Quality assurance criteria for Waste Isolation Pilot Plant performance assessment modeling

The US Department of Energy (DOE) is developing the Waste Isolation Pilot Plant (WIPP) as a deep geologic repository for transuranic (TRU) and TRU-mixed wastes generated by DOE Defense Program activities. Regulatory agencies, including the Environmental Protection Agency (EPA) and New Mexico Environment Department, will be forced to rely upon system modeling to determine the potential compliance of the WIPP facility with federal regulations. Specifically, long-term modeling efforts are focused on compliance with 40 CFR Part 268, ''Land Disposal Restrictions,'' and 40 CFR Part 191, ''Environmental Radiation Protection Standards for Management and Disposal of Spent Nuclear Fuel, High-Level, and Transuranic Radioactive Wastes.'' DOE plans to use the similar conceptual models and numerical codes to demonstrate compliance under both of these regulations. Sandia National Laboratories (SNL) has been developing a system model that will be used to demonstrate potential waste migration from the WIPP facility. Because the geologic system underlying the WIPP site is not completely understood, the software code to model the system must be developed to exacting standards for its predictions to be reliable and defensible. This is a complex model that consists of many submodules used to describe various migration pathways and processes that affect potential waste migration