The analysis of the environmental impact of routine radioactive gaseous releases from operating nuclear power stations is discussed using a radiation dose assessment. This analysis includes a discussion of the origin of radionuclide effluents, a discussion of federal policies, and a calculation of radiation doses to man. A model of estimating the radioactive dose from gaseous effluents from light-water-cooled reactors is described using guidelines described in the Code of Federal Regulations and the Nuclear Regulatory Commission's Regulatory Guides. The environmental impact of these sources is then analyzed using dose rates calculated along critical exposure pathways for various radioactive nuclides. Examples are given using factors that have been heretofore documented in the literature. The major radionuclides in the airborne effluents from a PWR, used as an example are noble gases, H-3, radioiodines, and radioactive particles. The results from the methodologies described in this paper are compared to federal radiation limits.

Call number: LD2668 .T4 1985 S566 / Master of Science

Thesis (MScIng)--University of Stellenbosch, 2004. / ENGLISH ABSTRACT: This study investigates energy generation by large-scale solar tower power plants. The performance characteristics of a so-called reference plant with a 4000 m diameter glass collector roof and a 1500 m high, 160 m diameter tower are determined for a site located in South Africa. The relevant draught and conservation equations are derived, discretized and implemented in a numerical model which solves the equations using speci ed meteorological input data and determines the power delivered by the plant. The power output of a solar tower power plant over a twenty-four hour period is presented. Corresponding temperature distributions in the ground under the collector are shown. Variations in seasonal generation are evaluated and the total annual electrical output is determined. The dependency of the power output on collector diameter and tower height is illustrated, while showing that greater power production can be facilitated by optimizing the roof shape and height. The minor in uence of the tower shadow falling across the collector is evaluated, while the e ect of prevailing winds on the power generated is found to be signi cant. / AFRIKAANSE OPSOMMING: Hierdie studie ondersoek elektrisiteitsopwekking deur grootskaalse sontoringkragstasies. Die uitsetkarakteristieke van 'n sogenaamde verwysings-kragstasie met 'n 4000 m deursnee glas kollektor en 'n 1500 m hoë, 160 m deursnee toring word ondersoek vir 'n spesi eke ligging in Suid-Afrika. Die toepaslike trek- en behoudsvergelykings word afgelei, gediskretiseer en geimplementeer in 'n numeriese rekenaarmodel. Die rekenaarmodel los die betrokke vergelykings op deur gebruik te maak van gespesi seerde meteorologiese invoerdata en bepaal dan die uitset gelewer deur die kragstasie. Die uitset van 'n sontoring-kragstasie oor 'n periode van vier-en-twintig uur word getoon. Ooreenstemmende temperatuurverdelings in die grond onder die kollektor word geïllustreer. Die variasie in seisoenale elektrisiteitsopwekking word ondersoek en die totale jaarlikse elektriese uitset bepaal. Die invloed wat die kragstasie dimensies (kollektor deursnee en toring hoogte) op die uitset het, word bestudeer en resultate getoon. Daar is ook bevind dat verhoogde uitset meegebring kan word deur die vorm en hoogte van die kollektordak te optimeer. Die geringe e ek van die toringskadu op die kollektor word bespreek, terwyl bevind is dat heersende winde 'n beduidende e ek op die kragstasie uitset het.

Thesis (MScEng)--University of Stellenbosch, 2004. / ENGLISH ABSTRACT: Up to this point in time research on the South African solar chimney, proposed for a site in the Northern Cape, comprised of determining the structural integrity of the chimney structure, as well as airflow calculation, finding the optimal shape for the airflow channels. Not much work had been done on the realisation of the foundation of the global structure, i.e. how the cardinal parts are optimized in an integrated system. The inlet guide vanes (IGV's) should be central in such research efforts, being the main support of gravitational and lateral wind load on the chimney structure, as well as its important role in channelling air and creating pre-swirl of the airflow onto the turbine blades. However, little detailed research - research to actually determine and fix the many variables of the IGV's and integration with surrounding parts - had been performed! In this thesis as many of these variables as possible are investigated - ranging from structural integrity with regard to compressive and shear strength through optimizing structure eigenfrequency to economic feasibility. The outcome of this study is conceptual solutions regarding the geometry of the IGV structures in order for it to support the chimney while minimizing material volume. Finite element methods are used to create insight into the behaviour of the IGV's and force transferring structures, incorporating external factors such as lateral wind and gravitational loadsto determine the optimal shape of these structures. This study is valuable for researchers on the solar chimney, serving as a reference from where to design and secure the variables of the global structure, and eventually building the solar chimney. Keywords: Solar chimney, inlet guide vanes, solar power, massive concrete structures, structural realisation, finite element application, structure optimisation. / AFRIKAANSE OPSOMMING: Tot op hede het die navorsing op die Suid Afrikaanse sonskoorsteen, wat beplan word vir konstruksie in die Noordkaap, bestaan uit die bepaling van die integriteit van die struktuur asook lugvloei berekeninge om die optimale vorm van die lugvloei kanale te lewer. Min werk is gedoen om die fondasies van die globale struktuur, dus hoe die kardinale dele geïntegreer is in die gesamentlike sisteem, te ondersoek. Die inlaat lei lemme behoort sentraal te lê in sulke navorsingspogings aangesien dit die hoof ondersteuner en verspreider van gravitasie en laterale windlaste op die skoorsteen struktuur is. Dit speelook 'n integrale rol in die kanalisering van invloeiende lug om dit vooraf 'n vorteks beweging te gee vir 'n optimale invalshoek op die turbine lemme. Min gedetaileerde navorsing - navorsing om die verskeie onbekende faktore rondom die inlaat lei lemme en die omliggende strukture te bepaal - is tot op hede gedoen. Hierdie tesis mik om soveel moontlik van hierdie veranderlikes - wat reik van struktuur integriteit met betrekking tot die samedrukkings- en skuifsterktes in die materiaal tot die eie-frekwensies en ekonomiese vatbaarheid van die struktuur - vas te stel. Die uitkoms van hierdie studie is konseptueie oplossings vir die geometrie van die inlaat lei lem strukture wat terselfdertyd die totale struktuur se materiaal volume minimiseer. Eindige element metodes word gebruik om insig in die gedrag van die inlaat lei lemme en ander strukture wat krag oordra, te genereer. Die metodes inkorporeer soveel as moontlik van die eksterne faktore soos gravitasie en laterale windlas om die optimale geometrie vir die betrokke struktuur te bepaal. Hierdie studie is waardevol vir navorsers oor die sonskoorsteen en dien as 'n bron waaruit verdere ontwerp en die vasstel van veranderlikes in die globale struktuur gedoen kan word met die oog op die uiteindelike daarstelling van 'n sonskoorsteen.

published_or_final_version / Business Administration / Master / Master of Business Administration

An important part of the process of assessing the environmental impacts of coal-fired energy development in the Southwest is the transfer of information between electric utilities, federal agencies, and the interested public. There are, however, several problems associated with the transfer of information among the different groups. The acquisition of factual material on power projects by the interested public, for example, is adversely affected by the sufficiency, convenience, and credibility of present sources. Efforts of electric utilities and federal agencies to effectively communicate impact information are hindered by the inability of existing sources to selectively transfer information and to rapidly transmit information on the cumulative impacts of many combinations of power plants. This research concerns the development and evaluation of a computerized information system designed to selectively transfer information on both the cumulative and individual impacts of several electric generating facilities located in the southwestern United States. The information system incorporates features of management information systems, environmental information systems, and an issue-oriented system developed at The University of Illinois, making it a hybrid system capable of communicating impact information derived from a variety of sources. Specifically, the system is able to either retrieve textual material stored in a base information file or to execute on-line simulation models and routines in order to describe environmental impacts. Interactions with the information system are performed at a remote computer terminal by an information specialist who, with the assistance of supporting documents, helps users select information of interest. Evaluation of the system was carried out by demonstrating it to prospective users from electric utilities, government agencies, and the interested public in Arizona. The response of the users to the system shows that this type of communications technology is a viable means of transmitting environmental information. The results of the evaluation also indicate that the system's usefulness is more likely to depend on its credibility than on its convenience and that computer models are an effective way of describing cumulative impacts caused by a series of power plants.

A dissertation submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, in fulfilment of the requirements of the degree of Master of Science in Electrical Engineering June 2016 / Through the Renewable Energy Independent Power Producer Procurement Program (REIPPPP) the South African government has awarded opportunities for growth of renewable energy through bidding rounds. Round 1 saw a total capacity of 397 MW being awarded to independent power producers (IPP). Subsequently Rounds 2, 3 and 4 each had a total capacity of 333 MW auctioned. The advent of renewables on the market has brought upon its own associated problems with regards to power quality issues and failure of HV equipment. This thesis will address transformer failures that occurred at an onshore wind farm. The nature of the transformer failures suggest transient overvoltages are mainly to blame. A comparison between transformer failures in South African and Brazil suggest a common failure mechanism. The failure starts with an inter-turn insulation failure which propagates to an inter-layer insulation. In worst cases the failure mode results in a puncture through the LV-HV barrier and punctures through the LV winding. An extensive literature review was performed to find appropriate methods to predict and explain the failure mode in wind turbine LV-MV step-up transformers. Of the different models which were reviewed the most notable was the Multi-conductor Transmission Line (MTL) model which was chosen as the preferred model due to its ability to predict the inter-turn/inter-layer voltage stresses. Verification of the developed MTL model by the author was then compared to published results of an MTL model of a disc winding transformer. The results of the comparison revealed a relatively good agreement between the developed model and the published model. The application of the MTL model to represent the voltage stresses in transformer windings was then extended to two specially constructed wind turbine step-up transformer prototypes. The prototypes differed in the winding arrangement of the MV coil. The other used two separate MV coils separated by an oil gap whereas the other had a single MV coil. To validate the model accuracy, a comparison of measured results versus those obtained analytically was done for the two prototypes. The analytical and measured results also had a relatively good agreement for the two prototypes considered. Measurement of switching surges was done on-site at the wind farm to understand the nature of the transients. Using analysis tools such as FFT and frequency domain severity factor it was possible to understand the impact the nature of these transients would pose on the transformer insulation. Different mitigation techniques which can be used to alleviate the transient overvoltages to within safe levels were investigated. The most notable protection device considered was the RL choke device which offered a significant reduction of the pre-strikes and is virtually transparent under power frequency operation. / MT2017

Thesis. 1977. M.S.--Massachusetts Institute of Technology. Dept. of Mechanical Engineering. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Includes bibliographical references. / M.S.

Thesis (Master of Engineering in Electrical Engineering)--Cape Peninsula University of Technology, 2018. / Worldwide a movement is underway to replace the burning of limited fossil fuel reserves for power generation with a cleaner, more efficient, yet still reliable and cost-effective method. Even though renewable technologies are often among the most common proposed, they are still limited by factors such as cost when considering large scale generation. Further requirements for replacing fossil fuel generation methods include the need to provide a continuous and reliable output for base load requirements, which is difficult to guarantee when making use of renewables alone. The proposed alternative is nuclear energy, as it is a reliable and cleaner method of power generation as compared to fossil fuels, capable of providing cost effective energy in the long run. The downside to nuclear energy, however, is the negative perception and general dislike of this method of generation, especially among the public who have been around this technology since its early days of implementation. The aim of this study is, therefore, to inform and prove that nuclear technology has evolved and come a long way since its early days, by making use of advanced technological solutions to address the fears associated with this technology from many years ago. The study further aims to prove that technologies such as advanced safety systems, new generations of reactors, advanced containment structures for both reactors and waste containment, as well as new waste disposal methods, have evolved nuclear energy into a safer and cleaner alternative method of power generation. This is achieved by first considering the origin of the negative perceptions surrounding the technology, and the nuclear accidents of the past, which have greatly influenced opinions about nuclear technology even up until today. After identifying the concerns and fears surrounding nuclear energy, research was conducted concerning how the latest technologies and innovations in safety systems are used to address these concerns, and ultimately eliminate the threats where possible. With the biggest concern identified, namely a core meltdown event leading to the release of radioactive material into the environment, two simulations were conducted to illustrate the unlikelihood of such an event occurring. The purpose of these simulations was, moreover, to illustrate the complexity and reliability of the various safety systems incorporated into the design of a nuclear power plant, preventing such a feared release of radioactivity from occurring. The research also importantly revealed that the dangers and possible threats posed by nuclear technology are often grossly overestimated, as under normal operating conditions a coal power plant, in fact, releases more radiation into the environment than a nuclear power plant. Further research reveals that the feared nuclear waste, produced by the nuclear industry yet regulated and disposed of properly, is only a small fraction of the highly hazardous waste produced on an annual basis worldwide. It is also revealed that in terms of fatalities, fossil fuel generation, on average, is responsible for more deaths annually than the biggest nuclear disasters that have ever occurred. Addressing the fears and concerns surrounding nuclear technology is therefore important, as this valuable resource may otherwise remain under-appreciated and under-utilised because of the misperceptions which currently exist amongst the public. This furthermore results in the unnecessary exhaustion of fossil fuel reserves, and concomitant pollution of the environment – all due to antiquated fears surrounding nuclear power plants.

Prepared for the U.S. Dept. of Energy under Contract no. EX-76-A-01-2295, Task order 37.