Speaker: Anemarie DeYoung,

Neutron Science and Technology, P-23, LANL

NDSE First Static Special Nuclear Material Experiment

Abstract: 

Because of the Neutron Diagnosed Subcritical Experiment (NDSE) LDRD Project, a major experimental program is being executed in Nevada with a variety of NCERC static nuclear reactive targets, with the final objective of establishing the accuracy of the NDSE technique for interrogating subcritical objects containing Highly Enriched Uranium (HEU). This necessitated designing and constructing a test stand, which includes all necessary shielding, along with the Dense Plasma Focus (DPF) neutron source and detector design and installation. All the experiments have been simulated with high resolution MCNP6 transport code calculations, in order to understand the details of the complex neutron scattering reactions and background sources that are included in the detector signals. The DPF source DT burn has been simulated using the LA-COMPASS code and nuclear post-processor. The current DPF-based system looks promising for reaching the NDSE measurement goal of D k_eff < 0.3%.

Through this work, the laboratory and the nation have the opportunity of putting in place by the early 2020’s, a facility that has the capability to measure alpha reaction history, similar to traditional reaction methods employed during testing. Modeling studies have shown that the reactivity measurement capability proposed here would serve a compelling set of missions in Stewardship and Global Security. This capability is a game-changer, enabling the Stockpile Stewardship Program to meet its responsibility to assess the effects of aging and manufacturing process changes, evaluate proposed approaches to Life Extension Programs, inform Significant Finding Investigations and address other issues that affect the viability and safety of the current and future stockpile and our ability to deal with global threats.