Thesis (M.S.)--University of Michigan, 1982.

Graduation date: 1998

Five sediment samples were collected in Bua on the Swedish west coast, near two industries, a paper mill, and a nuclear power plant. The two industries use water in their processes and have long been associated with releases of different substances, such as PCBs, and other chlorinated compounds. The environmental impact by the two industries is believed to be significant. The aim of the project was to examine the sediments close to both the water intake and water output to determine if these industrial activities have in any way changed the composition of the sediments. The sediments were extracted by Soxhlet extraction, followed by a deactivated silica and an acidic silica clean-up and then analysed by using a gas chromatograph coupled to a mass spectrometer, (GC-MS) with electron ionization, EI+, mode used in full scan mode. Each mass spectra were analysed by comparing them to the NIST database from 1998. The results were inconclusive since the peaks were not properly resolved, causing a poor correlation to the NIST database. One batch was specifically analysed for polychlorinated biphenyls (PCB) by using an atmospheric pressure gas chromatograph (APGC) coupled to a mass spectrometer (MS). The PCB analysis provided accurate results, except for the Ringhals intake where the MS became saturated due to the high levels. The river Viskan also showed high levels of PCB. The congener pattern from PCBs found near Ringhals intake resembled an Aroclor pattern from Aroclor 1248. Since the Aroclor pattern is only seen in Ringhals intake, the source is most likely from the small harbour and not from either of the industries.

Thesis (M. Phil.)--University of Hong Kong, 1994. / Includes bibliographical references (leaves 61-64).

No description available.

The long-term operational safety of nuclear power plants is of utmost importance. Seismic isolation has been shown to be effective in reducing the demands on structures in many applications, including nuclear power plants (NPP). Many designs for Generation III+ NPP include a large passive cooling tank as a measure of safety that can be used during power failure. In a large seismic event, the fluid in the tank may be excited, and while the phenomenon of fluid-structure interaction (FSI) has also been studied in the context of base isolated liquid storage tanks, the effect on seismically isolated NPP has not yet been explored. This thesis presents a two-part study on a base isolated NPP with friction pendulum bearings. The first part of the study compares the usage of a linear fluid model to a nonlinear fluid model in determining tank and structural demand parameters. The linear fluid model was found to represent the nonlinear fluid model well for preliminary analysis apart from peak sloshing height, which it consistently underestimated. The second part of the study uses a linear fluid model, an empty tank model and a rigid fluid model to investigate the influence of FSI on the structural response of an isolated NPP compared to a fixed base NPP. In general, the response of a fixed base NPP considering FSI using a linear fluid model can typically be bound by the results assuming an empty tank and assuming a full tank with rigid fluid mass. However, this does not hold for the base isolated NPP, as the peak isolation displacement for an NPP with a linear fluid model at design depth is greater than the peak isolation displacement than the same NPP with an empty tank and with a rigid fluid model. / Thesis / Master of Applied Science (MASc)

In this work, a thermoelectric energy harvester system aimed at harvesting energy for locally powering sensor nodes in nuclear power plant coolant loops has been designed, fabricated and tested. Different mathematical modeling methods have been validated by comparing with experimental results. The model developed by this work has the best accuracy in low temperature range and can be adapted and used with any heat sink, heat pipe, or thermoelectric system, and have proven to provide results closely matching experimental data. Using the models, an optimization of the thermoelectric energy harvesting system has been performed which is applicable to any energy harvester of this variety. With experimental validation, the system is capable of generating sufficient energy to power all the sensors and electronical circuits designed for this application. The effect of gamma radiation on this thermoelectric harvester has also been proved to be small enough through radiation experiment. / Master of Science

The safety of nuclear power plants must be proved, certified and improved. Probabilistic safety assessments are used to estimate the core meltdown risk, by means of sequential analyses of accidents. In order to assess probabilities of the appearance of these sequences, it is necessary to specifically assess probabilities of operation failures accomplished by human operators in a degraded mode. For this purpose, EDF, the French producer of electricity, developed a method that models failures of human actions, by means of a systematic determination of scenarios corresponding to different failure modes. This method, called MERMOS, has been used for several probabilistic safety assessments. In order to increase its reproducibility and to make it more robust, example missions and scenarios will be built. This set of example analyses will be used by experts assessing human reliability: they will develop studies and deduce results more easily. The purpose of this study involves the creation of a methodology to model existing analyses and human reliability data used in MERMOS. This study consists of optimizing a second generation human reliability assessment method in order to overpass its current weaknesses in an operational context by means of the identification of a set of example analyses. / Master of Science

Thesis (M. Phil.)--University of Hong Kong, 1996. / Includes bibliographical references (leaf 245-252).

As a critical public safety-related structure, the long-term integrity of post-tensioned concrete containment buildings (PCCs) is necessary for continued operation of the reactors they house. In 2009, during preparations for a steam generator replacement, extensive subsurface laminar cracking was identified in a portion of the Crystal River 3 (CR3) PCC in Florida, and the plant was permanently shut down in 2013. This study investigates potential contributing factors to the identified cracking with particular focus on the effects of high early-age temperatures on the cracking risk of the concrete, on the development of the concrete properties, and on the late-age structural behavior of the concrete. Two planar, full-scale mock-ups of a portion of the CR3 PCC were constructed and instrumented with temperature and strain gauges to monitor the thermal and mechanical behavior during representative concrete curing and post-tensioning loading. Standard- and match-cured concrete specimens were tested for determination of the time- and temperature-dependent development of thermal and mechanical concrete properties, and hydration parameters were determined for the mock-up cement paste for modeling the heat generation in the concrete. These properties and parameters were utilized in 3D finite element analysis of the mock-ups in COMSOL Multiphysics and compared with experimental results. Non-destructive evaluation via shear wave tomography was conducted on the mock-ups to identify flaws and determine the effectiveness of the methods for identifying delaminations between post-tensioning ducts approximately 10 inches beneath the concrete surface. Though early-age thermal stresses were determined not to have caused cracking in the mock-ups, the high early-age concrete temperatures resulted in decreased late-age mechanical properties that were shown to contribute to greater concrete cracking risk when the mock-up was post-tensioned. Tensile stresses exceeding the tensile strength of the concrete were identified along the post-tensioning ducts when biaxial post-tensioning loads were applied in finite element analysis, but the stresses decreased rapidly with increased distance from the ducts. Through parametric modeling, increasing the tensile strength of the concrete was identified as an effective means of reducing the cracking risk in PCCs. Additionally, relationships between the mechanical properties for the standard- and match-cured specimens were identified that could enable prediction of in-place or match-cured concrete properties based only on the results of tests on fog-cured specimens.