Atomic Energy of Canada Limited (AECL) is a Canadian federal Crown corporation and Canada's largest nuclear science and technology laboratory. AECL developed the CANDU reactor technology starting in the 1950s, and in October 2011 licensed this technology to Candu Energy (a wholly owned subsidiary of SNC-Lavalin).Today AECL develops peaceful applications from nuclear technology through expertise in physics, metallurgy, chemistry, biology and engineering. AECL's activities range from research and development, design and engineering to specialized technology development, waste management and decommissioning. AECL partners with Canadian universities, other Canadian government and private-sector R&D agencies (including Candu Energy), various national laboratories outside Canada, and international agencies such as the IAEA.AECL describes its goal as ensuring that "Canadians and the world receive energy, health, environmental and economic benefits from nuclear science and technology - with confidence that nuclear safety and security are assured".Until October 2011 AECL was also the vendor of CANDU technology, which it had exported worldwide. Throughout the 1960s-2000s AECL marketed and built CANDU facilities in India, South Korea, Argentina, Romania, and the People's Republic of China. It is a member of the World Nuclear Association trade group.In addition, AECL manufactures nuclear medicine radioisotopes for supply to Nordion in Ottawa, Ontario, and is the world's largest supplier of molybdenum-99 for diagnostic tests, and cobalt-60 for cancer therapy.AECL is funded through a combination of federal government appropriations and commercial revenue. In 2009, AECL received CA$651 (equivalent to $779.61 in 2020) million in federal support.[citation needed]In October 2011 the federal government of Canada sold the commercial CANDU design and marketing business of AECL to Candu Energy for CA$15 million (including 15 years worth of royalties, the government could get back as much as CA$285 million). The sale entered the exclusive negotiation stage in February, a month after the other bidder, Bruce Power pulled out). Poor sales and cost overruns (CA$1.2 billion in the last five years) were reasons for the divestment though SNC-Lavalin expects to reverse that trend by focusing on new generation reactors. SNC-Lavalin Nuclear Inc, SNC's nuclear subsidiary is already part of Team CANDU, a group of five companies that manufacture and refurbish the CANDU reactors. The government will continue to own the Chalk River Laboratories (produces isotopes for medical imaging). The transaction puts 800 jobs at risk while improving job security for 1,200 employees. Due to safety concerns many countries are considering thorium nuclear reactors which AECL's CANDU reactors easily convert into (from uranium fuelled). Higher energy yields using thorium as the fuel (1 tonne (0.98 long tons; 1.1 short tons) of thorium produces the same amount of energy as 200 tonnes (200 long tons; 220 short tons) tons of uranium) also makes it more attractive. OMERS has also shown interest in the company.
In this paper, a generalized Lagrange interpolation formula expressed in matrix form is developed to systematically expand a sampled function with enhanced flexibility and computational rigor. The proposed formulation employs appropriate coordinate functions that not only satisfy prescribed boundary conditions but also exploit the symmetry or anti-symmetry inherent in the function under consideration. When such conditions are absent, the coordinate functions naturally degenerate into polynomial bases, thereby reproducing the classical Lagrange interpolation as a special case. The expansion coefficients are efficiently obtained through the collocation method, ensuring numerical simplicity and stability. The matrix-based generalized Lagrange interpolation exhibits substantial versatility beyond traditional interpolation tasks. It can be readily applied to numerical differentiation and integration under both uniform and non-uniform sampling schemes. Moreover, the approach proves useful in solving ordinary differential equations with specified boundary constraints, as well as in problems involving root-finding and extremum detection of functions. Numerical experiments demonstrate the accuracy and robustness of the proposed method, revealing a marked reduction in the Runge phenomenon even when the number of sampling points is limited. The results further indicate that computational efficiency and precision improve progressively as the number of samples increases. Overall, the generalized interpolation framework developed herein provides a unified and reliable computational tool for interpolation, differentiation, integration, and boundary-value problems, thereby offering broad potential for applications in numerical analysis and scientific computing.
Canada has a rich history of nuclear technology development. Since the 1940s, nuclear research infrastructure and facilities, such as National Research Universal (NRU) reactor at Canadian Nuclear Laboratories in Chalk River, Ontario, have played a key role for R D and for building Canadian expertise and competency in nuclear technology. The NRU reactor retired in 2018. Since the needs of stakeholders vary with time, consideration of a new multipurpose research reactor for Canada must contemplate current user input for their requirements. As an early step in such consideration, a systematic approach was employed to engage various national stakeholders from academia, industry, and research organizations, including the government. Several virtual workshops were held, each with a specific theme around utilizations. To provide international context, our workshops also included presentations from leading nuclear laboratories around the world. We provide a summary of Canada's approach and the main findings of this early stakeholder engagement.
Accurate dose calculation in radiotherapy is crucial for effective treatment of cancer while minimizing radiation exposure to normal tissues. In this study, the accuracy of anisotropic analytical algorithm (AAA) in radiotherapy treatment planning systems (RTPSs) for lung cancer is evaluated by comparing calculated and measured dose distributions using CIRS Thorax Phantom (Model No.: 002 LFC, CIRS Inc., Norfolk, VA). Three treatment planning techniques—3D conformal radiation therapy (3D CRT), intensity-modulated radiation therapy (IMRT), and volumetric modulated arc therapy (VMAT)—were compared using two X-ray energies (6 MV and 10 MV). Absolute dosimetry was performed on a one-dimensional (1D) water phantom under standard conditions, and dose delivery was checked using a DOSE-1 reference class electrometer. The percentages of error between calculated and measured doses for 6 MV beams were 0.31% for 3D CRT, 2.52% for IMRT, and 0.15% for VMAT. For 10 MV beams, the errors were 0.21%, 0.26%, and 1.41%, respectively. These results demonstrate strong agreement between calculations and measurements, remaining within the 3% tolerance for the lung region. The causes of differences were inhomogeneity of lung tissue, scatter effects, and limitations of the dose algorithm. High-energy beams (10 MV) with increased scattering affecting dosing precision were seen in this study. Among the three techniques, VMAT and 3D CRT exhibited better agreement with planned doses compared to IMRT. These findings confirm the validity of modern treatment planning algorithms for handling tissue heterogeneity and precise dose delivery in lung cancer radiotherapy.
A new approach to evaluation of the fraction of airborne particles that is responsible for adverse health effects has been developed. In this approach a two-fraction concept for the adverse health effects is proposed. This concept considers aerosol particles in the air, the fraction of particles deposited in the respiratory system (captured by the system) and the fraction of particle accumulated in the body (captured by the body). The latter fraction of airborne particles actually causes the adverse health effects and associated with the health risk. The approach has been applied to workers in crystal glass industry exposed to lead. A size resolved sampling technique was employed to characterize nanoparticles at work places at several plants involved in lead processing. Lead aerosol size distributions were obtained across the entire aerosol particle size range from 1 nm to 30 μm (diameter). Size distributions were used to calculate the total lead intake due to particle deposition in the respiratory system of workers. A bio-kinetic model was employed to evaluate various size fraction contributions to the total blood lead level in workers. A comparison was made between calculated blood lead levels and actual measurements of blood lead levels of workers exposed to atmospheres containing lead. It was found that nanoparticles cause the major health risk due to high deposition efficiency and low clearance rate by the mucociliary escalator.
