of the method for functionality with depleted uranium and non-fissionable objects. The second campaign was completed with highly enriched uranium and received qualitative confirmation of the operation of this methodology with special nuclear materials (SNM).

This project continued to optimize the short-pulse detection method, including (1) identifying optimal detector locations; (2) identifying an algorithm for minimizing detector shielding; (3) further simplifying gamma and neutron identification; (4) performing a confirmation experiment with depleted uranium; and (5) performing the first DPF experiments using SNM and the short-pulse detection methodology. The experimental tests were the first demonstration of this method using a mobile DPF, which further demonstrates the applicability of this method to field use.

Mission Impact

Overall, these efforts resulted in developing and demonstrating a tool that supports Livermore's nuclear threat reduction mission research challenge, and can support the NNSA mission in proliferation detection and verification technologies.

Publications, Presentations, and Patents

Gall, B., et al. 2019. "Portable Dense Plasma Focus Neutron Source for Mobile Nuclear Non-Proliferation Applications." IEEE Pulsed Power and Plasma Science Conference, Orlando, FL, 2019. DOE/NV/036240544.