The Liquid-Salt-Cooled Very High-Temperature Reactor (LS-VHTR) was modeled using the neutronics analysis code SCALE6.0 and the thermal-hydraulics and kinetics modeling code RELAP5-3D with objective to devise, analyze, and evaluate the feasibility and stability of a start-up procedure for this reactor using natural circulation of the coolant and under the Loss Of Offsite Power (LOOP) conditions. This Generation IV reactor design has been studied by research facilities worldwide for almost a decade. While neutronics and thermal-hydraulics analyses have been previously performed to show the performance of the reactor during normal operation and for shutdown scenarios, no study has heretofore been published to examine the active or passive start-up of the reactor. The fuel temperature (Doppler) and coolant density coefficient of reactivity of the LS-VHTR were examined using the CSAS6 module of the SCALE6.0 code. Negative Doppler and coolant density feedback coefficients were calculated. Two initial RELAP5 simulations were run to obtain the steady-state conditions of the model and to predict the changes of the thermal-hydraulic parameters during the shutdown of the reactor. Next, a series of step reactivity additions to the core were simulated to determine how much reactivity can be inserted without jeopardizing safety and the stability of the core. Finally, a start-up procedure was developed, and the restart of the reactor with natural convection of the coolant was simulated. The results of the simulations demonstrated the potential of a passive start-up of the LS-VHTR.

Nuclear power plants across the United States are reaching the end of their current operating licenses, forcing decision makers to think about the way forward. As they consider the best alternatives for dealing with aging nuclear plants, it is becoming increasingly important to have an accurate method for calculating the long-term costs of nuclear power plants. This report begins by investigating the methodologies currently used in these calculations. They focus on the uncertainty associated with deregulated electricity markets and can be broken down into two main categories: discounted cash flow and real options analysis. Next the report discusses the limitations of the current methodologies, focusing specifically on those aspects of evaluation that are currently eclipsed by electricity market uncertainty. Finally the report offers recommendations for addressing these limitations and creating a stronger analytical framework for calculating the lifetime cost of nuclear power plants. / text

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Thesis (MTech (Quality))--Cape Peninsula University of Technology, 2011. / This research project in Procurement Quality Engineering was conducted at a Nuclear Power Generation Company in the Western Cape, South Africa. During the past decade, quality management has become increasingly recognised as highly desirable for all organisations at all levels. All organisations, to varied degrees, can benefit from the application of quality management skills in some parts of their daily operations. The research project will investigate the impact or effect of late deliveries of spares on the operational cost of the organisation. The organisation is not aware what impact the delivery of spares has on operating costs. Against the above background, the problem to be researched within the ambit of this dissertation reads as follows: "Poor product and / or service delivery from Vendors and / or Suppliers have an adverse impact on the output of the Procurement Quality Department" .The primary research objectives of this study are the following: ~ To emphasise the importance of quality within the supply chain. ~ To investigate the impact of non-conforming items delivered to a Nuclear Power Plant. ~ To determine measures which can be put in place to improve communication between suppliers, vendors, buyers and procurement quality engineering. ~ To determine or investigate the cost of poor quality in the organisation. ~ To improve the quality of goods and services through the application of a quality management system within the supply chain. The research method used in this research project involved both qualitative and quantitative research processes. Questionnaires and statistical techniques were used to analyse the data, and to draw conclusions and recommend possible areas for improvement. The research methodology falls within the ambit of a case study.