Atomic Energy of Canada Ltd AECL

Campbell River, Canada

Atomic Energy of Canada Ltd AECL

Campbell River, Canada
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Prudil A.,Royal Military College of Canada | Lewis B.J.,University of Ontario Institute of Technology | Chan P.K.,Royal Military College of Canada | Baschuk J.J.,Atomic Energy of Canada Ltd AECL
Nuclear Engineering and Design | Year: 2014

The Fuel And Sheath modeling Tool (FAST) is a general purpose nuclear fuel performance code. FAST includes models for heat generation and transport, thermal expansion, elastic strain, densification, fission product swelling, cracked pellet, contact, grain growth, fission gas release, gas and coolant pressure and sheath creep. The equations are solved on a two-dimensional (radial-axial) geometry of a fuel pellet and sheath using the Comsol Multiphysics finite-element platform. This paper presents the FAST code for normal operating conditions and results of the proof-of-concept testing against the ELESIM and ELESTRES-IST fuel codes as well as experimental data from seven irradiated fuel elements. In these seven cases, all of the codes were found to under-predict the measured average sheath strains. However, the FAST code was found to under-predict the mid-pellet sheath strains by a smaller margin than the other two codes. A larger data set is required to assess relative accuracy of the codes. © 2014 Elsevier B.V.

Prudil A.,Royal Military College of Canada | Lewis B.J.,University of Ontario Institute of Technology | Chan P.K.,Royal Military College of Canada | Baschuk J.J.,Atomic Energy of Canada Ltd AECL | Wowk D.,Royal Military College of Canada
Nuclear Engineering and Design | Year: 2014

This paper documents the extension of the Fuel And Sheath modeling Tool (FAST) for modeling transient conditions and presents a proof of concept validation exercise. This validation compares the predictions of FAST and ELESTRES/ELOCA fuel performance codes against experimental measurements from a simulated loss of coolant test conducted at Chalk River Laboratories. The comparison includes in reactor measurements of fuel temperature and internal gas pressure along with post irradiation (hot-cell) measurements of cladding deformation and oxidation. The results of this comparison show that the single pellet version of the FAST code was insufficient to fully account for strong axial dependence along an element. This was addressed by modifying the FAST code geometry to allow an arbitrary number of pellets in the fuel-stack. This full element version demonstrated improved agreement with measured cladding deformation, including circumferential ridging effects. © 2014 Elsevier B.V.

Naterer G.F.,Memorial University of Newfoundland | Suppiah S.,Atomic Energy of Canada Ltd AECL | Stolberg L.,Atomic Energy of Canada Ltd AECL | Lewis M.,Argonne National Laboratory | And 10 more authors.
International Journal of Hydrogen Energy | Year: 2014

This paper highlights and discusses the recent advances in thermochemical hydrogen production with the copper-chlorine (Cu-Cl) cycle. Extended operation of HCl/CuCl electrolysis is achieved, and its performance assessment is conducted. Advances in the development of improved electrodes are presented for various electrode materials. Experimental studies for a 300 cm2 electrolytic cell show a stable current density and production at 98% of the theoretical hydrogen production rate. Long term testing of the electrolyzer for over 1600 h also shows a stable cell voltage. Different systems to address integration challenges are also examined for the integration of electrolysis/hydrolysis and thermolysis/electrolysis processes. New results from experiments for CuCl-HCl-H2O and CuCl2-HCl-H2O ternary systems are presented along with solubility data for CuCl in HCl-H 2O mixtures between 298 and 363 K. A parametric study of multi-generation energy systems incorporating the Cu-Cl cycle is presented with an overall energy efficiency as high as 57% and exergy efficiency of hydrogen production up to 90%. © 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights.

Selenium (Se) contamination of aquatic resources and its mitigation is of global concern. Anaerobic bioreactors are the most promising method for treating Se-laden water in end-pit lakes resulting from intensive coal mining and waste rock leachate in the Canadian Rockies. This study assessed the suitability of a bioreactor system to treat non-acidic, coal mine effluent containing 85 μg/L of Se, near Grande Cache, AB, Canada, while making the system as cheap as possible using locally available materials. We successfully used a sediment inoculum from the same end-pit lake as the effluent source to obtain sulfur/Se-reducing bacteria and mixed the inoculum with mulch, manure, gravel, limestone, and bone meal to comprise the ‘active substrate’ for the bioreactors. The anaerobic bioreactors reduced >95 % of the total Se in the inflow water with a flow rate of ≈0.2 m3/h. Se removal was not related to water temperature, which declined from 17 to ≈2 °C in November, suggesting water can be treated regardless of temperature. The use of manure as a bacterial carbon/nitrogen source introduced Escherichia coli into the downstream environment, but after a short elevated concentration, the abundance of E. coli dropped below water quality guidelines. We were able to show that successful Se reduction can be achieved using an anaerobic bioreactor design and locally available material. This design kept the building and maintenance price lower than previous reactors, making the approach promising for larger scale applications and making bioreactors a more cost accessible remediation technology for non-acidic end-pit lakes. © 2014, The Author(s).

Chouhan S.L.,Atomic Energy of Canada Ltd AECL | Scheier N.W.,Atomic Energy of Canada Ltd AECL | Peterson S.-R.,Atomic Energy of Canada
Radioprotection | Year: 2011

CHERPAC is a code developed by AECL to predict the time-dependent concentrations of 25 radionuclides in environmental compartments and the resulting radiation dose (ingestion, inhalation, immersion and groundshine) to humans, following an accidental release to the atmosphere from a nuclear facility. CHERPAC was used to investigate environmental sensitivities in agricultural and forest ecosystems. Given the assumptions in the CHERPAC code, it was concluded that doses to humans from agricultural food products are higher than those from groundshine and forest food products. Doses from agricultural products are highest from radionuclide deposition in summer because all plants are at their peak growth and are ingested fresh after the deposition event. The dose is higher if the deposition occurs in dry conditions rather than during heavy rain, because radionclides adhere better to dry plant leaves. For Cs-137, ingestion dose is higher for adults than other age groups, but for Sr-90 and I-131, ingestion dose is highest for infants. This is due to relative food product concentrations, intake rates and DCFs (dose conversion factors). In the forest ecosystem, adult doses are higher than those for children and infants because of the higher rates of intake by adults of forest food products. © 2011 EDP Sciences.

Riopel R.,Laurentian University | Riopel R.,Atomic Energy of Canada Ltd AECL | Caron F.,Laurentian University | Siemann S.,Laurentian University
Water, Air, and Soil Pollution | Year: 2014

The fate of colored natural organic matter (CNOM) was investigated for a period of 16 months at a municipal wastewater treatment plant of a mid-sized city in Northern Ontario, Canada, using fluorescence spectroscopy. Our objectives were to assess the changes of CNOM at the inlet and outlet of the plant and to determine if these changes were correlated with parameters routinely measured at the plant. The fluorescence signals were spectrally resolved into humic-like, fulvic-like, and protein-like components using a parallel factor analysis (PARAFAC) routine. We found that the signals of the CNOM components in the raw sewage had protein-like characteristics, followed by fulvic-like and humic-like characteristics. Conversely, after treatment, the CNOM signals were dominated by fulvic-like components, followed by approximately equal signals of humic-like and protein-like components. The fluorescence signals were, on average, ∼60 % lower in the effluent for the protein-like components and ∼28 % lower for the humic-like components, suggesting a decomposition of these CNOM materials. The fluorescence signals showed a small apparent increase of fulvic-like components, by ∼4 %, suggesting that the material showing this signal is recalcitrant to decomposition, or it could be potentially produced in the process. We found weak but statistically significant correlations (R 2∈>∈0.3) between the total fluorescence signals and total carbon (TC), the flow rate through the plant, and rainfall in the raw sewage. Similarly, correlations were found between protein-like fluorescence of the protein-like components and total Kjeldahl nitrogen (TKN) and ammonium at the effluent (R 2∈>∈0.3). © 2014 Springer International Publishing Switzerland.

Caron F.,Laurentian University | Siemann S.,Laurentian University | Riopel R.,Laurentian University | Riopel R.,Atomic Energy of Canada Ltd AECL
Journal of Environmental Radioactivity | Year: 2014

Spot samples of shallow groundwaters have been taken between the years 2004 and 2010 near a site formerly used for the dispersal of radioactive liquid wastes. Three sampling points, one clean (upstream), and two downstream of the contamination source, were processed by ultrafiltration (5000Da cut-off) and Solid Phase Extraction (SPE) to determine the association of selected artificial radionuclides (60Co, 137Cs) with Natural Organic Matter (NOM). The last two sampling episodes (2008 and 2010) also benefited from fluorescence analysis to determine the major character of the NOM. The fluorescence signals are reported as humic-like, fulvic-like and protein-like, which are used to characterize the different NOM types. The NOM from the clean site comprised mostly fine material, whereas the colloidal content (retained by ultrafiltration) was higher (e.g., 15-40% of the Total Organic Carbon - TOC). Most of the 137Cs was present in the colloidal fraction, whereas 60Co was found in the filtered fraction. Fluorescence analysis, on the other hand, indicated a contrasting behavior between the clean and contaminated sites, with a dominance of protein-like material, a feature usually associated with human impacts. Finally, SPE removed almost quantitatively the protein-like material (>90%), whereas it removed a much smaller fraction of the 137Cs (<28%). This finding indicates that the 137Cs preferential binding occurs with a fraction other than the protein-like NOM, likely the fulvic-like or humic-like portion. © 2014 Elsevier Ltd.

Mohany A.,Atomic Energy of Canada Ltd AECL | Janzen V.,Atomic Energy of Canada Ltd AECL
American Society of Mechanical Engineers, Pressure Vessels and Piping Division (Publication) PVP | Year: 2010

This paper describes a test program that was developed to measure the dynamic response of a bundle of steam generator U-tubes with Anti-Vibration Bar (AVB) supports, subjected to Freon two-phase cross-flow. The tube bundle has similar geometrical conditions to those expected for future CANDU™ steam generators. Future steam generators will be larger than previous CANDU steam generators, nearly twice the heat transfer area, with significant changes in process conditions in the U-bend region, such as increased steam quality and a broader range of flow velocities. This test program is one of the initiatives that AECL is undertaking to demonstrate that the tube support design for future CANDU steam generators meets the stringent requirements associated with a 60 year lifetime. The main objective of the tests is to address the issue of in- and out-of-plane fluidelastic instability and random turbulent excitation of a U-tube bundle with AVB supports. Details of the test rig, measurement techniques and preliminary instrumentation results are described in the paper. Copyright ©Atomic Energy of Canada Limited, 2009.

Audette-Stuart M.,Atomic Energy of Canada Ltd AECL | Yankovich T.,Atomic Energy of Canada Ltd AECL
Radioprotection | Year: 2011

Adaptive responses were observed using the micronucleus frequency in bullfrog tadpoles. In tanks in which control tadpoles were placed in contact with tadpoles that were previously housed in tritiated water (3.0 × 104Bq/L), the cells from all animals responded as though they were "adapted". This suggests that direct exposure to 3.0 × 10 4Bq/L tritium contributes to an increased resistance to a high dose of radiation in liver cells. It also suggests that being in contact with tadpoles that were previously exposed to 3.0 × 104Bq/L tritium (bystander effect) contributes to an increased resistance to a high dose of radiation in liver cells. In vitro exposures were also conducted using primary cultures of liver cells obtained from an unexposed-non-bystander tadpole. In these control cells, it was observed that exposure to 100? mGy of 60Co gamma radiation (delivered at a dose rate of 5mGy/min) did not affect the micronucleus frequency whereas exposure to 4Gy (delivered at a dose rate of about 10.2Gy/min) increased the micronucleus frequency. Prior exposure to a low dose of 60Co gamma radiation (100 mGy delivered at a dose rate of 5mGy/min) induced an adaptive response, protecting the cells from harm caused by exposure to subsequent high doses of 60Co gamma radiation (4 Gy delivered at a dose rate of about 10.2Gy/min). Using the adaptive response (determined using micronucleus assay) as a biomarker, the data obtained suggest that bystander effects do play a role in wild populations since bullfrog tadpoles that were not exposed to tritium responded like the tadpoles that were directly exposed to tritium after being placed in contact with them. © 2011 EDP Sciences.

Dant J.T.,Purdue University | Richardson R.B.,Atomic Energy of Canada Ltd AECL | Nie L.H.,Purdue University
Physics in Medicine and Biology | Year: 2013

Alpha (α) particles and low-energy beta (β) particles present minimal risk for external exposure. While these particles can induce leukemia and bone cancer due to internal exposure, they can also be beneficial for targeted radiation therapies. In this paper, a trabecular bone model is presented to investigate the radiation dose from bone- and marrow-seeking α and β emitters to different critical compartments (targets) of trabecular bone for different age groups. Two main issues are addressed with Monte Carlo simulations. The first is the absorption fractions (AFs) from bone and marrow to critical targets within the bone for different age groups. The other issue is the application of 223Ra for the radiotherapy treatment of bone metastases. Both a static model and a simulated bone remodeling process are established for trabecular bone. The results show significantly lower AFs from radionuclide sources in the bone volume to the peripheral marrow and the haematopoietic marrow for adults than for newborns and children. The AFs from sources on the bone surface and in the bone marrow to peripheral marrow and haematopoietic marrow also varies for adults and children depending on the energy of the particles. Regarding the use of 223Ra as a radionuclide for the radiotherapy of bone metastases, the simulations show a significantly higher dose from 223Ra and its progeny in forming bone to the target compartment of bone metastases than that from two other more commonly used β-emitting radiopharmaceuticals, 153Sm and 89Sr. There is also a slightly lower dose from 223Ra in forming bone to haematopoietic marrow than that from 153Sm and 89Sr. These results indicate a higher therapy efficiency and lower marrow toxicity from 223Ra and its progeny. In conclusion, age-related changes in bone dimension and cellularity seem to significantly affect the internal dose from α and β emitters in the bone and marrow to critical targets, and 223Ra may be a more efficient radiopharmaceutical for the treatment of bone metastases than 153Sm and 89Sr, if the diffusion of 219Rn to the bone marrow is insignificant. © 2013 Institute of Physics and Engineering in Medicine.

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