Showing papers by "Atomic Energy of Canada Limited published in 2017"

Corrosion behavior of alloy 316L stainless steel after exposure to supercritical water at 500 °C for 20,000 h

Abstract: Oxidation behavior of alloy 316L stainless steel static capsules were investigated by long-term exposure to the supercritical water at 500 °C and 25 MPa for various exposure times. It was found that the thickness and weight gain vs. exposure time followed parabolic law. Elemental and phase analyses indicated that long-term exposure to the SCW resulted in formation of scales identified as Fe3O4 (outer layer), Mn-Fe-Ni-Cr spinel (inner layer) on the substrate, and Ni-enrichment (chrome depleted region) in the alloy 316L. Oxidation phenomena and scales grown on the Alloy 316L as the result of long term exposure to the supercritical water was discussed.

Spatial Autocorrelation, Source Water and the Distribution of Total and Viable Microbial Abundances within a Crystalline Formation to a Depth of 800 m

Abstract: Proposed radioactive waste repositories require long residence times within deep geological settings for which we have little knowledge of local or regional subsurface dynamics that could affect the transport of hazardous species over the period of radioactive decay. Given the role of microbial processes on element speciation and transport, knowledge and understanding of local microbial ecology within geological formations being considered as host formations can aid predictions for long term safety. In this relatively unexplored environment, sampling opportunities are few and opportunistic. We combined the data collected for geochemistry and microbial abundances from multiple sampling opportunities from within a proposed host formation and performed multivariate mixing and mass balance (M3) modeling, spatial analysis and generalized linear modeling to address whether recharge can explain how subsurface communities assemble within fracture water obtained from multiple saturated fractures accessed by boreholes drilled into the crystalline formation underlying the Chalk River Laboratories site (Deep River, ON, Canada). We found that three possible source waters, each of meteoric origin, explained 97% of the samples, these are: modern recharge, recharge from the period of the Laurentide ice sheet retreat (ca. ∼12000 years before present) and a putative saline source assigned as Champlain Sea (also ca. 12000 years before present). The distributed microbial abundances and geochemistry provide a conceptual model of two distinct regions within the subsurface associated with bicarbonate - used as a proxy for modern recharge - and manganese; these regions occur at depths relevant to a proposed repository within the formation. At the scale of sampling, the associated spatial autocorrelation means that abundances linked with geochemistry were not unambiguously discerned, although fine scale Moran's eigenvector map (MEM) coefficients were correlated with the abundance data and suggest the action of localized processes possibly associated with the manganese and sulfate content of the fracture water.

Method for non-destructive analysis of multiple structural parameters

Abstract: A system and method for non-destructive analysis of a structure. A probe acquires a transient time based reference signal and at least one test signal. The reference signal and test signals are transformed to the frequency domain. The frequency domain test signal can be normalized using the frequency domain reference signal. Parameters of interest are evaluated at each test location by iteratively determining estimated parameter values, generating an estimated frequency domain test signal using the estimated parameter values and determining the convergence between the estimated frequency domain test signal and the normalized frequency domain test signal. The parameters values are determined as the estimated parameter values resulting in a maximized convergence between the estimated signal and the normalized test signal. The parameter values can be used to visualize and model various features of the structure.

Framing Human-Automation Regulation: A New Modus Operandi from Cognitive Engineering

Abstract: Human-automated systems are becoming ubiquitous in our society, from the one-on-one interactions of a driver and their automated vehicle to large-scale interactions of managing a world-wide network of commercial aircraft. Realizing the importance of effectively governing these human-automated systems, there been a recent renaissance of legal-ethical analysis of robotics and artificial-intelligence-based systems. As cognitive engineers, we authored this paper to embrace our responsibility to support effective governance of these human-automated systems. We believe that there are unique synergies between the cognitive engineers who shape human-automated systems by designing the technology, training, and operations, and the lawyers who design the rules, laws, and governance structures of these systems. To show how cognitive engineering can provide a foundation for effective governance, we define and address five essential questions regarding human-automated systems: 1) Complexity: What makes human-automation systems complex? 2) Definitions: How should we define and classify different types of human-autonomous systems? 3) Transparency: How do we determine and achieve the right levels of transparency for operators and regulators? 4) Accountability: How should we determine responsibility for the actions of human-automation systems? 5) Safety: How do human-automated systems fail? Our answers, drawn from the diverse domains related to cognitive engineering, show that care should be taken when making assumptions about human-automated systems, that cognitive engineering can provide a strong foundation for legal-ethical regulations of human-automated systems, and that there is still much work to be done by lawyers, ethicists, and technologists together.