Some deficiencies in analyzing leachates and reporting results

Abstract

Determination of the Teachability of elements from various waste forms for long-term retention of radioactive wastes requires chemical analysis of both the leachate and waste form for the various elements or radionuclides of interest. Neither the precision of the leaching procedure nor the accuracy of the results can be determined unambiguously if gross uncertainties exist in either the analytical methods used or the way in which the results are reported and/or interpreted. Perhaps the most important consideration is to demonstrate beforehand that all participating laboratories can obtain the same analytical result within some stated uncertainty when the same concentration is known to be present, i.e., by analysis of a single homogeneous solution. Special precautions must be taken to ensure that all material leached from the waste form is recovered from the leaching container and that all refractory particles are dissolved completely before analysis is begun. The actual results obtained should be reported, including negative signs if present, avoiding all subjective and quantitatively nondescriptive statements such as nil, none, not detected, etc. Each result must be accompanied by an estimate of its uncertainty which must include all random uncertainties incurred anywhere in the entire measurement process, preferably expressed as the standard deviation. Problems involved in interlaboratory comparisons are also discussed.

Materials characterization center workshop on compositional and microstructural analysis of nuclear waste materials. Summary report

“…However, experiences reported by several workshop participants (ASTM C 26.05 Draft 3 1980;Sill 1980;ASTM Subcommittee D-19.12 1980;Powell et al 1979) emphasized that the assumption that all laboratories obtain similar data is very likely to be wrong. The primary source of this conclusion was the personal experiences of several participants with analytical round-robin test series.…”