Determining Importance and Grading of Items and Activities for the Yucca Mountain Project

Raytheon Services Nevada (RSN), in support of the Department of Energy's (DOE) Yucca Mountain Project, has been responsible for the Title II designs of the initial structures, systems, and components for the Exploratory Studies Facility (ESF), and the creation of the design output documents for the Surface-Based Testing (SET) programs. The ESF and SET programs are major scientific contributors to the overall site characterization program which will determine the suitability of Yucca Mountain to contain a proposed High Level Nuclear Waste (HLNW) repository. Accurate, traceable and objective characterization and testing documentation that is germane to the protection of public health and safety, and the environment, and that satisfies all the requirements of 10 CFR Part 60(1), must be established, evaluated and accepted. To assure that these requirements are satisfied, specific design functions and products, including items and activities depicted within respective design output documents, are subjected to the requirements of an NRC and DOE-approved Quality Assurance (QA) program(2). An evaluation (classification) is applied to these items and activities to determine their importance to radiological safety (ITS) and waste isolation (ITWI). Subsequently, QA program controls are selected (grading) for the items and activities. RSN has developed a DOE-approved classification process that is based on probablistic risk assessment (PRA) techniques and that uses accident/impact scenarios. Results from respective performance assessment and test interference evaluations are also integrated into the classification analyses for various items. The methodology and results of the RSN classification and grading processes; presented herein, relative to ESF and SET design products; demonstrates a solid, defensible methodological basis for classification and grading.