A CFD analysis of flow blockage phenomena in ALFRED LFR demo fuel assembly

Piazza, Ivan Di; Magugliani, Fabrizio; Tarantino, M.; Alemberti, A.

doi:10.1016/j.nucengdes.2014.05.033

Cited by 52 publications

(6 citation statements)

References 10 publications

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“…Pre-test CFD analysis shows the same basic phenomena of previous studies on larger bundles (Di Piazza, 2014) and documented in literature (Schultheiss, 1987) (Kirsch, 1975). A strong local effect is evident behind the blockage area leading to an elongated vortex with a decrease of heat transfer between the coolant and the cladding.…”

Section: Discussionsupporting

confidence: 80%

“…The mass flow rate was kept constant at the different degree of blockage. This is justified by the fact that in the real ALFRED FA geometry, blockage degrees up to 30% would not affect significantly the flow rate (Di Piazza, 2014) and the interest is focused on the local phenomena. Figure 7 shows the clad temperature distribution in the active region for the unblocked case 0.…”

Section: Numerical Models and Methodsmentioning

confidence: 99%

“…It is also seen that subassembly blockage that leads to 7% flow reduction in fuel subassembly and 12% flow reduction in blanket subassembly can be detected effectively by the core-temperature monitoring system. Di Piazza et al (2014) carried out a CFD study on fluid flow and heat transfer in the Lead-cooled Fuel Pin Bundle of the ALFRED LFR DEMO. The authors developed a detailed thermo-fluid dynamic analysis at various levels of geometrical blockage.…”

Section: Introductionmentioning

confidence: 99%

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Pre-test CFD simulations of the NACIE-UP BFPS test section

Marinari

Piazza

Forgione

et al. 2017

Annals of Nuclear Energy

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The present paper is focused on the CFD pre-test analysis and design of the new experimental facility Blocked Fuel Pin bundle Simulator (BFPS) that will be installed into the NACIE-UP (NAtural CIrculation Experiment-UPgrade) facility located at the ENEA Brasimone Research Center (Italy). The BFPS test section will carry out suitable experiments to fully investigate different flow blockage regimes in a 19 fuel pin bundle providing experimental data in support of the development of the ALFRED (Advanced Lead-cooled Fast Reactor European Demonstrator) LFR DEMO. The geometrical domain of the fuel pin bundle simulator was designed to reproduce the geometrical features of ALFRED, e.g. the external wrapper in the active region and the spacer grids. Pre-tests calculations were carried out by applying accurate boundary conditions; the conjugate heat transfer in the clad is also considered. The blockages investigated are internal blockages of different extensions and in different locations: central sub-channel blockage, corner sub-channel blockage, edge sub-channel blockage, one sector blockage, and two-sector blockage. RANS simulations were carried out adopting the ANSYS CFX commercial code with the laminar sublayer resolved by the mesh resolution. The loci of the peak temperatures and their width as predicted by the CFD simulations are used for determining the location of the pin bundle instrumentation. The CFD pre-test analysis allowed also investigating the temperature distribution in the clad to operate the test section safely

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Section: Discussionsupporting

confidence: 80%

Section: Numerical Models and Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Pre-test CFD simulations of the NACIE-UP BFPS test section

Marinari

Piazza

Forgione

et al. 2017

Annals of Nuclear Energy

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“…Up to now, researches on the key technologies of LFRs were firstly focused on material compatibility aspects, most notably on the degradation effects of the candidate's structure/clad materials due to liquid metal corrosion (LMC) and liquid metal embrittlement (LME) (OECD/ NEA, 2015; Gong et al, 2016;Huang et al, 2020a). Studies on thermal-hydraulic aspects have also been widely reported in the literature, for instance, on the heat transfer behavior in a wirewrapped fuel assembly (Cheng and Tak, 2006;Pacio et al, 2016;Pacio et al, 2017;Chai et al, 2019) and on the heat transfer deterioration due to flow blockage accident (Di Piazza et al, 2014;Chai et al, 2019). Furthermore, intensive investigations on liquid metal-water interaction during the steam generator tube rupture (SGTR) accident have also been conducted (Wang et al, 2008;Huang et al, 2020b;Yu et al, 2021).…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation on the Cleaning Effect and Influence Rule of Hydrogen Peroxide–Acetic Acid on Lead–Bismuth Eutectic Alloy

et al. 2021

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During the refueling process of lead–bismuth eutectic (LBE)–cooled fast reactors, lead–bismuth alloy can easily adhere to the surface of the fuel rod clads when spent fuel assemblies are unloaded from the reactor core. For some designs, the lead–bismuth alloy attached on the spent fuel rods will be cleaned via physical or/and chemical methods prior to their transportation, storage, and reprocessing. In this article, the cleaning effect of a washing lotion composed of hydrogen peroxide (H2O2) aqueous solution and concentrated acetic acid (CH3COOH) as the main components on LBE was experimentally investigated. By adjusting the composition ratio of the washing lotion and the reaction temperature, the law of their influence on the cleaning effect of LBE was determined. The optimal washing lotion composed of 30 Vol% hydrogen peroxide aqueous solution as oxidant, 40 Vol% concentrated acetic acid as acid, and 30 Vol% ultrapure water as the solvent was proposed based on experimental investigations. The optimal working temperature range was also obtained. The reaction intermediate product was characterized with the XRD analysis in order to understand the reaction mechanism. The composition of the released gas (even in a slight amount) was also analyzed with gas chromatography. The hydrogen concentration in the released gas was found to be lower than the detection limit of gas chromatography (10 ppm). Since the explosion limits of hydrogen at atmospheric pressure are between 3.95 and 75.73 Vol%, the risk of possible hydrogen explosion is concluded to be extremely low. Therefore, no special treatment of the released gas is required even in a large-scale industrial platform. Furthermore, corrosion effect of the washing lotion on austenitic stainless steel components was tested as well and found to be negligibly small. The relative mass loss of the thin-walled stainless steel samples immersed in the washing lotion was found to be less than 0.5% after an experimental duration of 144 h, which facilitates sufficient cleaning time in future industrial applications.

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“…In the simulations, both the natural convection under an instantaneous blockage and the forced convection with sub-channels partially blocked were modeled. Piazza et al (Piazza et al, 2014) modeled a partial blockage in a lead-cooled bundle under different blockage ratios with URANS, and the results show that a higher cladding temperature is induced by a larger area of blockage under the same boundary conditions. Chai et al (Chai et al, 2019) investigated the internal blockages in a subassembly with wire spacers numerically under the conditions with different positions and longitudes.…”

Section: Introductionmentioning

confidence: 99%

Numerical Study on the Thermal Hydraulic Characteristics in a Wire-Wrapped Assembly of LFRs

Fang

Guo

et al. 2020

Front. Energy Res.

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The concept of wire-wrapped assembly has been widely adopted in liquid metal-cooled reactors to enhance the capability of flow and heat transfer. The detailed 3D thermal hydraulic behaviors of liquid metal in the wire-wrapped assembly directly affect the safety of the reactor. In the present work, a numerical study on a 19-pin wire-wrapped assembly cooled by a lead-bismuth eutectic was carried out using the CFD method. The geometrical model is referred to in the test section in KIT’s 19-pin experiments, which is a scaled test assembly based on the MYRRHA reactor. The established CFD model was validated against experimental data and results showed that the SST k-ω model accompanied with the modified Prt was appropriate for the current problem. Then the numerical models were extensively used in the modeling of the blocked assembly flow with a cylindrical blockage. Also, the influences of blockage longitude, position, and porosity on the thermal hydraulic characteristics in the assembly were evaluated in detail. This work is meaningful for the deep understanding of safety features under the condition of assembly blockage operation in LFRs.

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A CFD analysis of flow blockage phenomena in ALFRED LFR demo fuel assembly

Cited by 52 publications

References 10 publications

Pre-test CFD simulations of the NACIE-UP BFPS test section

Pre-test CFD simulations of the NACIE-UP BFPS test section

Experimental Investigation on the Cleaning Effect and Influence Rule of Hydrogen Peroxide–Acetic Acid on Lead–Bismuth Eutectic Alloy

Numerical Study on the Thermal Hydraulic Characteristics in a Wire-Wrapped Assembly of LFRs

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