There are many types of burnable absorbers currently used in power reactors. They are used to provide reactivity and power peaking control. Westinghouse reactors most commonly use Zirconium Diboride Integral Fuel Burnable Absorbers (ZrB2) while Combustion Engineering reactors most commonly use Erbia Integral Fuel Burnable Absorbers (Erbia) in Combustion Engineering reactors. This paper documents the study to determine the effect of placing Erbia and ZrB2 within a Westinghouse 17×17 fuel assembly, and the effect of these ZrB2/Erbia assemblies on the physics characteristics of a representative Westinghouse 4-loop, 24 month cycle length design. The study consisted first of producing optimal within-assembly burnable absorber configurations where ∼25% of the ZrB2-bearing fuel rods within an assembly were replaced with Erbia-bearing fuel rods. This ratio was selected in order to provide an effective balance between potential peaking factor improvements and the known Erbia disadvantage of increased residual absorber penalty compared with ZrB2. The optimal patterns were selected as the ones that most reduced the assembly-wise cumulative peak-to-average rod power during the depletion compared with existing all-ZrB2 BA configurations with the same BA rod quantity loading. The second part of this study consisted of substituting various quantities of these ZrB2/Erbia feed fuel assemblies in a representative Westinghouse 4-loop, 24 month cycle core design to study the effect on power peaking factors, moderator temperature coefficient (MTC), and cycle length.
Abstract In the current economical market, sustaining a great level of process and company protection is a serious apprehension. Makers can reduce expenses by diminishing destruction to apparatus and exterminating incidents that affect individuals and the atmosphere. Oil and gas industries in recent times have need to meet the challenges with alternative resources being explored by the human mankind. That mandates for producing oil and gas with zero losses. One of the major contributing factors that accounts for increase in cost of production are fires. Fires in oil and gas industries can be mitigated if the potential threats and foreseen consequences are known to the operators. Fire Dynamics Simulator (FDS) software is an appropriate tool that should be implemented at project planning stage by the designers and it should be a part of mandatory requirement implied at approval stage of an oil and gas project. This paper analyzes risks of fire whirl when it is occurred at oil and gas platforms. The study hopes to show how fire patterns are influenced by circulation of air. The fire whirl process over liquid fuel is simulated using FDS, Which produces the development of fire and the change of the radiation intensity and flame height in the case of fire whirl. Also, consequences of fire and wind interaction are considered in this paper. The study results provide reference data and theoretical guidance for fire protection design and firefighting tactics in case of fire whirl. In addition, findings of this study will deliver an optimal safe design for oil and gas facilities.
This document constitutes Volume 1 of the Final Report of a three-year study supported by the special Research Grant Program for Nuclear Energy Research set up by the US Department of Energy. The original motivation for the work was to provide a fast and accurate computer program for the analysis of transients in heavy water or graphite-moderated reactors being considered as candidates for the New Production Reactor. Thus, part of the funding was by way of pass-through money from the Savannah River Laboratory. With this intent in mind, a three-dimensional (Hex-Z), general-energy-group transient, nodal code was created, programmed, and tested. In order to improve accuracy, correction terms, called {open_quotes}discontinuity factors,{close_quotes} were incorporated into the nodal equations. Ideal values of these factors force the nodal equations to provide node-integrated reaction rates and leakage rates across nodal surfaces that match exactly those edited from a more exact reference calculation. Since the exact reference solution is needed to compute the ideal discontinuity factors, the fact that they result in exact nodal equations would be of little practical interest were it not that approximate discontinuity factors, found at a greatly reduced cost, often yield very accurate results. For example, for light-water reactors, discontinuity factors found from two-dimensional, fine-mesh, multigroup transport solutions for two-dimensional cuts of a fuel assembly provide very accurate predictions of three-dimensional, full-core power distributions. The present document (volume 1) deals primarily with the specification, programming and testing of the three-dimensional, Hex-Z computer program. The program solves both the static (eigenvalue) and transient, general-energy-group, nodal equations corrected by user-supplied discontinuity factors.
Hexagonal nodal methods have gone through much progress now that computer codes based on these methods have substantially improved in performance and reached the same level of accuracy and computational efficiency as the square nodal codes. This development necessitated the use of good and reliable reference solutions to a variety of benchmark problems in order to adequately assess the performance of the newly developed family of codes. This paper is a step on providing documented benchmark problem reference solutions which are generated by the widely accepted and well established finite difference code DEF3D-FD. Two and three dimensional problems for a variety of hexagonal cores, including pressurized light water VVER-1000 and VVER-440 reactor cores as well as a heavy water reactor core were analyzed using very fine mesh spacings. Proper extrapolation was performed to determine reference eigenvalues and power distributions for the benchmark problems. These benchmark problems have been used to qualify the accuracy of Westinghouse advanced nodal code for hexagonal cores, ANC-H.
Idaho National Laboratory in collaboration with Argonne National Laboratory has evaluated technology options for a new fast spectrum reactor to meet the fast-spectrum irradiation requirements for the USDOE Generation IV (Gen IV) and Advanced Fuel Cycle Initiative (AFCI) programs. The US currently has no capability for irradiation testing of large volumes of fuels or materials in a fast-spectrum reactor required to support the development of Gen IV fast reactor systems or to demonstrate actinide burning, a key element of the AFCI program. The technologies evaluated and the process used to select options for a fast irradiation test reactor (FITR) for further evaluation to support these programmatic objectives are outlined in this paper.
Expansion of domestic use of nuclear power to provide energy security and environmental sustainability requires minimization of the nuclear waste. To achieve this goal in the short term, transmutation of transuranic (TRU) elements in COmbined Non-Fertile and UO2 (CONFU) Generation-III pressurized water reactor (PWR) assemblies is evaluated. These assemblies are composed of a mix of standard UO2 fuel pins and pins made of recycled TRU in an inert matrix and are designed to fit in currently deployed PWRs. Previous studies have shown the feasibility of a CONFU-Equilibrium (CONFU-E) assembly design with a net TRU balance between production and destruction and a CONFU-Burndown (CONFU-B) assembly design with net destruction of TRU coming from several reactors. In this paper, a CONFU-self-Contained (CONFU-C) assembly is shown to achieve net TRU destruction in a self-contained TRU multirecycling system. Both the CONFU-B and CONFU-C designs are presented in this paper in detail.For these designs a detailed assembly-level neutronic analysis has been performed using CASMO-4 to investigate cycle length, TRU management performance, and key reactor reactivity parameters, along with detailed intraassembly power peaking factors (IAPPFs). Various fuel mixing schemes and cooling times were evaluated. Using the IAPPF results, a full core thermal-hydraulic analysis using VIPRE was performed to validate thermal margins, and a loss-of-coolant-accident event was assessed using RELAP5. Based on the TRU management characteristics of these designs, metrics were developed to reflect the material handling difficulties of the multirecycled fuel, along with its repository impact. These parameters were compared to a standard once-through UO2 cycle, along with other Pu or TRU multirecycling schemes [mixed oxide with enriched uranium (MOX-UE) and COmbustible Recyclage A ILot (CORAIL)]. Finally, an economic analysis has been conducted to compare the fuel cycle cost (FCC) associated with these designs.TRU management results of CONFU-B and CONFU-C showed a net TRU destruction of 2 to 20 kg/TW·h(electric) generated, with an FCC of 12 to 15 mills/kW·h(electric), depending on the mixing strategy and cooling time chosen. Reactor control parameters and thermal margins were found to be comparable to an all-UO2 assembly. While both designs offer significant repository benefits, the accumulation of minor actinides may limit the practicality of fuel multirecycling.
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