In the Belle, W. Va. accident, the sample taken for chemical analysis was removed from the surface of the plate rather than from the quarterthickness position. The phosphorus content was determined by photometric analysis (ASTM E3S0) and the sulfur by combustion-ti tration analysis (ASTM E395). (ii) In the Callao, Mo. accident, optical emission spectroscopy was used to determine all of the elements, including carbon.

A case is made for the use of short-term laboratory data in making predictions on the likelihood of significant colloid formation in supersaturated leachates of glass, under long-term repository conditions, using “accelerated tests” with a large ratio of the surface area of the glass to the leachate volume. In the repository conditions in which colloids can form, long-term leaching may be a kinetically-controlled process that involves the continuous formation of colloids. If this kinetic process dominates, it could lead to a significant increase in the predicted rates of radionuclide release. The question is whether or not colloids may form after prolonged times; the delayed formation would make it difficult to use short-term laboratory test results to represent (or predict) the long-term and cumulative effects of radionuclides. In this work, the pertinent long-term kinetic processes are identified in part. Classical nucleation theory for particle formation, as a potential condensation mechanism for colloid formation, is applied to explain pertinent experimental data on colloid formation. The classical theory, which is justified for this discussion, indicates that as supersaturation of a leachate is decreased, the nucleation rate decreases most significantly, while the incubation time increases at a small rate. As a result of this decreased nucleation rate, the significance of colloids tends to vanish, and usefulness of data from “accelerated“ laboratory tests may be applicable to long-term behavior.

Scatter in laboratory data with duplicates on Charpy impact tests is analyzed by identifying several sources of variability such as temperature, manganese sulfide, initial strain, mis-orientation, and notch radius in order to estimate the predictive 95% confidence intervals of the mean energy of absorption for each specific test temperature. Using a combination of real and virtual data on a high-strength pressure vessel grade steel (ASTM A517) over a range of temperatures from −40 °C (−40 °F) to 182 °C (360 °F), and the concept of a statistical design of experiments, we present an uncertainty estimation methodology using a public-domain statistical analysis software named DATAPLOT. A numerical example for estimating the mean, standard deviation, and predictive intervals of the Charpy energy at 48.9 °C (120 °F) is included. To illustrate the application potential of this methodology, we enhance it with formulas of error propagation to estimate the mean, standard deviation, and predictive intervals of the associated static crack initiation toughness, KIc. A discussion of the significance and limitations of the proposed methodology, and a concluding remark are given at the end of this paper.

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This report deals with technical information that is considered essential for demonstrating the ability of the high-level radioactive waste package to provide "substantially complete containment" of its contents (vitrified waste form or spent light-water reactor fuel) for a period of 300 to 1000 years in a geological repository environment. The discussion is centered around technical considerations of the repository. environment, materials and fabrication processes for the .vaste package components, various degradation modes of the materials of construction of the waste packages, and inspection and monitoring of the waste package during the preclosure and retrievability period, which could begin up to 50 years after initiation of waste emplacement. The emphasis in this report is on metallic materials. However, brief references have been made to other materials such as ceramics, graphite, bonded ceramic-metal systems, and other types of composites. The content of this report was presented to an external peer review panel of nine members at a workshop hc_d at thc Cc,tcr for Nuclear Waste Regulatory Analyses (CNWRA), Southwest Research Institute, San Antonio, q"cx:_s,April 2-4, 1996. The recommendaiions of the peer review panel have been incorporated in this report. There are two companion reports; the second report in the series provides state.of-the-art techniques for uncertainty evaluations. The methods provided in that report can i be used to quantify various types of uncertainties. The third companion report, on the basis of the information provided in lhc first two reports, devclops recommendations tbr the resolution of the issue of ,li "substantially complete containment" of high-level radioactive waste within the waste package, as