Approach to Characterizing and Evaluation Alternatives for the Decommissioning of Sub-Grade Structures at the Plutonium Finishing Plant

摘要

In 2002, the Richland Operations Office of the U.S. Department of Energy (DOE), the U.S. Environmental Protection Agency (EPA), and the Washington State Department of Ecology (Ecology) developed milestones for transitioning the Plutonium Finishing Plant (PFP) facility to a clean slab-on-grade configuration. The milestones required developing an engineering evaluation/cost analysis (EWCA) for the facility's subgrade structures and installations as part of a series of evaluations intended to provide for the transition of the facility to a clean slab-on-grade configuration. In addition to supporting decisions for interim actions, the analyses of sub-grade structures and installation performed through this EE/CA will contribute to the remedial feasibility study(ies) and subsequently to the final records of decision for the relevant operable units responsible for site closure in the 200 West Area of the Hanford Site. To preclude the cost of extensive sampling and analysis, the approach to characterizing the PFP sub-grade was to use all available historical data to provide the information necessary to describe the sub-grade items accurately and to characterize the process wastes carried through the individual pipeline, diversion boxes and installations. Historical records from original sources including operator's handwritten logs were researched to determine the chemicals used and the number, location and volume of unplanned releases of waste constituents to the soil. Additionally, historical photographs were used to help ensure all process waste lines were identified as to their original and final configuration. Plutonium processing flow diagrams were used to identify the Comprehensive Environmental Response Compensation and Liability Act of 1980 (CERCLA) hazardous constituents of concern.