Effects of Fission Profiles on the Performance of a U-10Mo Fuel Plate

2019 ◽  
Author(s):  
Hee Seok Roh ◽  
Walid Mohamed ◽  
Hakan Ozaltun
Keyword(s):  
High Performance ◽  
Mechanical Performance ◽  
Experimental Tests ◽  
Operating Conditions ◽  
Fuel Performance ◽  
Element Analysis ◽  
Actual Use ◽  
Enriched Uranium ◽  
Performance Research ◽  
Plate Geometry

Abstract In order to convert the high-performance research reactors from High Enriched Uranium (HEU) to Low Enriched Uranium (LEU) fuel, U-Mo alloy-based fuels in monolithic form have been proposed. These plate-type fuels consist of a high density and low enriched uranium (LEU) foil coated with a diffusion barrier and encapsulated with the aluminum cladding. The performance of the fuel plate has been evaluated by many studies through experimental tests and numerical analyses. When evaluating the performance of a fuel, it is expensive and time-consuming to consider a variation of several parameters, such as fuel plate geometry, material properties, and operating conditions. Fission profile is a critical component of the fuel performance analysis, causing swelling and creep deformation of the fuel plate. Therefore, it can directly affect the stress and strain distributions over the fuel plate. This study aims at investigating the effect of different fission profiles on the thermo-mechanical performance of the fuel plate by finite element analysis. To investigate the effect of fission profile on fuel performance, several different fission profiles were generated and analyzed. The fission profiles were generated based on actual use.

scholarly journals Effects of Plate Curvature on Thermo-Mechanical Performance of U-10Mo Monolithic Fuel Plates

2019 ◽  
Author(s):  
Hakan Ozaltun ◽  
Hee Seok Roh ◽  
Walid Mohamed
Keyword(s):  
High Performance ◽  
Mechanical Response ◽  
Mechanical Performance ◽  
Geometric Parameters ◽  
Temperature Deformation ◽  
Plate Design ◽  
Plate Curvature ◽  
Deformation Stress ◽  
Performance Research ◽  
Plate Geometry

Abstract Monolithic fuel is a candidate fuel form being considered for the conversion of high-performance research reactors. This plate-type fuel consists of a high-density, U-Mo fuel in a monolithic form that is sandwiched between zirconium diffusion barriers, and encapsulated in an aluminum cladding. To date, large number of plates have been irradiated with satisfactory performance. The program is now moving into the qualification phase, a predecessor to the timely conversion of the target reactors. Since each reactor employs distinct fuel plate geometries for various consideration, resulting nearly 50 distinct plate geometries with unique plate design features, a single “generic” plate geometry capturing all of the extremities is not achievable. This limitation consequently requires much more cautious performance evaluations, as thermal and mechanical response of a plate with certain geometry may not be representative for a plate with a different geometry. To evaluate the performance of the plates for various geometric parameters, parametric sensitives studies have been employed. One of the important geometric parameters may have potential effects on the performance is the plate curvature. In this study, curved-plates were parametrically simulated to investigate if this geometric parameter has any effects on overall performance, In particular, radius of curvatures of the plates were varied between the bounding values, and the plates were simulated for comparable irradiation histories. The resulted temperature, deformation, stress-strain results were comparatively evaluated. The results have indicated that preferential deformations occur. This consequently caused shifting of plate centerline on curved plates. The magnitude of centerline shifts increased with increasing plate curvatures.

scholarly journals Innovative and safe supply of fuels for reactors

2020 ◽  
Vol 6 ◽  
pp. 40
Author(s):  
Stéphane Valance ◽  
Bruno Baumeister ◽  
Winfried Petry ◽  
Jan Höglund
Keyword(s):  
Power Plant ◽  
Nuclear Power ◽  
High Performance ◽  
Research Reactor ◽  
Fissile Material ◽  
Nuclear Fuels ◽  
Research Reactors ◽  
Enriched Uranium ◽  
Performance Research ◽  
And Training

Within the Euratom research and training program 2014–2018, three projects aiming at securing the fuel supply for European power and research reactors have been funded. Those three projects address the potential weaknesses – supplier diversity, provision of enriched fissile material – associated with the furbishing of nuclear fuels. First, the ESSANUF project, now terminated, resulted in the design and licensing of a fuel element for VVER-440 nuclear power plant manufactured by Westinghouse. The HERACLES-CP project aimed at preparing the conversion of high performance research reactor to low enriched uranium fuels by exploring fuels based on uranium-molybdenium. Finally, the LEU-FOREvER pursues the work initiated in HERACLES-CP, completing it by an exploration of the high-density silicide fuels, and including the diversification of fuel supplier for soviet designed European medium power research reactor. This paper describes the projects goals, structure and their achievements.

Strengthening of a Bridge Pier with HPC: Modeling of Restrained Shrinkage Cracking

2016 ◽  
Vol 711 ◽  
pp. 1027-1034 ◽  
Author(s):  
Adriano Reggia ◽  
Sara Sgobba ◽  
Fabio Macobatti ◽  
Cristina Zanotti ◽  
Fausto Minelli ◽  
...  
Keyword(s):  
High Performance ◽  
Mechanical Performance ◽  
High Performance Concrete ◽  
Numerical Models ◽  
Experimental Tests ◽  
Concrete Bridges ◽  
Restrained Shrinkage ◽  
Shrinkage Cracking ◽  
Rc Structures ◽  
Restrained Shrinkage Cracking

After more than fifty years from the opening of the largely discussed “Autostrada del Sole” Highway in 1964, the infrastructure system in Italy appears marked by the passing of time, similarly to what observed in several other countries worldwide. The great heterogeneity of the Italian landscape has determined a great variety of construction types, such as large span concrete bridges over the northern rivers and large arch concrete bridges over the valleys of the central region. Increment of vehicle traffic and new seismic regulations are setting new requirements to adapt the existing infrastructure, which should be otherwise replaced. Moreover, reinforced concrete (RC) aging and deterioration have led to structural and material degradation, including severe cracking and corrosion. Specialized materials such as High Performance Concrete (HPC) could represent a viable convenient solution for repairing, strengthening and retrofitting of RC structures as both structural capacity and durability can be refurbished. However, alongside high mechanical performance, HPC is characterized by a high cracking sensitivity at very early age, due to its high stiffness and shrinkage. Restrained shrinkage cracking, particularly significant in repaired structures where the existing concrete generates a considerable restraint against the free movement of the repair material, may represent a limit to the effective application of these materials. For this reason, shrinkage compatibility of HPC with the existing concrete substrate needs to be experimentally and numerically assessed. A study is herein presented where, based on experimental tests, different numerical models are developed and compared to assess and eventually minimize the risk of shrinkage cracking in bridge piers strengthened with HPC.

Effect of Zr Diffusion Barrier Properties on the Irradiation Performance of U-10Mo Monolithic Fuel Plate

2019 ◽  
Author(s):  
Walid Mohamed ◽  
Hakan Ozaltun ◽  
Hee Seok Roh
Keyword(s):  
Mechanical Properties ◽  
Diffusion Barrier ◽  
High Performance ◽  
Mechanical Performance ◽  
Plate Thickness ◽  
Barrier Properties ◽  
Element Analysis ◽  
Uranium Fuel ◽  
High Enrichment ◽  
Irradiation Performance

Abstract The most recent design of U-Mo monolithic fuel as adopted by the U.S. for the conversion of its High Performance Research Reactors (USHPRR) from high enrichment uranium (HEU) to low enrichment uranium fuel (LEU, < 20% U235) consists of a high density (LEU) U-10Mo fuel sandwiched between Zirconium (Zr) diffusion barriers and encapsulated in aluminum (AA6061) cladding. In this work, finite element analysis (FEA) was used to evaluate effect of Zr diffusion barrier properties on the thermal and mechanical performance of a U-10Mo monolithic fuel plate by considering possible variation in thermal and mechanical properties of the Zr diffusion barrier. Possible variation in thermo-mechanical properties of the Zr diffusion barrier were determined and a simulation matrix was designed accordingly. Analyses of simulation results included determination of global peak stresses in the fuel, Zr diffusion barrier, and cladding sections as well as the plate thickness profile at a transverse section toward the top side of the plate. Results showed that variation in yield stress, elastic modulus and thermal conductivity of the Zr diffusion barrier has negligible effect on the thermal and mechanical performance of the monolithic fuel plate. The effect of variation in these properties was found to be limited to the barrier section itself, which may be attributed to the relatively smaller thickness of that section compared to the fuel and cladding sections of the fuel plate.

Robust Design of Bistable Compliant Mechanisms Using the Bistability of a Clamped-Pinned Beam

2008 ◽  
Author(s):  
Young Seok Oh ◽  
Sridhar Kota
Keyword(s):  
Compliant Mechanisms ◽  
Compliant Mechanism ◽  
Experimental Tests ◽  
Operating Conditions ◽  
Loading Conditions ◽  
Element Analysis ◽  
Bistable Behavior ◽  
Stable Position ◽  
Straight Beam ◽  
Free Beam

Our research investigates a new approach to design of bistable compliant mechanisms using the bistability of a clamped-free beam. Bistability plays an important role for a variety of applications since energy is applied only to move the mechanism from one stable position to another and no energy needs to be expended once a stable position is reached. Behavior of a bistable compliant mechanism, in general, is highly non-linear and relies on the buckling phenomenon. Normally, buckling is very sensitive to imperfections in manufacturing processes, operating conditions and boundary conditions. We present a method for designing bistable mechanisms that are robust against such imperfections by utilizing the behavior of a simple clamped-free beam. A solution for large deformation of a simple clamped-free beam is first obtained to study its bistable behavior under various loading conditions. If the load is greater than the critical buckling load, the beam can be deflected not only in the normal direction but also in a ‘reverse-lateral’ (RL) direction. First, an initially straight beam must be bent to a certain curvature under the action of the applied force. In the second loading condition, the partially bent beam is further loaded so that it buckles in the RL direction into a stable position. The magnitude and direction of the forces in both loading conditions that are conducive to bistability are thus determined. A compliant mechanism is then designed such that its output generates desired forces on the beam to deform it in the RL direction. We demonstrate that the RL deformation is less sensitive to the imperfections and ensures bistable behavior. Using clamped-pinned beams, two design examples (symmetric and asymmetric cases) of bistable compliant mechanisms are presented. Results show very good correlation between the finite element analysis and experimental tests on prototypes.

scholarly journals Fuel Swelling and Creep Analysis for a MURR LEU U-10Mo Monolithic Plate

2019 ◽  
Author(s):  
Walid Mohamed ◽  
Hee Seok Roh ◽  
John Stillman ◽  
Erik Wilson
Keyword(s):  
Creep Rate ◽  
High Performance ◽  
Plate Thickness ◽  
High Density ◽  
Maximum Displacement ◽  
Element Analysis ◽  
Maximum Increase ◽  
University Of Missouri ◽  
Rate Analysis ◽  
Enriched Uranium

Abstract U-10Mo monolithic fuel is considered for the conversion of the US High Performance Research and Test Reactors (USHPRR) from high enriched uranium (HEU) to high density low enrichment uranium (LEU) fuel. The monolithic fuel plates are comprised of high density LEU-10Mo fuel core sandwiched between zirconium diffusion barrier interlayers and encapsulated in an aluminum alloy cladding. The conversion of the University of Missouri Research Reactor (MURR), one of the USHPRR fleet, from the use of HEU to LEU is currently in progress. Preliminary safety analysis for the conversion of MURR assumes maximum increase in plate thickness of about 0.1 mm due to irradiation effects. Finite element analysis (FEA) was used to model the thermo-mechanical behavior of a MURR LEU-10Mo monolithic plate under typical irradiation conditions in the LEU core. The maximum increase of the plate thickness was determined considering various combinations of swelling correlations and coefficient of creep rate. Analysis of the displacement profiles showed that maximum displacement along the plate thickness direction occurs at the same location in all cases. For any of the swelling correlations considered in this work, the lowest creep rate coefficient, 5 (× 10−25 cm3/MPa-fission), was found to cause larger outboard displacement. The maximum increase in plate thickness was found not to exceed 0.083 mm with a combination of fuel creep coefficient in the range between 750 and 250 (× 10−25 cm3/MPa-fission) and the the 95% UCL of the most conservative U-10Mo correlation available to describe fuel swelling.

scholarly journals An Enhanced UHPC-Grout Shear Connection for Steel-Concrete Composite Bridges with Precast Decks

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Yongtao Zhang ◽  
Hehui Zheng ◽  
Minghao Tang ◽  
Zhiqi He
Keyword(s):  
High Performance ◽  
Mechanical Performance ◽  
High Performance Concrete ◽  
Frictional Resistance ◽  
Shear Capacity ◽  
Interface Shear ◽  
Element Analysis ◽  
Shear Connection ◽  
Composite Bridges ◽  
Push Out

This article develops an enhanced UHPC-grout shear connection for steel-concrete composite bridges with precast decks. The primary improvement is the use of ultra-high performance concrete (UHPC) as the connection grout. To validate the constructability and the mechanical performance of the new connection, two series of experimental tests (including grouting tests and push-out tests) were conducted. Results from the grouting tests show that both the pressure grouting method and the self-levelling grouting method are applicable to inject the UHPC grout into the channel void of the connection. Results from the push-out tests indicate that the advanced properties of UHPC allow for a significant improvement of the shear resistance of the adhesive connection over traditional cementitious grouts. The ultimate shear capacity of the adhesive connection is controlled by the interface shear strength between the embossed steel and the UHPC grout, with a cohesion value of approximately 5.87 MPa. Meanwhile, the residual frictional resistance can be taken as approximately one-half of the ultimate resistance. The results of the finite-element analysis show that the trilinear model is reasonable to simulate the shear-slip laws of the embossed steel-grout interface and the rough concrete-grout interface.

A Neutronics Feasibility Study of the TRIGA LEU Fuel in the 20MWt NIST Research Reactor

2018 ◽  
Author(s):  
Kyle Anthony Britton ◽  
Zeyun Wu
Keyword(s):  
Feasibility Study ◽  
High Performance ◽  
National Bureau ◽  
Fuel Type ◽  
Research Procedure ◽  
Research Findings ◽  
Enriched Uranium ◽  
Global Threat ◽  
Performance Research ◽  
Neutronic Performance

The National Bureau of Standards reactor (NBSR) at the National Institute of Standards and Technology (NIST) is under conversion from high enriched uranium (HEU) to the low enriched uranium (LEU) schema under the Reduced Enrichment for Research and Test Reactors program (RERTR) as a part of the Global Threat Reduction Initiative (GTRI). The conversion of the high performance research reactors (HPRR) such as NBSR is a challenging task due to the high flux need (2.5 × 1014 n/cm2-s for the NBSR), as well as other neutronics performance characteristics requirements without significant changes to the external geometrical configuration. One fuel candidate, the General Atomics (GA) UZrH LEU fuel, has showed particular promise in this regard. The TRIGA LEU fuel was initially developed in the 1980s with particular considerations for fuel conversion for high power regimes such as high density research and test reactors. This study performs a neutronics feasibility study of the UZrH LEU fuel schema for the NBSR, examining the accountability and sustainability of the TRIGA fuel when applying it to the NBSR conversion. To identify the best option to deploy the TRIGA fuel to NBSR in terms of key neutronic performance characteristic, the study is carried out with various considerations in the fuel dimensions, fuel rod layout configurations, and structure material selections. Monte Carlo based computational model is used to assist and facilitate the research procedure. The research findings in this study will determine the viability of the TRIGA fuel type for the NBSR conversion, and provide supporting data for future investigations on this subject.

Finite Element Analysis Within Component Design Process of Hydraulic Quadruped Robot

2014 ◽  
Author(s):  
Mariapaola D’Imperio ◽  
Ferdinando Cannella ◽  
Claudio Semini ◽  
D. G. Caldwell ◽  
Daniele Catelani ◽  
...  
Keyword(s):  
High Performance ◽  
Virtual Prototyping ◽  
Experimental Tests ◽  
Force Sensor ◽  
Quadruped Robot ◽  
Robot Design ◽  
Element Analysis ◽  
Sensor Optimization ◽  
The Third ◽  
Component Design

The lightweight constructions and components stiffness play an important role in mechanics and in particular in high performance robots. In this paper the Virtual Prototyping Design (VPD) approach for addressing the robot design to this goal is shown. The VPD is applied to three mechanical problems of Walking Hydraulic Robots (WHRs): the first one deals with the leg joint sensitivity analysis; the second one concerns a force sensor optimization while the third one presents the torso structural verification. In all the aforementioned studies the experimental tests and the fitting analyses for model validation were carried out reaching satisfactory results.

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