SST Sample Characterization Analysis of Archive Samples 102-C, 105-C, and 106-C
A substantial effort is planned to be initiated at the Hanford Site regarding the characterization of 149 single-shell tanks (SSTs) containing the byproducts of reprocessing during the 1950s and 1960s. Sampling and analysis, in distinct phases, are planned to involve laboratory investigations to determine both chemical and radionuclide inventories, so that waste disposal decisions can be developed. During 1989, trial analyses were performed on four archived samples from SSTs at the Pacific Northwest Laboratory using established U.S. Environmental Protection Agency (EPA) protocols and radiochemical procedures. The analysis of the archived SST waste material provides three important types of data for use in planning Phase I-A and Phase 1-B sample analysis. The types of data served as input to I) fi na 1 i zing the waste samp 1 e analysis procedures and methods and identify where procedure developmen~ may be needed, 2) evaluating the impact of normal paraffin hydrocarbon (NPH) lubricant {used in field sampling) on extracting inorganics or radionuclides from the SST sample, and 3) identifying trends in amounts of occupational radiation exposure expected from performing the various analysis procedures. Overall, the results are qualitative in nature, and the conclusions given are to be used with appropriate respect for the limitations of small amounts of data from four samples used in development processes. The results of the Phase I-A and I-B sample analysis will provide essential data for method performance for use in finalizing Phase I-C planning and methods development scope. Section 2.0, Inorganic Analysis, encompasses sample preparation, sample analysis, identification of methods performance limitations, and possible alternatives. Performance of the inorganic analytical methods was evaluated and changes were made to some of the procedures. In some cases, inductively coupled plasma-atomic emission spectroscopy (referred to in this report as ICP) did not provide the levels of accuracy and precision usually required for EPA work due to interference by other elements. In these cases, other methods are suggested as appropriate for trial as alternatives. In all cases, duplicates, spikes, and blanks were used to establish performance of the methods for the specific waste matrix. Results focused on problems in using the methods tested on the samples, the suitability of the ICP method of determining EP Toxicity metal ions and 22 EPA pollutant metal ions, and the suitability of cold vapor atomic absorption (CVAA) for mercury determinations. Problems areas identified are ICP spectral corrections, poor reproducibility from water leach and EP Toxicity methods, and adjustments needed for mercury analysis by CVAA. Section 3.0, Organics Analysis, details two screening procedures [total organic carbon (TOC) and gas chromatography (GC)], extraction procedures and related problems, surrogate spiking to test extraction efficiencies and matrix effects, and semivolatile organics via GC/mass spectroscopy (MS). The results show that the GC/MS is vulnerable to fouling and overload and that a combination of dilution and perhaps acidification are required to provide acceptable results. NPH and silicone-based lubricants from the sampling process impact the semivolatile analysis; however, with some modification the semivolatile method based on EPA SOW 288 can be used. Section 4.0, Radionuclide Analysis, evaluates procedures used to measure the radionuclides that might be found in the SST tank waste samples and establishes the level of accuracy and precision that can be expected. These data reveal that additional procedure development is needed in order to measure all of the radionuclides listed in Table 4-14 of the Waste Characterization Plan. In addition, the archive samples analyzed may not be representative of the tank population and considerable adaptation of the radiochemical procedures may be necessary to perform the desired measurements. NPH tests were conducted to determine whether the NPH from the field sampling process extracted significant quantities of the inorganics or radionuclides from the SST samples. Results indicate that no such extraction is anticipated; however, the NPH does have a significant effect on the organic analysis and its use should be investigated. Trends in expected occupational exposure were obtained by measuring the radiation level of samples and having the analysts record estimates of the contact time with the samples. Data revealed that the analysts received no significant exposure and that, as expected, the potential dose is directly proportional to the sample size and handling times.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- DE-AC06-76RL01830
- OSTI ID:
- 1086603
- Report Number(s):
- PNL-7258
- Country of Publication:
- United States
- Language:
- English
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