A comprehensive and systematic approach to developing and documenting conceptual models of contaminant release and migration at the Hanford Site

The U. S. Department of Energys Richland Operations Office has initiated efforts to adapt and implement the features, events, and processes (FEP) methodology used in scenario development for nuclear waste disposal programs to the environmental management and remediation problems facing the Hanford site. These efforts have shown that modification of the FEPs methodology to incorporate the use of process relationship diagrams (PRD) is effective in facilitating the development of conceptual models and selection of potentially relevant factors (i.e., FEPs) to be incorporated into a specific environmental assessment. In adopting this methodology for Hanford, a master PRD was created to provide a structure to identify these factors and to illustrate the relationships among them. The organizational framework of the master PRD was developed to match the organization of current Hanford site-wide environmental assessment activities and to facilitate screening of the FEPs relevant to the specific assessments needed for the site.