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Accuracy Based Generation of Thermodynamic Properties for Light Water in RELAP5-3D

Description: RELAP5-3D interpolates to obtain thermodynamic properties for use in its internal calculations. The accuracy of the interpolation was determined for the original steam tables currently used by the code. This accuracy evaluation showed that the original steam tables are generally detailed enough to allow reasonably accurate interpolations in most areas needed for typical analyses of nuclear reactors cooled by light water. However, there were some regions in which the original steam tables were j… more
Date: September 1, 2010
Creator: Davis, Cliff B.
Partner: UNT Libraries Government Documents Department
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Conservation of Fluid Mass and Energy by RELAP5-3D during a SBLOCA

Description: Mass and energy balances were performed to check the accuracy of RELAP5-3D’s solution during a loss-of-coolant accident initiated by a small break in a typical pressurized water reactor. Mass and energy balances were performed for the combined liquid and gas phases and the gas phase by itself. The analysis showed that RELAP5-3D adequately conserved mass and energy for the combined fluid and the gas phase.
Date: August 1, 2009
Creator: Davis, Cliff B.
Partner: UNT Libraries Government Documents Department
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Improved Accuracy for Two-Phase Downflow Scenarios

Description: Problems have been reported for very high downflows in small and intermediate pipes in the bubbly and slug flow regimes. When the flow rate is near critical, the calculated mass flow rate depends strongly on the flow orientation for small and intermediate pipes, whereas the flow rate is nearly independent of flow direction for large pipes. At very high flow rates, the flow is expected to be nearly homogenous and hence to be nearly independent of flow direction. The flow rates calculated by RELA… more
Date: October 1, 2012
Creator: Davis, Cliff B.
Partner: UNT Libraries Government Documents Department
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Implementation of Molten Salt Properties into RELAP5-3D/ATHENA

Description: Molten salts are being considered as coolants for the Next Generation Nuclear Plant (NGNP) in both the reactor and the heat transport loop between the reactor and the hydrogen production plant because of their superior thermophysical properties compared to helium. Because specific molten salts have not been selected for either application, four separate molten salts were implemented into the RELAP5-3D/ATHENA computer program as working fluids. The implemented salts were LiF-BeF2 in a molar mixt… more
Date: January 1, 2005
Creator: Davis, Cliff
Partner: UNT Libraries Government Documents Department
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Evaluation of Fluid Conduction and Mixing within a Subassembly of the Actinide Burner Test Reactor

Description: The RELAP5-3D code is being considered as a thermal-hydraulic system code to support the development of the sodium-cooled Actinide Burner Test Reactor as part of the Global Nuclear Energy Partnership. An evaluation was performed to determine whether the control system could be used to simulate the effects of non-convective mechanisms of heat transport in the fluid, including axial and radial heat conduction and subchannel mixing, that are not currently represented with internal code models. The… more
Date: September 1, 2007
Creator: Davis, Cliff B.
Partner: UNT Libraries Government Documents Department
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Verification and Validation of Corrected Versions of RELAP5 for ATR Reactivity Analyses

Description: Two versions of the RELAP5 computer code, RELAP5/MOD2.5 and RELAP5/MOD3 Version 3.2.1.2, are used to support safety analyses of the Advanced Test Reactor (ATR). Both versions of RELAP5 contain a point reactor kinetics model that has been used to simulate power excursion transients at the ATR. Errors in the RELAP5 point kinetics model were reported to the RELAP5 code developers in 2007. These errors had the potential to affect reactivity analyses that are part of the ATR’s safety basis. Conseque… more
Date: November 1, 2008
Creator: Davis, Cliff B.
Partner: UNT Libraries Government Documents Department
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Analysis Methods and Desired Outcomes of System Interface Heat Transfer Fluid Requirements and Characteristics Analyses

Description: The interface between the Next Generation Nuclear Plant (NGNP) and the hydrogen-generating process plant will contain an intermediate loop that will transport heat from the NGNP to the process plant. Seven possible configurations for the NGNP primary coolant system and the intermediate heat transport loop were identified. Both helium and liquid salts are being considered as the working fluid in the intermediate heat transport loop. A method was developed to perform thermal-hydraulic evaluations… more
Date: April 1, 2005
Creator: Davis, Cliff B.
Partner: UNT Libraries Government Documents Department
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Recent Heat Transfer Improvements to the RELAP5-3D Code

Description: The heat transfer section of the RELAP5-3D computer program has been recently improved. The improvements are as follows: (1) the general cladding rupture model was modified (more than one heat structure segment connected to the hydrodynamic volume and heat structure geometry’s internal gap pressure), (2) the cladding rupture model was modified for reflood, and (3) the heat transfer minor edits/plots were extended to include radiation/enclosure heat flux and generation (internal heat source).
Date: May 1, 2007
Creator: Riemke, Richard A; Davis, Cliff B & Oh, Chang
Partner: UNT Libraries Government Documents Department
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Overview of the Use of ATHENA for Thermal-Hydraulic Analysis of Systems with Lead-Bismuth Coolant

Description: The INEEL and MIT are investigating the suitability of lead-bismuth cooled fast reactor for producing low-cost electricity as well as for actinide burning. This paper is concerned with the general area of thermal-hydraulics of lead-bismuth cooled reactors. The ATHENA code is being used in the thermal-hydraulic design and analysis of lead-bismuth cooled reactors. The ATHENA code was reviewed to determine its applicability for simulating lead-bismuth cooled reactors. Two modifications were made t… more
Date: April 1, 2000
Creator: Davis, Cliff Bybee & Shieh, Arthur Shan Luk
Partner: UNT Libraries Government Documents Department
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Thermal Response of the Hybrid Loop-Pool Design for Sodium Cooled Faster Reactors

Description: An innovative hybrid loop-pool design for the sodium cooled fast reactor (SFR) has been recently proposed with the primary objective of achieving cost reduction and safety enhancement. With the hybrid loop-pool design, closed primary loops are immersed in a secondary buffer tank. This design takes advantage of features from conventional both pool and loop designs to further improve economics and safety. This paper will briefly introduce the hybrid loop-pool design concept and present the calcul… more
Date: September 1, 2008
Creator: Zhang, Hongbin; Zhao, Haihua & Davis, Cliff
Partner: UNT Libraries Government Documents Department
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RELAP5 Analysis of the Hybrid Loop-Pool Design for Sodium Cooled Fast Reactors

Description: An innovative hybrid loop-pool design for sodium cooled fast reactors (SFR-Hybrid) has been recently proposed. This design takes advantage of the inherent safety of a pool design and the compactness of a loop design to improve economics and safety of SFRs. In the hybrid loop-pool design, primary loops are formed by connecting the reactor outlet plenum (hot pool), intermediate heat exchangers (IHX), primary pumps and the reactor inlet plenum with pipes. The primary loops are immersed in the cold… more
Date: June 1, 2008
Creator: Zhang, Hongbin; Zhao, Haihua & Davis, Cliff
Partner: UNT Libraries Government Documents Department
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Heat Transfer Boundary Conditions in the RELAP5-3D Code

Description: The heat transfer boundary conditions used in the RELAP5-3D computer program have evolved over the years. Currently, RELAP5-3D has the following options for the heat transfer boundary conditions: (a) heat transfer correlation package option, (b) non-convective option (from radiation/conduction enclosure model or symmetry/insulated conditions), and (c) other options (setting the surface temperature to a volume fraction averaged fluid temperature of the boundary volume, obtaining the surface temp… more
Date: May 1, 2008
Creator: Riemke, Richard A.; Davis, Cliff B. & Schultz, Richard R.
Partner: UNT Libraries Government Documents Department
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Recent Hydrodynamics Improvements to the RELAP5-3D Code

Description: The hydrodynamics section of the RELAP5-3D computer program has been recently improved. Changes were made as follows: (1) improved turbine model, (2) spray model for the pressurizer model, (3) feedwater heater model, (4) radiological transport model, (5) improved pump model, and (6) compressor model.
Date: July 1, 2009
Creator: Riemke, Richard A.; Davis, Cliff B. & Schultz, Richard.R.
Partner: UNT Libraries Government Documents Department
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RELAP5-3D Code for Supercritical-Pressure Light-Water-Cooled Reactors

Description: The RELAP5-3D computer program has been improved for analysis of supercritical-pressure, light-water-cooled reactors. Several code modifications were implemented to correct code execution failures. Changes were made to the steam table generation, steam table interpolation, metastable states, interfacial heat transfer coefficients, and transport properties (viscosity and thermal conductivity). The code modifications now allow the code to run slow transients above the critical pressure as well as… more
Date: April 1, 2003
Creator: Riemke, Richard Allan; Davis, Cliff Bybee & Schultz, Richard Raphael
Partner: UNT Libraries Government Documents Department
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Assessment of RELAP5-3D for Analysis of Very High Temperature Gas-Cooled Reactors

Description: The RELAP5-3D© computer code is being improved for the analysis of very high temperature gas-cooled reactors. Diffusion and natural circulation can be important phenomena in gas-cooled reactors following a loss-of-coolant accident. Recent improvements to the code include the addition of models that simulate pressure loss across a pebble bed and molecular diffusion. These models were assessed using experimental data. The diffusion model was assessed using data from inverted U-tube experiments. T… more
Date: October 1, 2005
Creator: Oh, Chang; Siefken, Larry & Davis, Cliff
Partner: UNT Libraries Government Documents Department
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Thermal-Hydraulic Analyses Of The LS-VHTR

Description: Thermal-hydraulic analyses were performed to evaluate the safety characteristics of the Liquid-Salt-Cooled Very High-Temperature Reactor (LS-VHTR). A one-dimensional model of the LS-VHTR was developed using the RELAP5-3D computer program. The thermal calculations from the one-dimensional model of a fuel block were benchmarked against a multi-dimensional finite element model. The RELAP5-3D model was used to simulate a transient initiated by loss of forced convection in which the Reactor Vessel A… more
Date: June 1, 2006
Creator: Davis, Cliff B. & Hawkes, Grant L.
Partner: UNT Libraries Government Documents Department
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RELAP5-3D Compressor Model

Description: A compressor model has been implemented in the RELAP5-3D© code. The model is similar to that of the existing pump model, and performs the same function on a gas as the pump performs on a single-phase or two-phase fluid. The compressor component consists of an inlet junction and a control volume, and optionally, an outlet junction. This feature permits cascading compressor components in series. The equations describing the physics of the compressor are derived from first principles. These equati… more
Date: June 1, 2005
Creator: Fisher, James E.; Davis, Cliff B. & Weaver, Walter L.
Partner: UNT Libraries Government Documents Department
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RCCS Experiments and Validation for High Temperature Gas-Cooled Reactor

Description: A reactor cavity cooling system (RCCS), an air-cooled helical coil RCCS unit immersed in the water pool, was proposed to overcome the disadvantages of the weak cooling ability of air-cooled RCCS and the complex structure of water-cooled RCCS for the high temperature gas-cooled reactor (HTGR). An experimental apparatus was constructed to investigate the various heat transfer phenomena in the water pool type RCCS, such as the natural convection of air inside the cavity, radiation in the cavity, t… more
Date: September 1, 2007
Creator: Oh, Chang; Davis, Cliff & Park, Goon C.
Partner: UNT Libraries Government Documents Department
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A Technique for Dynamic Corrosion Testing in Liquid Lead Alloys

Description: An experimental apparatus for the investigation of the flow-assisted dissolution and precipitation (corrosion) of potential fuel cladding and structural materials to be used in liquid lead alloy cooled reactors has been designed. This experimental project is part of a larger research effort between Idaho National Engineering and Environmental Laboratory (INEEL) and Massachusetts Institute of Technology to investigate the suitability of lead, lead-bismuth, and other lead alloys for cooling fast … more
Date: April 1, 2001
Creator: Loewen, Eric Paul; Davis, Cliff Bybee & Mac Donald, Philip Elsworth
Partner: UNT Libraries Government Documents Department
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Development of Safety Analysis Codes and Experimental Validation for a Very High Temperature Gas-Cooled Reactor

Description: The very high temperature gas-cooled reactors (VHTGRs) are those concepts that have average coolant temperatures above 900 degrees C or operational fuel temperatures above 1250 degrees C. These concepts provide the potential for increased energy conversion efficiency and for high-temperature process heat application in addition to power generation and nuclear hydrogen generation. While all the High Temperature Gas Cooled Reactor (HTGR) concepts have sufficiently high temperatures to support pro… more
Date: November 1, 2004
Creator: Chang, H. Oh; Davis, Cliff & Moore, Richard
Partner: UNT Libraries Government Documents Department
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A Parametric Study of the Thermal-Hydraulic Response of Supercritical Light Water Reactors During Loss-of-Feedwater and Turbine-Trip Events

Description: The Idaho National Engineering and Environmental Laboratory in investigating the feasibility of supercritical light water reactors for low-cost electric power production through a Nuclear Energy Research Initiative Project sponsored by the United State Department of Energy. The project is evaluating a variety of technical issues related to the fuel and reactor design, material corrosion, and safety characteristics. This paper presents the results of parametric calculations using the RELAP5 comp… more
Date: September 1, 2003
Creator: Davis, Cliff B.; Buongiorno, Jacopo & MacDonald, Philip E.
Partner: UNT Libraries Government Documents Department
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Advanced Intermediate Heat Transport Loop Design Configurations for Hydrogen Production Using High Temperature Nuclear Reactors

Description: The US Department of Energy is investigating the use of high-temperature nuclear reactors to produce hydrogen using either thermochemical cycles or high-temperature electrolysis. Although the hydrogen production processes are in an early stage of development, coupling either of these processes to the high-temperature reactor requires both efficient heat transfer and adequate separation of the facilities to assure that off-normal events in the production facility do not impact the nuclear power … more
Date: November 1, 2005
Creator: Oh, Chang; Davis, Cliff; Barner, Rober & Pickard, Paul
Partner: UNT Libraries Government Documents Department
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Thermal Hydraulic Analysis of HTGR Coupled with Hydrogen Plant

Description: The US Department of Energy is investigating the use of high-temperature gas-cooled reactors (HTGR) to produce electricity and hydrogen. Although the hydrogen production processes using the nuclear energy are in an early stage of development, coupling hydrogen plant to HTGR requires both efficient heat transfer and adequate separation of the facilities to assure that off-normal events in the production facility do not impact the nuclear plant. In anticipation of the design, development and proc… more
Date: June 1, 2006
Creator: Oh, Chang; Davis, Cliff; Barner, Robert & Pickard, Paul
Partner: UNT Libraries Government Documents Department
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Feasibility Study of Supercritical Light Water Cooled Fast Reactors for Actinide Burning and Electric Power Production

Description: The use of supercritical temperature and pressure light water as the coolant in a direct-cycle nuclear reactor offers potential for considerable plant simplification and consequent capital and O&M cost reduction compared with current light water reactor (LWR) designs. Also, given the thermodynamic conditions of the coolant at the core outlet (i.e. temperature and pressure beyond the water critical point), very high thermal efficiencies of the power conversion cycle are possible (i.e. up to 46%)… more
Date: January 1, 2002
Creator: Mac Donald, Philip Elsworth; Buongiorno, Jacopo; Davis, Cliff Bybee & Weaver, Kevan Dean
Partner: UNT Libraries Government Documents Department
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