UPDATES ON SALT REPOSITORY EXPERIMENTS AND SIMULATIONS

As part of the Department of Energy’s (DOE) Environmental Management (EM) and Nuclear Energy (NE) research programs into nuclear waste repositories, Los Alamos National Laboratory (LANL) has been involved in both experiments and simulations that seek to increase our understanding of the complex coupled processes that occur when hot waste interacts with salt formations in the underground. Specific objectives related to disposal system performance are defined in an update to the UFD Campaign Implementation Plan (McMahon, 2012). For 2013-2016 the research has been focused on using theory, experiments, and modeling in combination with existing underground research laboratory (URL) data to assess disposal system performance, including reduction of uncertainty associated with heat-generating nuclear waste (HGNW). HGNW is defined herein as the combination of both heat generating defense high level waste (DHLW) and civilian spent nuclear fuel (SNF). Thermal, hydrological, mechanical, and chemical (THMC) coupling and related modeling, as well as development of a field testing plan are called out in this objective.

In this presentation, we summarize recent advances in coupled heat and mass transfer in granular salt, including water/vapor migration, precipitation/dissolution, chemical reactions and in-situ subsurface evaporation. All of these processes are tied to the technical basis for disposal, spanning the operational, pre- and post-closure, and long term isolation of waste. Additionally, this work supports phased field thermal testing in salt planned for the underground at the Waste Isolation Pilot Plant (WIPP) that is expected to begin in early 2017.