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Highlights • DNS is carried out to analyse the flow and thermal fields in a simplified Pressurized Thermal Shock scenario. • The configuration consists of a square duct that intersects perpendicularly with a rectangular domain. • The thermal field is treated as a passive scalar with the use to iso-flux and isothermal boundary conditions. Abstract Direct numerical simulation (DNS) is carried out using a high order spectral element method in order to analyse the flow and thermal fields in a Pressurized Thermal Shock (PTS) scenario. The adopted configuration is representative of a simplified reactor pressure vessel. It consists of a square duct that intersects perpendicularly with a rectangular vessel (downcomer). Cold water is injected from the square duct. It impinges against the wall of the downcomer that contains water at higher temperature, and a mixing between the cold and hot water occurs in the downcomer. The fluid properties are assumed to be constant; hence the temperature is treated as a passive scalar. A secondary flow inlet in the upper part of the downcomer is used to mimic the effect of density driven flow. The friction Reynolds number in the duct equals to 180, and a unitary Prandtl number of the fluid is used. The thermal field is solved with two types of boundary conditions, i.e. , iso-thermal and adiabatic conditions, which encompass the two extreme scenarios of a conjugate heat transfer problem. A careful meshing strategy is adopted and the mesh resolution is verified a posteriori in order to meet DNS quality. The mean flow and turbulent statistics are analysed first, and a particular attention is devoted to the analysis of the vortical structures at the edges of the duct flow. The instantaneous flow field is then analysed in order to study the turbulent structure and the vorticity field within the impingement region. The mean temperature and the turbulent statistics of the thermal fields are subsequently analysed for both thermal boundary conditions. The case with iso-thermal boundary condition corresponds to the initial phase of the thermal mixing during a PTS scenario. It is characterized by the presence of cold fluid near the impinging wall and pockets of fluid at higher temperature near the exit of the duct. Regions with large temperature fluctuations are observed near the edges of the duct and at the interface between the deflected impinging fluid and the descending fluid in the downcomer. The case with adiabatic boundary condition corresponds to the later stage of the thermal mixing during a PTS scenario in which a thermal equilibrium is reached. For this case, a region with lower temperature is observed in the downcomer within the impinging jet region and in the region below, whereas the fluid at higher temperature remains confined in the remaining part of the downcomer. [ABSTRACT FROM AUTHOR]

In this paper, various aspects relevant for nuclear applications of bare rod bundles in axial turbulent flows are studied by means of numerical simulations. The work first investigates the fluid dynamics properties of the flow field in the narrow gaps between the rigid rods and then it focuses on the study of the dynamics of the vibrations of the flexible rods. A two-rod assembly is examined first; the system consists of two identical rods in turbulent axial water flows with a small pith-to-diameter ratio and a large wall-to-diameter ratio. In the case of rigid rods, it is found that the flow field is characterized by the presence of strong axial flow pulsations in the gap between the rods with a characteristic frequency close to that observed in previous experimental works at a similar Reynolds number. Subsequently, strongly coupled numerical fluid-structure interaction (FSI) simulations are performed in order to study the flow induced vibration (FIV) of the rods. It is found that a buckling of the rods occurs because the fluid in the gaps pushes the rods apart which then undergo sustained vibrations because of the velocity fluctuations. Furthermore, due to the hydrodynamic coupling, the vibrations of the rods are not independent from each other but the system vibrates as a whole, as confirmed by the spectral analysis which shows the existence of a pair of frequencies around each of the natural frequencies of the structure in vacuo. A seven-rod assembly with the same pitch-to-diameter ratio of the two-rod case is then studied. Numerical simulations reveal the presence of strong flow pulsations in the gaps, although the frequency of the pulsations is slightly lower that than observed in the two-rod case. In the numerical FSI simulations, a very complicated rod-to-rod interaction is observed with the appearance of large vibrations and buckling deformation. [ABSTRACT FROM AUTHOR]

A high-order Residual Distribution scheme for the solution of the compressible RANS equations is developed. The one-equation Spalart–Allmaras turbulence model is solved together with the RANS equations as a fully coupled system, in which both the mean flow equations and the turbulence equation are solved with high-order of accuracy. A continuous approximation of the solution is adopted and standard Lagrangian basis functions are used to construct the discrete space. Since viscous terms involve the gradient of the numerical solution which has a discontinuous normal component across the faces of the elements, a continuous approximation of the gradient of the numerical solution is recovered at each degree of freedom of the grid and then interpolated with the same basis functions used for the solution. The non-linear system of equations resulting from the numerical discretization is solved with the non-linear LU-SGS method. Several numerical experiments are performed to verify the accuracy of the numerical method, these are based on both subsonic and transonic flows in two and three spatial dimensions. [ABSTRACT FROM AUTHOR]

A robust and high order accurate Residual Distribution (RD) scheme for the discretization of the steady Navier–Stokes equations is presented. The proposed method is very flexible: it is formulated for unstructured grids, regardless the shape of the elements and the number of spatial dimensions. A continuous approximation of the solution is adopted and standard Lagrangian shape functions are used to construct the discrete space, as in Finite Element methods. The traditional technique for designing RD schemes is adopted: evaluate, for any element, a total residual, split it into nodal residuals sent to the degrees of freedom of the element, solve the non-linear system that has been assembled and then iterate up to convergence. The main issue addressed by the paper is that the technique relies in depth on the continuity of the normal flux across the element boundaries: this is no longer true since the gradient of the state solution appears in the flux, hence continuity is lost when using standard finite element approximations. Naive solution methods lead to very poor accuracy. To cope with the fact that the normal component of the gradient of the numerical solution is discontinuous across the faces of the elements, a continuous approximation of the gradient of the numerical solution is recovered at each degree of freedom of the grid and then interpolated with the same shape functions used for the solution, preserving the optimal accuracy of the method. Linear and non-linear schemes are constructed, and their accuracy is tested with the method of the manufactured solutions. The numerical method is also used for the discretization of smooth and shocked laminar flows in two and three spatial dimensions. [ABSTRACT FROM AUTHOR]

Although proprioceptive impairment is likely to affect in a significant manner the capacity of stroke patients to recover functionality of upper limb, clinical assessment methods currently in use are rather crude, with a low level of reliability and a limited capacity to discriminate the relevant features of this severe deficit. In the present paper, we describe a new technique based on robot technology, with the goal of providing a reliable, accurate, and quantitative evaluation of kinesthetic acuity, which can be integrated in robot therapy. The proposed technique, based on a pulsed assistance paradigm, has been evaluated on a group of healthy subjects. [ABSTRACT FROM PUBLISHER]

This paper deals with the construction of a class of high-order accurate residual distribution schemes for advection-diffusion problems using conformal meshes. The problems considered range from pure diffusion to pure advection. The approximation of the solution is obtained using standard Lagrangian finite elements and the total residual of the problem is constructed taking into account both the advective and the diffusive terms in order to discretize with the same scheme both parts of the governing equation. To cope with the fact that the normal component of the gradient of the numerical solution is discontinuous across the faces of the elements, the gradient of the numerical solution is reconstructed at each degree of freedom of the grid and then interpolated with the same shape functions used for the solution. Linear and nonlinear schemes are constructed and their accuracy is tested with the discretization of advection-diffusion and anisotropic diffusion problems. [ABSTRACT FROM AUTHOR]

Abstract: A numerical scheme is presented for the solution of the compressible Euler equations in both cylindrical and spherical coordinates. The unstructured grid solver is based on a mixed finite volume/finite element approach. Equivalence conditions linking the node-centered finite volume and the linear Lagrangian finite element scheme over unstructured grids are reported and used to devise a common framework for solving the discrete Euler equations in both the cylindrical and the spherical reference systems. Numerical simulations are presented for the explosion and implosion problems with spherical symmetry, which are solved in both the axial–radial cylindrical coordinates and the radial–azimuthal spherical coordinates. Numerical results are found to be in good agreement with one-dimensional simulations over a fine mesh. [Copyright &y& Elsevier]

Abstract: A complete set of equivalence conditions, connecting the node-centered finite volume and the mass-lumped finite element schemes, is derived for the first time for the one-dimensional compressible Euler equations with cylindrical and spherical symmetry. Analytical expressions for the evaluation of the equivalent cell volumes and interface normals in terms of the finite element integrals are presented. Numerical experiments for compressible unsteady flows, including expanding and converging shock problems, are carried out using the new approach and the differences with the results from a finite volume scheme violating the equivalence conditions are discussed. [ABSTRACT FROM AUTHOR]

The effect of prefermentative cold maceration (PCM) on Merlot winemaking was studied in order to evaluate its influence on the content of phenolic and volatile compounds. The results showed that PCM increased the concentration of phenolic compounds in Merlot red wine. This is particularly important for the extraction of anthocyanins, mainly malvidine-3-glucoside, which contributes to the colour stability. PCM also increased the concentration of the volatile compounds, particularly the esters, α-terpineol, geraniol and 2-phenylethanol which are fingerprints for this wine. The application of the cold maceration process proved to be successful. In fact the concentration of the esters responsible for the typical flavour of Merlot increased by more than 20% in the PCM-wine with respect to the traditional wine. [ABSTRACT FROM AUTHOR]

Abstract: In this work several experiments were performed in 50cm3 shaken-tubes, thus allowing methanol to be selected as the most appropriate leaching solvent for alizarin from roots of common madder (Rubia tinctorum). Methanol at 25°C was found to be able to extract not only free alizarin but also its glycosidic forms, thus resulting in an overall alizarin extraction yield of 2.9±0.1gkg−1 of dried material when leaching madder root particles with 100dm3 of methanolkg−1. Further extraction tests using a liquid–solid ratio of 40dm3 kg−1 in a 1-dm3 stirred extractor allowed the production of a methanolic extract, which was then dried under vacuum. The solid residues were re-dissolved in ethanol so as to avoid methanol vapours exhaling from dyeing baths. Dyed standard specimens of raw cotton and wool exhibited almost the same reddish-yellow hue, even if those coloured with the ethanolic extract had a lighter colour intensity and a more pinkish shade than those dyed with Rubia root particles. Whatever the dyeing procedure used, the colour intensity or hue of cotton specimens was found to be brighter or more pinkish than the wool ones. These characteristics were also more evident for the cotton specimens dyed with the ethanolic extract. The fastness properties of dyed cotton and wool specimens were evaluated and it was found that all the dyed specimens were not or just slightly affected by manual washing at 40°C, acid or basic perspiration tests, and it was also found that the resistance to fading of dyed wool specimens was generally greater than that of cotton ones. [Copyright &y& Elsevier]

Matching of donor and recipient for the class I human leukocyte antigen-C (HLA-C)-encoded natural killer (NK) epitopes has been reported to influence stem-cell (SC) graft outcome, but a consistent picture has not yet emerged. We have analyzed transplant outcome in 104 unrelated SC grafts in relation to NK epitope (C1 and C2) matching and donor killer cell immunoglobulin-like receptor (KIR) genotype. NK epitope mismatching in the rejection direction was strongly associated with an increased probability of rejection subsequent to engraftment. The prevalence of grades III–IV acute graft-vs-host disease (GVHD) was significantly higher and occurred significantly earlier when there was NK epitope mismatching in the GVH direction. Higher transplant-related mortality and lower disease-free survival rates were associated with epitope mismatching regardless of the mismatch direction. A greater number of KIR receptors, both activating and inhibitory, in the donor protected against grades III–IV GVHD and improved survival. [ABSTRACT FROM AUTHOR]

HLA allele mismatches will provoke T-cell alloreactivity after allogeneic stem cell transplantation. As donors and recipients are usually HLA matched, the public HLA epitopes that are recognized by natural killer (NK) cells (NK epitopes) are rarely mismatched, and therefore there is rarely potential for NK alloreactivity arising from the absence of ligands for inhibitory killer immunoglobulin-like receptors ( KIR). Transplants using related donors sharing only one haplotype (haploidentical donors) represent a setting in which NK epitopes are often mismatched, thus resulting in the potential for NK alloreactivity. We have analyzed engraftment, acute graft vs host disease (GVHD), leukemia relapse, and survival in 62 haploidentical transplants in relationship with potential NK alloreactivity, inhibitory, and activating KIR genes of class I HLA NK epitopes. Potential NK alloreactivity in the rejection direction was not associated with any outcome variable. Potential NK alloreactivity in the GVHD direction was associated with an increased incidence of severe GVHD and poorer patient survival but not with non-engraftment nor leukemia relapse. A higher number of activating KIR receptors in the genome of the donor was associated with a higher prevalence of GVHD. These results suggest that lack of extensive T-cell depletion in haploidentical transplantation is associated with high GVHD rates and diminishes the benefits of NK-cell alloreactivity. [ABSTRACT FROM AUTHOR]

• FSI simulations are performed to study FIV of nuclear fuel rods. • Two types of rods are considered: 1) bare and 2) wire-wrapped. • The effects of the working fluid on the dynamics of rods is investigated. • Two different bare 7-rod configurations are also studied. In this work, Fluid-Structure Interaction (FSI) simulations are performed to study Flow Induced Vibrations (FIV) of nuclear fuel rods using the commercial code STAR-CCM+. The Navier-Stokes equations are solved on deforming grids with the Arbitrary Eulerian-Lagrangian (ALE) formulation. The finite element method is used to solve the linear elastic problem for the structure. The two solvers are tightly coupled together with the Gauss-Seidel method to solve the FSI problem. The first part of the work focuses on the FIV of a single rod. Two types of rods are considered: 1) a bare rod and 2) a rod with a wire spacer helically wrapped around its external surface. For the case of the bare rod configuration, the effects of the working fluid on the dynamics is investigated and a correlation for the frequencies as function of density is proposed. The second part of the work focuses on the analysis of FIV for two different configurations of bare seven-rod bundle. One of the main features of the considered configurations is the appearance of axial flow fluctuations in the rod gaps due to the velocity difference in the sub-channels between the rods. Therefore, this part of the work focuses on the study of the effect of the velocity pulsations on the vibrations of the rods. [ABSTRACT FROM AUTHOR]

High resolution genotyping of human leukocyte antigen (HLA) class I and II alleles is important for stem cell transplantation, however it is unclear whether polymorphisms outside of exon 2 and 3 are relevant. With the development of Sanger Sequence Based Typing (SSBT) methods, a high degree of polymorphism at the HLA loci has been identified, making allele identification challenging. Allele ambiguities frequently occur because of the inability to set phase and the lack of complete genomic sequences in reference databases. With the introduction of Next Generation Sequencing (NGS), it is now possible to sequence the HLA genes clonally, completely and simultaneously. Using in-house long range PCR-NGS protocols on the Ion PGM, the aim of this study was to confirm and obtain complete gene sequence for submission to the IMGT/HLA database, on samples identified as novel or rare for HLA Class I alleles by traditional short range (exons 2 and 3) SSBT. In addition, the full length sequences generated by NGS were confirmed using the novel full-length, group-specific sequence based typing (SBT) method, which results in hemizygous sequences, developed in Maastricht. For NGS, long range PCR which amplifies the full gene of HLA-A, -B and -C and exon 2 through to exon 3 of HLA Class II genes was performed. Long range amplicons for each individual are pooled for single library preparation using a modified version of the Ion PGM library preparation and 400 bp chemistry sequencing protocol. All data generated was analysed with software provided by Conexio Genomics and Life Technologies. Analysis of NGS-Ion PGM data identified and confirmed HLA Class I novel and rare alleles reported by short range SSBT. Furthermore, the group-specific sequence based typing results also confirmed data obtained by NGS-Ion PGM. In addition, a number of novel polymorphisms, mainly in intronic sequences, were identified by both sequence based typing methods. NGS-Ion PGM sequencing in addition to group-specific sequence based typing allowed the submission of several full length sequences to the IMGT/HLA database. This study shows the strength of NGS as a tool to complete the IMGT/HLA reference database and the continued relevance of SSBT as a reference methodology. This approach is currently been developed and applied to HLA Class II novel and rare alleles. [ABSTRACT FROM AUTHOR]

The aim of this paper was to study the phenolic compounds evolution during the off-vine drying process in chamber at controlled temperature and to assess whether this dehydration technique might be used to avoid strong oxidations. Grapes were placed in perforated plastic boxes inside a chamber; fans were installed to ensure humidity and temperature control. Phenolic compounds were characterized by HPLC. Dehydration was fast and regular. This technique ensures phenols protection, artificially dried grapes maintained a higher phenolic concentration than those just harvested. This grape drying technique may ensure the production of sweet wines in which phenols content is preserved. [ABSTRACT FROM AUTHOR]

We have described previously a novel single-tube polymerase chain reaction (PCR) amplification (STAmp) protocol for the efficient sequencing-based typing (SBT) of human leukocyte antigen (HLA)-DRB1. The PCR amplification mix includes primers to each of seven allele group-sequence motifs. We have applied this principle to the simultaneous SBT of HLA-DRB3, -DRB4, and -DRB5 using locus specific primers. We report here a multicenter international evaluation of the STAmp protocols performed as a component of the 13th International Histocompatibility Workshop. Identical amplification primer mixes, sequencing primers, and DNA were sent to participating laboratories. The primer mixes contained the amplification primers and the PCR buffer. Each laboratory was requested to amplify the DNA with the primer mixes and perform SBT on the resulting PCR protocols, using their own protocols, and return the typing results for analysis. The reported results indicated that the expected sequence could be obtained with a variety of PCR amplification and sequencing platforms and protocols. There were difficulties but these seemed unrelated to STAmp reagents and suggest that optimal SBT results can be obtained if bi-directional sequencing is performed and software is used for sequence verification and editing. This indicates that SBT by STAmp can be applied in many laboratories for high-throughput HLA-DRAB and HLA-DRAB,4,5 SBT. [ABSTRACT FROM AUTHOR]

• The wavelength of the flow pulsations does not depend on the Reynolds number. • The experimental frequency of flow pulsations is correctly captured by the codes. • The results are very sensitive to dimensional tolerances and modelling of the rods. Fluid flows through rod bundles are observed in many nuclear applications, such as in the core of Gen IV liquid metal fast breeder nuclear reactors (LMFBR). One of the main features of this configuration is the appearance of flow fluctuations in the rod gaps due to the velocity difference in the sub-channels between the rods. On one side, these pulsations are beneficial as they enhance the heat exchange between the rods and the fluid. On the other side, the fluid pulsations might induce vibrations of the flexible fuel rods, a mechanism generally referred to as Flow Induced Vibrations (FIV). Over time, this might result in mechanical fatigue of the rods and rod fretting, which eventually can compromise their structural integrity. Within the SESAME framework, a joint work between Delft University of Technology (TU Delft), Ghent University (UGent), and NRG has been carried out with the aim of performing experimental measurements of FIV in a 7-rods bundle and validate numerical simulations against the obtained experimental data. The experiments performed by TU Delft consisted of a gravity-driven flow through a 7-rods, hexagonal bundle with a pitch-to-diameter ratio P / D = 1.11. A section of 200 mm of the central rod was made out of silicone, of which 100 mm were flexible. Flow measurements have been carried out with Laser Doppler Anemometry (LDA) whereas a high-speed camera has measured the vibrations induced on the silicone rod. The numerical simulations made use of the Unsteady Reynolds-averaged Navier-Stokes equations (URANS) approach for the turbulence modelling, and of strongly coupled algorithms for the solution of the fluid-structure interaction (FSI) problems. The measured frequency of the flow pulsations, as well as the mean rod displacement and vibration frequency, have been used to carry out the benchmark. [ABSTRACT FROM AUTHOR]

The article presents a case study of a patient suffering from a long-standing dactylitis-like aspect of the left thumb. It reports that dactylitis is a typical manifestation of spondyloarthropathies and is due to flexor tenosynovitis. Synovitis of the metacarpophalangeal, proximal and distal interphalangeal joints is a facultative condition and extensor tenosynovitis may also be present as an adjunctive sign. Physical examination is sufficient for the diagnosis of dactylitis. The patient had a six-year history of sub continuous arthralgias localized in the peripheral joints, mainly the wrists and ankles.

Background The elderly are characterized by a high prevalence of chronic heart failure (CHF) and frailty, which is a complex interaction of physical, psychological and social impairment. This study aimed to examine the predictive role of frailty on long-term mortality in elderly subjects with CHF. Materials and methods The study assessed long-term mortality after 12-year follow up in 120 subjects with CHF and 1139 subjects without CHF, selected in 1992, from a random sample of the elderly population in the Campania region of Italy. Frailty was assessed according to a ‘Frailty Staging System’. Results Subjects with CHF were prevalently female (60%) and older than 75 years (mean 75·9 ± 6·7); subjects without CHF were prevalently female (56·4%) and younger than 75 years (mean 74·0 ± 6·3). In subjects with and without CHF stratified into classes of frailty there was a statistically significant increase in age, comorbidity, disability and low social support, and a decrease in MMSE score. Moreover, death progressively increased more with frailty in subjects (70·0% to 94·4%, P < 0·03) than in those without (43·8.% to 88·3%, P < 0·0001) CHF. The Kaplan–Meier analysis shows that at 9 years the probability of survival progressively decreased as frailty increased (45·5% to 0%) in subjects with CHF and from 62·8% to 25·9% in subjects without CHF. The Cox regression analysis indicated that frailty is predictive of mortality in the multivariate model adjusted for several variables including sex and age in subjects with and without CHF. Moreover, the analysis showed that frailty is more predictive of mortality in elderly subjects with CHF when it was analyzed either as continuous (1·48 vs. 1·36) or as a dummy (3 vs. 1 = 1·62 vs. 1·24) variable. Conclusions Thus mortality among elderly subjects with or without CHF increases with frailty. Moreover, frailty is more predictive of long-term mortality in elderly subjects with than in those without CHF. Hence, frailty represents a new independent variable for predicting long-term mortality in elderly subjects with CHF. [ABSTRACT FROM AUTHOR]

Abstract: Ischemic preconditioning (IP) has been proposed as an endogenous form of protection against ischemia reperfusion injury. IP, however, does not prevent post-ischemic dysfunction in the aging heart but may be partially corrected by exercise training and food restriction. We investigated the role of exercise training combined with food restriction on restoring IP in the aging heart. Effects of IP against ischemia-reperfusion injury in isolated hearts from adult (A, 6 months old), sedentary ‘ad libitum’ fed (SL), trained ad libitum fed (TL), sedentary food-restricted (SR), trained- and food-restricted senescent rats (TR) (24 months old) were investigated. Norepinephrine release in coronary effluent was determined by high performance liquid cromatography. IP significantly improved final recovery of percent developed pressure in hearts from A (p<0.01) but not in those from SL (p=NS) vs unconditioned controls. Developed pressure recovery was partial in hearts from TL and SR (64.3 and 67.3%, respectively; p<0.05 vs controls) but it was total in those from TR (82.3%, p=NS vs A; p<0.05 vs hearts from TL and SR). Similarly, IP determined a similar increase of norepinephrine release in A (p<0.001) and in TR (p<0.001, p=NS vs adult). IP was abolished by depletion of myocardial norepinephrine stores by reserpine in all groups. Thus, IP reduces post-ischemic dysfunction in A but not in SL. Moreover, IP was preserved partially in TR and SR and totally in TR. Complete IP maybe due to full restoration of norepinephrine release in response to IP stimulus. [Copyright &y& Elsevier]

Aim: To compare the uniformity and image quality between contrast media injection protocols adjusted for patient body weight (BW) versus body surface area (BSA) during coronary computed tomography (CT) angiography (CCTA).Materials and Methods: Consecutive patients (n=489) with suspected coronary artery disease were randomised prospectively to one of two CCTA protocols. In the BW protocol (n=245), patients received individualised iodine delivery rates (≤50 kg: 1 g/s; 51-60 kg: 1.2 g/s; 61-70 kg: 1.4 g/s; 71-80 kg: 1.6 g/s; 81-90 kg: 1.8 g/s; 91-100 kg: 2 g/s; >100 kg: 2.2 g/s). In the BSA protocol (n=244), patients received 9,600 mg iodine/m2 of contrast medium over 12 seconds. Attenuation and image noise were measured. Signal-to-noise ratio and contrast-to-noise ratio were calculated. Image quality was scored. Attenuation was assessed for correlation with BW and BSA using linear regression.Results: There were no statistically significant differences in mean arterial attenuation (396.8±47.6 versus 395.8±42.2 HU, p=0.804; 95% confidence interval: -7 to 9), image noise (25.2±5.8 versus 25.5±5.4 HU; p=0.549), signal-to-noise ratio (16.7±4.4 versus 16.6±3.6; p=0.902), contrast-to-noise ratio (25.1±5.8 versus 25.8±7.4; p=0.258) or image quality scores (4.1±0.9 versus 4±0.9; p=0.770) between the BW and BSA protocols. There was no correlation between BW and aortic attenuation or between BSA and aortic attenuation (p=0.324 and 0.932, respectively).Conclusion: The average contrast media attenuation and image quality was comparable between BW-adjusted protocol and BSA-adjusted protocol. [ABSTRACT FROM AUTHOR]

• The papers provides an overview on core thermal hydraulic CFD support for liquid metal cooled reactors. • An overview is provided on the necessary activities in the frame of design and safety support. • Validation efforts are discussed and summarized. • Simulations to analyze effect and origin of deformations and vibrations are presented. • Simulations for postulated accident conditions are introduced. Knowledge of the heat transport in the core is important for design and safety assessment of all nuclear reactors including liquid metal cooled reactors. In the past, design and safety calculations with respect heat transport in the core for such liquid metal cooled reactors were largely one-dimensional and based on experimental data. Nowadays, with modern state-of-the-art computer power and tools, three-dimensional Computational Fluid Dynamics (CFD) simulations allow designers and safety specialists to obtain much more detailed information on the heat transport in liquid metal cooled fuel assemblies, obviously supported by necessary experimental campaigns. This may lead to new insights possibly decreasing the safety margins. To this respect, an overview will be provided on the necessary activities in the frame of design and safety support using CFD for liquid metal reactors accompanied and illustrated by examples from NRG in the Netherlands. These examples include validation efforts for fuel assemblies as they are designed on the drawing board for 'cold' conditions. However, in reality, even under normal operational condition, a fuel assembly may deform. Therefore, an assessment of the effect of deformations resulting from operational conditions is necessary and will be shown. Another aspect possibly occurring during operational conditions is vibration. State-of-the-art coupled CFD and finite element method fluid structure interaction techniques have been developed and applied to a wire wrapped fuel assembly, providing insights in the vibration behavior of such assemblies. However, design and safety analysts will not only have to cope with operational conditions, but also have to show the heat transport behavior under accident conditions. For this, an assessment of the effect of internal and inlet blockages will be presented. [ABSTRACT FROM AUTHOR]