Sampling and analysis validates acceptable knowledge on LANL transuranic, heterogeneous, debris waste, or ``Cutting the Gordian knot that binds WIPP``

Abstract

King Gordius tied a knot that was so intricate that an oracle proclaimed that whoever could undo it would be the next ruler of Asia. Alexander the Great cut it with his sword to claim the kingdom. By analogy, a Gordian knot has bound the Waste Isolation Pilot Plant (WIPP). The Los Alamos National Laboratory (LANL) and the Department of Energy (DOE) recently took one step closer to cutting this knot. Through sampling and toxicity characteristic leaching procedure (TCLP) analyses, LANL and the DOE validated that a LANL transuranic (TRU) waste (TA-55-43, Lot No. 01) was not a Resource Recovery and Conservation Act (RCRA) hazardous waste. This paper describes the sampling and analysis project as well as the statistical assessment of the analytical results. The analyses were conducted according to the requirements and procedures in the sampling and analysis plan (1) approved by the New Mexico Environment Department (2). The plan used a statistical approach that was consistent with the stratified, random sampling requirements of SW- 846 (3). LANL adhered to the plan during sampling and chemical analysis of randomly selected items of the five major types of materials in this heterogeneous, radioactive, debris waste. To generate portions of the plan, LANL analyzed a number of non-radioactive items that were representative of the mix of items present in the waste stream. Data from these cold surrogates were used to generate means and variances needed to optimize the design. Based on statistical arguments alone, only two samples from the entire waste stream were deemed necessary, however a decision was made to analyze at least two samples of each of the five major waste types. To obtain these samples, nine TRU waste drums were opened. Sixty-six radioactively contaminated and four non-radioactive grab samples were collected. Portions of the samples were composited for chemical analyses. In addition, a radioactively contaminated sample of rust-colored powder of interest to the New Mexico Environment Department (NMED) was collected and qualitatively identified as rust. The waste stream does not contain hazardous metals at or above regulated concentrations. The chemical TCLP analytical results for most of the RCRA metals were two to three orders of magnitude below the regulatory limits. Only cadmium, chromium, and barium were detected frequently enough to warrant statistical calculation of the upper confidence limits as required by