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Pickering, Canada

Ontario Power Generation is a public company wholly owned by Government of Ontario. OPG is responsible for approximately 50% of the electricity generation in the Province of Ontario, Canada. Sources of electricity include nuclear, hydroelectric, wind, solar and fossil fuel. Although Ontario has an open electricity market, the provincial government, as OPG's sole shareholder, regulated the price the company receives for its electricity to be less than the market average, in an attempt to stabilize prices. Since 1 April 2008, the company's rates have been regulated by the Ontario Energy Board. Wikipedia.

Zhang Y.,University of Toronto | Mckechnie J.,University of Toronto | Cormier D.,FPInnovations FERIC | Lyng R.,Ontario Power Generation | And 3 more authors.
Environmental Science and Technology

The use of coal is responsible for 1/5 of global greenhouse gas (GHG) emissions. Substitution of coal with biomass fuels is one of a limited set of near-term options to significantly reduce these emissions. We investigate, on a life cycle basis, 100% wood pellet firing and cofiring with coal in two coal generating stations (GS) in Ontario, Canada. GHG and criteria air pollutant emissions are compared with current coal and hypothetical natural gas combined cycle (NGCC) facilities. 100% pellet utilization provides the greatest GHG benefit on a kilowatt-hour basis, reducing emissions by 91% and 78% relative to coal and NGCC systems, respectively. Compared to coal, using 100% pellets reduces NOx emissions by 40-47% and SOx emissionsby 76-81%. At $160/metric ton of pellets and $7/GJ natural gas, either cofiring or NGCC provides the most cost-effective GHG mitigation ($70 and $47/metric ton of CO2 equivalent, respectively). The differences in coal price, electricity generation cost, and emissions at the two GS are responsible for the different options being preferred. A sensitivity analysis on fuel costs reveals considerable overlap in results for all options. A lower pellet price ($100/ metric ton) results in a mitigation cost of $34/metric ton of CO2 equivalent for 10% cofiring at one of the GS. The study results suggest that biomass utilization in coal GS should be considered for its potential to cost-effectively mitigate GHGs from coal-based electricity in the near term. © 2010 American Chemical Society. Source

Creates D.H.,Ontario Power Generation
Journal of Pressure Vessel Technology, Transactions of the ASME

Fatigue evaluation in B31.1 is currently done based on equations 1 and 2 of ASME B31.1-2007 Power Piping, which only considers the displacement load ranges. However, fatigue damage, in addition to displacement load ranges, is occurring in B31.1 piping due to pressure cycling and thermal gradients. To exacerbate this, power plant design pressures and temperatures are rising, new materials are being introduced, pipes and attached components are becoming increasingly thick, and owners are requiring power plants to heat-up and cool-down at faster rates. Also, power plant owners are more and more interested in extending the life of power plants beyond their original design life. This article takes the first step in addressing the pressing need to address this additional fatigue damage by quantifying thermal gradients in the prevalent B31.1 welding end transitions in Fig. 127.4.2, or tapered transition joints (TTJs) in Appendix D, of ASME B31.1-2007 Power Piping by formulae to be able to evaluate their contribution to fatigue (see PVP2009-77148 [A Procedure to Evaluate a B31.1 Welding End Transition Joint to Include the Fatigue Effects of Thermal Gradients for Design and Plant Life Extension]). The disadvantage of this approach is that the conservatisms inherent in the calculations of thermal gradients, as per ASME Section III Subsection NB3600-2007, are also inherent in these calculations and may produce unacceptable results when evaluated as per PVP2009-77148 [A Procedure to Evaluate a B31.1 Welding End Transition Joint to Include the Fatigue Effects of Thermal Gradients for Design and Plant Life Extension]. If the results are unacceptable, it is a warning that something else needs to be done. The advantage of this approach is that it eliminates the need for a computer program to quantify these thermal gradients, a computer program that is not normally accessible to the B31.1 designer anyway. Instead, the formulae use the data that are available to the B31.1 designer, namely, physical geometry, thermal conductivity, and rate of temperature change in the fluid in the pipe. This will further help to preserve the integrity of the piping pressure boundary and, consequently, the safety of personnel in today's power plants and into the future. © 2010 American Society of Mechanical Engineers. Source

Vlaicu D.,Ontario Power Generation
Journal of Pressure Vessel Technology, Transactions of the ASME

A cyclically loaded structure made of elastic-plastic material is considered as an elastic shakedown if plastic straining occurs in the first few cycles and the sequent response is wholly elastic. In this paper, the finite element method is used to develop upper and lower bound limits for the elastic shakedown of structures under periodic loading conditions. Linear methods using elastic compensation approach and the residual stress method derived from Melan's theorem are used to generate the lower bound limit for the shakedown load, while the upper bound is found through a method derived from Koiter's theorem. Furthermore, the results are compared with cycle-by-cycle method based on nonlinear material properties. Copyright © 2010 by ASME. Source

Pratt T.C.,Canadian Department of Fisheries and Oceans | Threader R.W.,Ontario Power Generation
North American Journal of Fisheries Management

Significant declines in the recruitment of American eels Anguilla rostrata to formerly productive habitats in the upper St. Lawrence River and Lake Ontario resulted in the implementation of an experimental conservation stocking program. Nearly 3.8 million American eels (glass eel and elver stages) were stocked during 2006-2009. Our study objectives were to (1) assess the adequacy of sampling procedures for following temporal changes in stocked eel abundance, (2) examine captured eels for evidence of spinal trauma, (3) qualitatively evaluate whether stocked eels would disperse outside of stocking locations, and (4) provide initial data on biological variables describing young stocked yellow eels. Boat electro fishing was successful at capturing all four stocked year-classes, and the densities of stocked eels in the main stocking locations ranged from 25 to 275 eels/ha. Estimated sampling precision ranged from 0.15 to 0.28, and the estimated sample sizes required to detect a 50% change in stocked eel densities ranged from 27 to 112 electro fishing transects depending on location and season. The stocked American eels dispersed throughout Lake Ontario and demonstrated among the fastest recorded growth rates for this species: 60 to 123 mm/year. The first male American eels ever identified in the St. Lawrence River watershed were among the stocked individuals assessed for gender. We conclude that boat electro fishing for yellow American eels has the potential to measure stocking effectiveness along shallow shorelines with limited aquatic vegetation. We also recognize that the ultimate assessment of the conservation stocking experiment will not be made until future studies on the population demographics, migratory behavior, and spawning physiology of stocked American eels are complete. © American Fisheries Society 2011. Source

Yang S.,Ontario Power Generation
Nuclear Engineering and Design

This paper presents a Leak-Before-Break (LBB) analysis of large diameter main steam line pipes (i.e. NPS 28″ and 30″) running from reactor building to main steam balance header in Pickering nuclear plant Unit 1 and Unit 4. Recent development in LBB technology summarized in U.S. Nuclear Regular Commission report NUREG/CR-6765 was adopted. Based on the tiered approach of LBB philosophy, this LBB analysis belongs to level 2 or level 3 LBB analysis. Detailed fracture tolerance analyses and leakage rate calculations were performed. EPFM (elastic plastic fracture mechanics) theory of J-integral, resistance curve versus ductile crack extension was adopted in carrying out all fracture tolerance analyses. Through-wall cracks in axial and circumferential directions on both straight pipes and elbows were postulated and analyzed. The loads applied on the postulated cracked pipes were obtained from detailed piping stress analysis under deadweight load, design pressure, thermal expansion, seismic design based earthquake (DBE) and thrust load due to the opening of relief valves. J-resistance data were derived from the lowest fracture toughness testing data obtained from Ontario Power Generation's PHT (primary heat transport) LBB material testing programs. A margin of 2 on crack size was chosen in establishing maximum allowable crack sizes. Leakage rates were calculated using SQUIRT Windows Version 1.1 program. The fluid inside the main steam line pipes was assumed single phase steam at 100% quality. One tenth of the calculated leakage rates was proposed as the requirement for minimum leakage detection capability. The paper concludes that the absence of through-wall crack larger than 91.16 mm in length should be maintained in order to ensure the structural integrity of large diameter main steam line pipes. In lieu of this crack size requirement, a reliable leakage detection capability which could quantify mass steam leakage rate of 0.01678 kg per second, or volume leakage rate of 1.01 l/min, should be in place. If both of the above two requirements are met, the Leak-Before-Break of these large diameter main steam line pipes is warranted. © 2010 Elsevier B.V. All rights reserved. Source

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