No description available.

<p> Accurate prediction of evaporative losses from light water reactor nuclear power plant (NPP) spent fuel storage pools (SFPs) is important for activities ranging from sizing of water makeup systems during NPP design to predicting the time available to supply emergency makeup water following severe accidents. Existing correlations for predicting evaporation from water surfaces are only optimized for conditions typical of swimming pools. This new approach modeling evaporation as a diffusion process has yielded an evaporation rate model that provided a better fit of published high temperature evaporation data and measurements from two SFPs than other published evaporation correlations. Insights from treating evaporation as a diffusion process include correcting for the effects of air flow and solutes on evaporation rate. An accurate modeling of the effects of air flow on evaporation rate is required to explain the observed temperature data from the Fukushima Daiichi Unit 4 SFP during the 2011 loss of cooling event; the diffusion model of evaporation provides a significantly better fit to this data than existing evaporation models.</p>

Two models were investigated to predict the power and pressure behavior of three liquid Uranium fueled reactors (K sc EWB5, C sc RAC, and S sc ILENE) during fast power excursions. Both models use the point reactor kinetics equations to generate the power and energy distributions in time, and an equilibrium thermodynamic analysis to generate the pressure, temperature, and volume distributions. The first model uses equilibrium thermodynamics to generate an equation of state for bubble formation that is static in bubble radius versus time. The second model uses mass transport theory to generate an equation of state that is dynamic in bubble radius. Simulations of the power excursions were run for both models and the results were compared to the experimental data and to each other. The first model was analyzed by varying the threshold gas mass fraction and the static bubble radius verses a range of step reactivity inputs to determine the effect on peak power and pressure. The second model used a trial and error strategy to determine the adjustable parameters that best fit the experimental data, then was also analyzed against the same ranges of step reactivity input. In the comparison, the dynamic model predicts the power and pressure versus time traces better than the static model.

It is the purpose of this thesis to explore the feasibility of using coated-wire electrodes to measure chelating agent concentration. Chelating agents are often found in radioactive decontamination solutions because they aid in the removal of radionuclides from contaminated surfaces by increasing their solubility. However, this characteristic will also enhance the mobility of the radionuclide and thus its transport out of a waste disposal site. Coated-wire ion selective electrodes, based on a polyvinylchloride membrane using dioctylphthalate as a plasticizer and dinonylnaphthalene-sulfonic acid as a counterion, were constructed for five commonly utilized chelating agents (ethylenediaminetetracetic acid (EDTA), nitrilotriacetic acid (NTA), citric acid, oxalic acid and tartaric acid). The EDTA and NTA electrodes' calibration characteristics exhibited acceptable behavior in pure standard solutions. From data obtained while using the EDTA and NTA electrodes in a cement environment, further research needs to be done in the area of ion interference.

<p> Air bubble injection and subcooled flow boiling experiments have been performed to investigate the liquid flow field and bubble nucleation, growth, and departure, in part to contribute to the DOE Nuclear HUB project, Consortium for Advanced Simulation of Light Water Reactors (CASL). The main objective was to obtain quantitative data and compartmentalize the many different interconnected aspects of the boiling process &mdash; from the channel geometry, to liquid and gas interactions, to underlying heat transfer mechanisms. </p><p> The air bubble injection experiments were performed in annular and rectangular geometries and yielded data on bubble formation and departure from a small hole on the inner tube surface, subsequent motion and deformation of the detached bubbles, and interactions with laminar or turbulent water flow. Instantaneous and ensemble- average liquid velocity profiles have been obtained using a Particle Image Velocimetry technique and a high speed video camera. Reynolds numbers for these works ranged from 1,300 to 7,700.</p><p> Boiling experiments have been performed with subcooled water at atmospheric pres- sure in the same annular channel geometry as the air injection experiments. A second flow loop with a slightly larger annular channel was constructed to perform further boiling experiments at elevated pressures up to 10 bar. High speed video and PIV measurements of turbulent velocity profiles in the presence of small vapor bubbles on the heated rod are presented. The liquid Reynolds number for this set of experiments ranged from 5,460 to 86,000. It was observed that as the vapor bubbles are very small compared to the injected air bubbles, further experiments were performed using a microscopic objective to obtain higher spatial resolution for velocity fields near the heated wall. Multiple correlations for the bubble liftoff diameter, liftoff time and bub- ble history number were evaluated against a number of experimental datasets from previous works, resulting in a new proposed correlations that account for fluid prop- erties that vary with pressure, heat flux, and variations in geometry.</p>

Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2009. / Source: Dissertation Abstracts International, Volume: 70-06, Section: B, page: 3759. Adviser: Roy A. Axford. Includes bibliographical references (leaves 309-311) Available on microfilm from Pro Quest Information and Learning.

The linear Boltzmann equation for the transport of neutral particles is investigated with the objective of generating benchmark-quality calculations for homogeneous infinite media. In all cases, the problems are stationary, of one energy group, and the scattering is both isotropic and anisotropic. In the transport problems considered, the Green's function is generally the quantity of interest. The solution is obtained through the use of the Fourier transform method. The numerical inversions use standard numerical techniques, such as Gauss-Legendre quadrature, summation of infinite series, and Euler-Knopp acceleration. The most basic source of neutral particles is the point-beam source, or Green's function source. The Green's function in an infinite medium with isotropic scattering is treated as explained in chapter two. The Green's function in an infinite medium with anisotropic scattering is treated using two different mathematical methods as explained in chapters three and four. The results for both cases is shown in chapter 5.

Coupling effects between thermal, hydraulic, chemical and mechanical (THCM) processes for rock materials are one of major issues in Geological engineering, Civil engineering, Hydrology, Petroleum engineering, and Environmental engineering. In all of these fields, at least two mechanisms of THCM coupling are considered. For an example, thermal, hydraulic, and mechanical coupling effects are important in Geological engineering and Civil engineering. The THM coupling produces effects on underground structures, since the underground structures are under influences of geothermal gradient, groundwater, gravitational stresses, and tectonic forces. In particular, underground repository of high-level nuclear waste involves all four of the THCM coupling processes. Thermo-hydro-mechanical coupling model for fractured rock media has been developed based on micromechanical fracture model [Kemeny 1991, Kemeny & Cook 1987]. The THM coupling model is able to simulate time- and rate-dependent fracture propagation on rock materials, and quantify characteristics of damage by extensile and shear fracture growth. The THM coupling model can also simulate coupled thermal effects on underground structures such as high-level nuclear waste repository. The results of thermo-mechanical coupling model are used in conducting a risk analysis on the structures. In addition, the THM coupling model is able to investigate variations of fluid flow and hydraulic characteristics on rock materials by measuring coupled anisotropic permeability. Later, effects of chemical coupling on rock materials are investigated and modified in the THM coupling model in order to develop a thermo-hydro-chemo-mechanical coupling model on fractured rocks. The THCM coupling model is compared with thermal, hydraulic, chemical, and mechanical coupling tests conducted at the University of Arizona. The comparison provides a reasonable prediction for the THCM coupling tests on various rock materials. Finally, the THCM coupling model for fractured rocks simulates the underground nuclear waste storage in Yucca Mountain, Nevada, and conducted performance and risk analysis on the repository.

Exergoeconomic analysis of a nuclear power plant is a focus of this dissertation. Specifically, the performance of the Palo Verde Nuclear Power Plant in Arizona is examined. The analysis combines thermodynamic second law exergy analysis with economics in order to assign costs to the loss and destruction of exergy. This work was done entirely with an interacting spreadsheets notebook. The procedures are to first determine conventional energy flow, where the thermodynamic stream state points are calculated automatically. Exergy flow is then evaluated along with destruction and losses. The capital cost and fixed investment rate used for the economics do not apply specifically to the Palo Verde Plant. Exergy costing is done next involving the solution of about 90 equations by matrix inversion. Finally, the analysis assigns cost to the exergy destruction and losses in each component. In this work, the cost of electricity (exergy), including capital cost, leaving the generator came to 38,400 $/hr. The major exergy destruction occurs in the reactor where fission energy transfer is limited by the maximum permissible clad temperature. Exergy destruction costs were: reactor--18,207 $/hr, the low pressure turbine--2,000 $/hr, the condenser--1,700 $/hr, the steam generator--1,200 $/hr. The inclusion of capital cost and O&M are important in new system design assessments. When investigating operational performance, however, these are sunk costs; only fuel cost needs to be considered. The application of a case study is included based on a real modification instituted at Palo Verde to reduce corrosion steam generator problems; the pressure in the steam generator was reduced from 1072 to 980 psi. Exergy destruction costs increased in the low pressure turbine and in the steam generator, but decreased in the reactor vessel and the condenser. The dissertation demonstrates the procedures and tools required for exergoeconomic analysis whether in the evaluation of a new nuclear reactor system concept, or in the assessment of the economic performance in operating plants.

This dissertation presents a comprehensive study of the dynamic response of storage tanks containing high-level radioactive wastes in nuclear facilities. Of the many issues that are peculiar to these systems, four important ones have been studied. Accordingly, the study is presented in four parts. The first part deals with the dynamic response of flexible tanks that are placed inside concrete vaults and are attached to the vaults both at the top and the bottom. The tanks are presumed to be fixed at the base and supported by either a roller or a hinge at the top. The response quantities examined include the natural frequencies of vibration, the hydrodynamic pressures and the induced tank forces. The general trends are established by comparing the response quantities for the top-constrained systems with those for base-excited cantilever systems. The second part deals with the response of rigid and flexible tanks containing stratified liquids. The liquid is considered to be arranged in layers with varying layer thicknesses and mass densities, or to be inhomogeneous with a continuously varying mass density. In addition to the free vibrational sloshing characteristics of the liquid, the responses examined include the vertical displacements at the free surface, and the impulsive and convective components of the hydrodynamic wall pressures and associated tank forces. A simplified analytical procedure that estimates the response quantities for the layered systems from corresponding solutions for homogeneous systems is also presented. The third part presents an exploratory study for assessing the effects of tank-base flexibility on the response of vertically excited liquid storage tanks. A suitable model of the tank-liquid-foundation-soil system is considered, and the natural frequencies, the associated damping ratios and the induced pressures are studied for a wide range of base-flexibility values. The final part estimates the effects induced by the impact of the sloshing liquid on the tank roof. Consideration is given not only to the effects that are induced on the roof but also to the effects that are transferred to the side-wall. Both rectangular and cylindrical systems are considered and the effect of changing the slope of the roof on the induced impact effects is also studied.