Cold-neutron tomography of annular flow and functional spacer performance in a model of a boiling water reactor fuel rod bundle

Zboray, Robert; Kickhofel, John; Damsohn, Manuel; Prasser, H.-M.

doi:10.1016/j.nucengdes.2011.06.029

Cited by 26 publications

(20 citation statements)

References 43 publications

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“…It is due to beam refraction as at these low energies the corresponding wave lengths are such that cold neutron show noticeable wave behavior. This effect, as is discussed in Zboray et al (2011a), is most pronounced at the outer surface of the channel wall and does not influence much the LFT determination. Beam starvation artefacts occur typically in the vicinity of highly attenuating structures or regions.…”

Section: Image Artefacts Spectral and Scatter Effectsmentioning

confidence: 74%

“…We have shown previously that the rest of the imaging system (camera ? objective) has significantly lower blur and thus pose no limitation on the spatial resolution in comparison with the aforementioned effects (Zboray et al 2011a). For quantifying the spatial resolution, in Table 1, the full width at half maximum (FWHM) of the line spread function (LSF) of the imaging system is given.…”

Section: The Cold Neutron Imaging Setup At the Icon Beam Linementioning

confidence: 99%

“…The filtering in the FBP procedure is done in the frequency domain using a Hann filter that suppresses higher spatial frequencies decreasing the noise in the reconstructed images and thereby decreases the relative uncertainty of the LFT estimation by about 0.5 % as is shown in Zboray et al (2011a), with respect to using the so-called Ram-Lak filter, which tends to amplify high frequencies and thereby noise. The frequency response of the two filters and their influence on the spectra of the filtered projection are shown in Fig.…”

Section: Image Reconstruction and Qualitymentioning

confidence: 99%

“…It has been shown in Zboray et al (2011a) that the timeaveraged LFT for a fluctuating, wavy liquid film that is always in contact with the channel wall can be calculated as:…”

Section: Determining the Lftmentioning

confidence: 99%

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Measuring liquid film thickness in annular two-phase flows by cold neutron imaging

Zboray

Prasser

2013

Exp Fluids

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An overview of a measurement method for liquid film thickness in annular flows based on cold neutron imaging is given here. Neutron imaging being a nonintrusive, contactless method is attractive option for twophase flow investigations offering an excellent contrast. It can provide with information at a high spatial resolution on the flow structure, like the thickness of the liquid film in annular flows. The method has been optimized, and its performance, regarding bias, statistical accuracy, upper and lower detection limits, has been thoroughly quantified using computational tools and measurement results. The technique has been developed based on nuclear fuel bundle models; however, it is applicable practically to annular flows in any arbitrary flow channel geometry of interest.

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Section: Image Artefacts Spectral and Scatter Effectsmentioning

confidence: 74%

Section: The Cold Neutron Imaging Setup At the Icon Beam Linementioning

confidence: 99%

Section: Image Reconstruction and Qualitymentioning

confidence: 99%

“…It has been shown in Zboray et al (2011a) that the timeaveraged LFT for a fluctuating, wavy liquid film that is always in contact with the channel wall can be calculated as:…”

Section: Determining the Lftmentioning

confidence: 99%

See 2 more Smart Citations

Measuring liquid film thickness in annular two-phase flows by cold neutron imaging

Zboray

Prasser

2013

Exp Fluids

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“…As the interaction of neutrons with matter is fundamentally different from the interaction of X-rays with matter, neutrons allow investigations not feasible with other techniques such as visualization of hydrogen atoms even in operating systems. For instance, Takenaka et al [106] and later Zboray et al [107] investigated the annular flow of coolant liquid as well as the functional performance of a spacer system in a model system for a boiling water nuclear reactor fuel rod bundle using neutron tomography. Such imaging techniques are excellent tools to verify, understand, and optimize liquid flow in new designs.…”

Section: Neutron Radiographymentioning

confidence: 99%

A Review of Neutron Scattering Applications to Nuclear Materials

Vogel

2013

ISRN Materials Science

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The growing demand for electric energy will require expansion of the amount of nuclear power production in many countries of the world. Research and development in this field will continue to grow to further increase safety and efficiency of nuclear power generation. Neutrons are a unique probe for a wide range of problems related to these efforts, ranging from crystal chemistry of nuclear fuels to engineering diffraction on cladding or structural materials used in nuclear reactors. Increased flux at modern neutron sources combined with advanced sample environments allows nowadays, for example, studies of reaction kinetics at operating temperatures in a nuclear reactor. Neutrons provide unique data to benchmark simulations and modeling of crystal structure evolution and thermomechanical treatment. Advances in neutron detection recently opened up new avenues of materials characterization using neutron imaging with unparalleled opportunities especially for nuclear materials, where heavy elements (e.g., uranium) need to be imaged together with light elements (e.g., hydrogen, oxygen). This paper summarizes applications of neutron scattering techniques for nuclear materials. Directions for future research, extending the trends observed over the past decade, are discussed.

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Experimental and numerical study of stratified viscous oil–water flow

et al. 2021

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Stratified two-phase flows of oil and water are important to the energy industry, and models capable of predicting this type of flow are primordial. Many studies focus on fluids with low viscosity, but a high viscosity oil in the mixture significantly changes its behavior. We gathered experimental data of pressure drop, volumetric fractions, and flow-pattern data of a stratified liquid-liquid flow with high viscosity ratio. In addition, a wire-mesh sensor provided tomographic views of the flow. The data were compared with computational fluid dynamics (CFD) models using OpenFOAM and a one-dimensional model. CFD simulations used an interface capturing method, and turbulence damping was introduced to avoid high eddy viscosity at the interface region. Reynolds Average Navier-Stokes and large eddy simulations were used to account for turbulence, and they showed significant differences. The comparisons showed good overall results for pressure drop, volumetric fractions, and phase distributions between CFD and experiments.

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Cold-neutron tomography of annular flow and functional spacer performance in a model of a boiling water reactor fuel rod bundle

Cited by 26 publications

References 43 publications

Measuring liquid film thickness in annular two-phase flows by cold neutron imaging

Measuring liquid film thickness in annular two-phase flows by cold neutron imaging

A Review of Neutron Scattering Applications to Nuclear Materials

Experimental and numerical study of stratified viscous oil–water flow

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