Numerical and Experimental Investigation of the Flow in the SNS Jet Flow Target

2015 ◽  
Author(s):  
Charlotte Barbier ◽  
Mark Wendel ◽  
David Felde ◽  
Michael C. Daugherty
Keyword(s):  
Numerical Simulations ◽  
Radiation Transport ◽  
Fluid Dynamic ◽  
National Laboratory ◽  
Jet Flow ◽  
Numerical Approach ◽  
General Purpose ◽  
Temperature Fields ◽  
Beam Power ◽  
Oak Ridge

Computational Fluid Dynamic (CFD) numerical simulations were performed for the flow inside the Spallation Neutron Source jet-flow target vessel at Oak Ridge National Laboratory. Different flow rates and beam conditions were tested to cover all the functioning range of the target, but for brevity, only the nominal case with a mass flow rate of 185 kg/s and a beam power of 1.54MW is presented here. The heat deposition rate from the proton beam was computed using the general-purpose Monte Carlo radiation transport code MCNPX and the commercial CFD code ANSYS-CFX was used to determine the flow velocity in the mercury and the temperature fields in both the mercury and the stainless steel vessel. Boundary conditions, turbulence model and mesh effects are presented in depth. To validate the numerical approach, Particle Imagery Velocimetry (PIV) measurements on a water-loop setup with an acrylic jet-flow target mock-up were performed and compared to the numerical simulations. It was found that a sustained wall jet was developed across the whole length of the vulnerable surface, confirming the good design of the jet-flow target. Overall, good agreements were observed between the experiments and the simulations: the velocity contours and the shape of the recirculation zone near the side baffle are qualitatively similar. However, some differences were also observed that underlines the shortcomings of both the numerical simulations and the experimental measurements.

scholarly journals Modeling of the ORNL PCA Benchmark Using SCALE6.0 Hybrid Deterministic-Stochastic Methodology

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Mario Matijević ◽  
Dubravko Pevec ◽  
Krešimir Trontl
Keyword(s):  
Cross Sections ◽  
Neutron Transport ◽  
National Laboratory ◽  
General Purpose ◽  
Monte Carlo Code ◽  
Oak Ridge ◽  
Benchmark Data ◽  
Selection Of ◽  
Good Agreement ◽  
Reactor Dosimetry

Revised guidelines with the support of computational benchmarks are needed for the regulation of the allowed neutron irradiation to reactor structures during power plant lifetime. Currently, US NRC Regulatory Guide 1.190 is the effective guideline for reactor dosimetry calculations. A well known international shielding database SINBAD contains large selection of models for benchmarking neutron transport methods. In this paper a PCA benchmark has been chosen from SINBAD for qualification of our methodology for pressure vessel neutron fluence calculations, as required by the Regulatory Guide 1.190. The SCALE6.0 code package, developed at Oak Ridge National Laboratory, was used for modeling of the PCA benchmark. The CSAS6 criticality sequence of the SCALE6.0 code package, which includes KENO-VI Monte Carlo code, as well as MAVRIC/Monaco hybrid shielding sequence, was utilized for calculation of equivalent fission fluxes. The shielding analysis was performed using multigroup shielding library v7_200n47g derived from general purpose ENDF/B-VII.0 library. As a source of response functions for reaction rate calculations with MAVRIC we used international reactor dosimetry libraries (IRDF-2002 and IRDF-90.v2) and appropriate cross-sections from transport library v7_200n47g. The comparison of calculational results and benchmark data showed a good agreement of the calculated and measured equivalent fission fluxes.

scholarly journals New search for mirror neutron regeneration

2019 ◽  
Vol 219 ◽  
pp. 07002
Author(s):  
L.J. Broussard ◽  
K.M. Bailey ◽  
W.B. Bailey ◽  
J.L. Barrow ◽  
K. Berry ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
National Laboratory ◽  
General Purpose ◽  
High Flux ◽  
Neutron Lifetime ◽  
Neutron State ◽  
Oak Ridge ◽  
Cold Neutrons

The possibility of relatively fast neutron oscillations into a mirror neutron state is not excluded experimentally when a mirror magnetic field is considered. Direct searches for the disappearance of neutrons into mirror neutrons in a controlled magnetic field have previously been performed using ultracold neutrons, with some anomalous results reported. We describe a technique using cold neutrons to perform a disappearance and regeneration search, which would allow us to unambiguously identify a possible oscillation signal. An experiment using the existing General Purpose-Small Angle Neutron Scattering instrument at the High Flux Isotope Reactor at Oak Ridge National Laboratory will have the sensitivity to fully explore the parameter space of prior ultracold neutron searches and confirm or refute previous claims of observation. This instrument can also conclusively test the validity of recently suggested oscillation-based explanations for the neutron lifetime anomaly.

scholarly journals CG2 general-purpose high-flux SANS instrument at HFIR at Oak Ridge National Laboratory

2008 ◽  
Vol 64 (a1) ◽  
pp. C188-C188
Author(s):  
K.C. Littrell ◽  
W.T. Heller ◽  
V.S. Urban ◽  
G.W. Lynn ◽  
K.M. Atchley ◽  
...  
Keyword(s):  
National Laboratory ◽  
General Purpose ◽  
High Flux ◽  
Oak Ridge ◽  
Oak Ridge National Laboratory ◽  
Sans Instrument

Gas Wall Layer Experiments for SNS Target

2019 ◽  
Author(s):  
Justin R. Weinmeister ◽  
Elvis E. Dominguez-Ontiveros ◽  
Charlotte N. Barbier
Keyword(s):  
Cavitation Erosion ◽  
National Laboratory ◽  
Gas Injection ◽  
Wall Layer ◽  
Test Facility ◽  
Beam Power ◽  
Shear Stresses ◽  
Oak Ridge ◽  
Area Of Interest ◽  
Erosion Mitigation

Abstract The Proton Power Upgrade (PPU) project will increase the proton beam power at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL), requiring new cavitation erosion mitigation techniques for the mercury target vessel. More precisely, a gas wall layer will be injected on the wall surface where heavy cavitation erosion is observed. In this paper, a series of experiments were performed to develop a gas layer on a simplified target geometry. First, experiments in water were used to test a prototype injection strategy in a simplified target nose geometry. Then the experiment was repeated at the Target Test Facility (TTF) at ORNL where mercury wass flowed in the same geometry. Observations showed that gas injection into liquid metal was much more sensitive to flow velocity than in water. Ultimately, the experiments showed the gas injection must be located very close to the area of interest in a non-intrusive configuration to reduce shear stresses in the flow for good gas coverage. This technique will be next implemented in a more prototypical target.

scholarly journals Development of an MCNP6-ANSYS FLUENT Multiphysics Coupling Capability

2016 ◽  
Author(s):  
William Gurecky ◽  
Erich Schneider
Keyword(s):  
State Of The Art ◽  
Radiation Transport ◽  
National Laboratory ◽  
Operating Conditions ◽  
Reactor Physics ◽  
Ansys Fluent ◽  
Oak Ridge ◽  
Deterministic Solution ◽  
Multiphysics Coupling ◽  
Full Power

This work presents a novel core multiphysics coupling method and its application to geometries and thermal hydraulic operating conditions typical of U.S. PWRs. Monte Carlo based radiation transport from the MCNP v6.1.0 package and finite volume thermal hydraulic (TH) packages provided by ANSYS-FLUENT v14.0 are combined to produce results with intra-pin resolved spatial resolution equivalent to state-of-the-art reactor physics and multi-physics suites. The Virtual Environment for Reactor Applications (VERA) whose development is spearheaded at Oak Ridge National Laboratory is one such example package. Results from the MCNP-FLUENT coupling framework are compared to a deterministic solution provided by the MPACT-COBRA-TF (MPACT-CTF) package available in VERA. Comparisons between the MCNP-FLUENT methodology and the MPACT-CTF solutions are provided for a single pin case. Good power and eigenvalue agreement (+/−4%, 352[pcm] respectively) is achieved at hot full power conditions.

A Compact Gas Liquid Separator for the SNS Mercury Process Loop

2021 ◽  
Author(s):  
Charlotte Barbier ◽  
Elvis Dominguez-Ontiveros ◽  
Justin Weinmeister ◽  
Jeremy Slade ◽  
Dustin Ottinger ◽  
...  
Keyword(s):  
Proton Beam ◽  
Pressure Wave ◽  
National Laboratory ◽  
Beam Power ◽  
Target Station ◽  
Pressure Losses ◽  
Oak Ridge ◽  
Helium Bubbles ◽  
Successful Design ◽  
Liquid Separator

Abstract Upgrades at the Spallation Neutron Source (SNS) accelerator at Oak Ridge National Laboratory are underway to double its proton beam power from 1.4 to 2.8 MW. About 2MW will go to the current first station while the rest will go to the future Second Target Station. The increase of beam power to the first target station is especially challenging for its mercury target. When the short proton beam hits the target, strong pressure waves are generated, causing cavitation erosion and challenging stresses for the target's weld regions. SNS has successfully operated reliably at 1.4 MW by mitigating the pressure wave with the injection of small Helium bubbles into the mercury. To operate reliably at 2MW, more gas will be injected into mercury to mitigate the pressure wave further. However, the mercury process loop was not originally designed for gas injection, and the accumulation of gas in the pipes is a concern. Due to space constraints, a custom Gas Liquid Separator (GLS) was designed to fit a 90-degree horizontal elbow space in the SNS mercury loop. Simulations and experiments were performed, and a successful design was developed that has the desired efficiency while keeping the pressure losses acceptable.

Plug-in scripts for EFTEM automation

1996 ◽  
Vol 54 ◽  
pp. 546-547
Author(s):  
N. D. Evans ◽  
M. K. Kundmann
Keyword(s):  
Electron Microscopy ◽  
National Laboratory ◽  
Oak Ridge ◽  
Multiple User ◽  
Transmission Electron ◽  
Short Period ◽  
User Facility ◽  
Instrument Control ◽  
And Control ◽  
Research Equipment

Post-column energy-filtered transmission electron microscopy (EFTEM) is inherently challenging as it requires the researcher to setup, align, and control both the microscope and the energy-filter. The software behind an EFTEM system is therefore critical to efficient, day-to-day application of this technique. This is particularly the case in a multiple-user environment such as at the Shared Research Equipment (SHaRE) User Facility at Oak Ridge National Laboratory. Here, visiting researchers, who may oe unfamiliar with the details of EFTEM, need to accomplish as much as possible in a relatively short period of time.We describe here our work in extending the base software of a commercially available EFTEM system in order to automate and streamline particular EFTEM tasks. The EFTEM system used is a Philips CM30 fitted with a Gatan Imaging Filter (GIF). The base software supplied with this system consists primarily of two Macintosh programs and a collection of add-ons (plug-ins) which provide instrument control, imaging, and data analysis facilities needed to perform EFTEM.

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