This short course will demonstrate a workflow that can support probabilistic safety assessment using the simulation and analysis tools in GDSA Framework. The GDSA Framework tool can help simplify, automate, and replicate the creation and submission of multiple simulation runs in a graphical environment. The presentation will cover three main elements: the GDSA workflow tool which allows one to build and execute an automated workflow, PFLOTRAN for subsurface simulation and groundwater flow and transport modeling, and Dakota for uncertainty and sensitivity analysis. The demonstration will cover the use of sampling methods for uncertainty analysis of a simple PFLOTRAN case study. We will highlight the use of the workflow to set up and launch multiple simulations, along with pre- and post-processing tools for analysis. The format of the class will be two hours of presentation and software demonstrations, followed by an optional hour for people who wish to run the GDSA Framework on a virtual machine. Participants are encouraged to bring a laptop if interested in this.