Atmospheric release model for the E-area low-level waste facility: Updates and modifications

Abstract

The atmospheric release model (ARM) utilizes GoldSim® Monte Carlo simulation software (GTG, 2017) to evaluate the flux of gaseous radionuclides as they volatilize from E-Area disposal facility waste zones, diffuse into the air-filled soil pores surrounding the waste, and emanate at the land surface. A schematic of the air pathway performance assessment (PA) analysis, after Dixon (2017), is shown in Figure E-1. The ARM is a PA model that will be treated as an "Engineering Calculation" and will not be used routinely, therefore it does not require a Software Quality Assurance Plan (SQAP). Each time results are created using ARM, the model will be design checked. This report documents the updates and modifications to the ARM for the next planned E-Area PA considering recommendations from the 2015 PA strategic planning team outlined by Butcher and Phifer ( 2016): 3.3 Non-Groundwater Pathways Calculation Improvements for Next PA Revision -RADON • Recommendation 75o Load inventory and start 1,000-year assessment period at end of E-Area LLWF Operations (beginning of IC).