Single-shell tank constituent rankings for use in preparing waste characterization plans

Abstract

This effort is part of the initial exploratory characterization efforts for mixed wastes in underground single-shell tanks (SSTs) at the U.S. Department of Energy's (DOE) Hanford Site being conducted in accordance with DOE's waste characterization plan (Winterset al. 1g89). The purpose of this analysis was to provide a preliminary ranking of the constituents in the SST waste and provide information for use in establishing detection limits for the analytical characterization of the wastes. This report documents past efforts for use in ongoing SST characterization efforts. The bulk of the efforts described were conducted from April 1988 to September 1989. Since then, only minor corrections and updates have been made. Although the results from these efforts have been one source of information in the ongoing process of defining contaminants, the lists and their rationale are no longer current. The early nature of these efforts is evident in the use of tank groupings other than operable units that have been subsequently defined by the Federal Facilities Agreement and Consent Order (Tri-Party Agreement). This report provides a starting point for a planned update of the efforts described in this report.

Operational tank leak detection and minimization during retrieval

“…First, constituents of concern (COCs) were established from a risk standpoint. The COCs developed are presented in Table 1 and were primarily drawn from data in Droppo (1991). Droppo determined that constituents that resulted in a potential carcinogenic risk (R) greater than 1 .O E-06 or a non-carcinogen hazard index (HI) greater than 1 .O, based on the transport model used, were to be considered COCs.…”

Development of a risk-based approach to Hanford Site cleanup

“…Unit risk factors were generated using the Multimedia Environmental Pollutant Assessment System (MEPAS) Application Guidance (Buck et al 1995) for each contaminant of concern. A unit transport factor was estimated for a single "unit" source (e.g., curie, gram,) of each contaminant, in (a) See, for example, the Hanford Defense Waste EIS (DOE 1987), Droppo et al (1991), Buck et al (1991), Kincaid (1994), Wood (1994), and Napier (1995).…”

Clean option: An alternative strategy for Hanford Tank Waste Remediation. Volume 2, Detailed description of first example flowsheet

“…In general, these standard represent a high level of risk reduction. However, for the Hanford tank wastes, several assessments (Droppo et al 1991;Buck et al 1991) have indicated that, if not retained within the disposal system, Tc-99, 1-129, and U-238 are primary contributors to long-term radioactivity-related risk even at concentrations allowed by the Class A limit. Thus, the clean option goals include an additional reduction for these constituents.…”