The Canadian Nuclear Safety Commission (CNSC; French: Commission Canadienne de sûreté nucléaire) is the federal regulator of nuclear power and materials in Canada. In addition to nuclear power plants and nuclear research facilities, the CNSC regulates numerous other uses of nuclear material such as radionuclides used in the treatment of cancer, the operation of uranium mines and refineries, and the use of radioactive sources for oil exploration, and in instruments such as precipitation measurement devices. The CNSC is an agency of the Government of Canada which reports to the Parliament of Canada through the Minister of Natural Resources.
Early detection of damage in reinforced concrete structures is critical for ensuring structural safety and reducing maintenance costs. Acoustic emission monitoring offers a passive means of capturing stress-induced damage activity; however, conventional analysis approaches rely heavily on manual interpretation of signal features. This paper proposes an artificial intelligence framework that integrates acoustic emission data with machine learning for automated early failure detection. A one-class support vector machine is employed to learn baseline undamaged behavior and identify deviations associated with damage initiation. The approach is experimentally validated using pull-out tests on reinforced concrete specimens with varying configurations. Results demonstrate that the proposed framework detects damage onset in real time and provides reliable early warning prior to visible failure. Feature-level analysis further highlights the relative effectiveness of different acoustic emission parameters for damage characterization.
Radiation-based medical techniques and devices provide significant benefits to patients through the diagnosis, treatment, and management of illness and disease. Documenting trends and frequency of use offer important insights into radiation protection and help address gaps in the documentation of medical exposures. Here, we present the retrospective Canadian data collected for the recent United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) global survey on medical exposure. The global survey included three modality categories: diagnostic and interventional radiology, nuclear medicine, and radiotherapy and reports the total number of devices, physicians, examinations, and procedures. Due to the inability to collect high-quality dose data from Canadian sources, the average doses for specific examinations and treatments were estimated using internationally pooled data. The total annual per capita dose from medical exposures was determined to be 1.56 mSv, excluding radiotherapy, resulting in approximately 47% of all radiation doses received by Canadians, compared to natural, industrial, and consumer product sources. This assessment of Canadian medical radiation exposures contributes to global improvement of patient protection, helps establish trends, and identifies where Canadian data collection is lacking, particularly dose data.
The Canadian Nuclear Safety Commission (CNSC) is Canada's nuclear regulatory body responsible for regulating the development, production, and use of nuclear energy and the production, possession, and use of nuclear substances. The CNSC achieves this through a highly regimented licensing process for activities under its mandate that includes engagement with the public and Indigenous Nations and communities who may be potentially affected by the activity to be licenced. This engagement is needed to disseminate objective scientific and technical information and ensure confidence in the regulatory competence of the CNSC. The risk of receiving unwanted exposures from licenced activities and how that exposure would impact a population's health, quality of life, and way of life are among the concerns routinely communicated to the CNSC during engagement. The CNSC typically addresses such concerns through the conveyance of anticipated doses, how those anticipated doses adhere to regulatory criteria, and how those anticipated doses compare to other more commonplace exposures such as from medical procedures. This article explores the disability adjusted life year (DALY) as a potential metric for improving existing radiological risk communication. The DALY is used in public health to quantify a population's burden of disease in terms of years of healthy life lost. Radiation exposure can be potentially included as one of many risk factors that already impact a population's health. In doing so, a more intuitive understanding of radiation risk and how it will impact a population's quality of life may be achieved.
The City of Toronto (Ontario) is Canada's largest urban area in population and areal extent. As a result, elevated activity from urban, industrial, and transportation sectors has increased atmospheric carbon-12 (12C) and carbon-13 (13C) from fossil fuel combustion. Excess 12C and 13C mask natural levels of atmospheric carbon-14 (14C), a phenomenon known as the Suess Effect. Consequently, measurements of atmospheric 14C can be used to quantify anthropogenic fossil fuel contributions. With southern Ontario having an air sampler run by Environment and Climate Change Canada (ECCC) in northern Toronto, there is opportunity to expand our understanding of the atmospheric carbon inventory. Using dendrochronological methods, tree-ring 14C measurements were obtained and compared with background 14C levels to assess urban 14C-depletion across Toronto via six trees representing different urban microclimates. One tree located near the ECCC air sampler closely tracked measured atmospheric 14C levels (Spearman's rho=0.93). While most samples analyzed were 14C-depleted, some years also experienced 14C-enrichment due to elevated 14C emissions from the Pickering Nuclear Generating Station. Trees located in urban parks recorded 14C levels closer to background levels. In general, tree rings effectively record 14C variations, reflecting both fossil fuel and nuclear contributions. Meteorological analysis indicates that proximity to the Pickering Nuclear Generating Station and lake-influenced air masses affects 14C uptake, suggesting that Toronto's atmospheric carbon inventory is spatially complex and that urban sampling sites must be evaluated individually.
Copper has been selected to provide corrosion resistance for containers that will house spent nuclear fuel in deep geological repositories in Canada and elsewhere. Corrosion estimates generally assume that the pre-emplacement period, and those time periods immediately following emplacement, will result in very minimal corrosion of the copper layer, allowing these periods to be ignored in lifetime total corrosion damage calculations. However, when metallic containers are exposed to moist bentonite buffer components, it is possible that conditions could be favourable for some corrosion to occur, leading to the formation of corrosion damage and oxide coatings that could alter corrosion behaviour later in the repository lifecycle. Here, experiments conducted in high humidity atmospheres (98% relative humidity) with moist (20% gravimetric moisture content), compacted bentonite showed that copper corrosion can be enhanced by bentonite contact. The corrosion rate was found to decrease over time, but the rate was consistently higher in the bentonite exposure conditions. Greater penetration depths were also found in bentonite exposed samples. A high degree of heterogeneity was observed on the samples throughout the exposure, with some areas being nearly completely uncorroded and others having hundreds of nanometers of penetration. This indicates that the pre- and early-emplacement periods may need to be included when considering the total damage of the copper container.
