Set-up of a pre-test mock-up experiment in preparation for the HCPB Breeder Unit mock-up experimental campaign

Hernández, Francisco A.; Kolb, M.H.H.; Ilić, Milica; Kunze, André; Németh, József; Weth, A. von der

doi:10.1016/j.fusengdes.2013.02.107

Cited by 6 publications

(6 citation statements)

References 13 publications

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“…The second factor for the occurrence of "hot spots" can be addressed if the neutronics calculation can consider the heterogeneity within the granular materials, and provide a better way to take into account the transition between the average heating profile and the actual heating power for individual pebbles. The maximum temperature found inside the bed is around 650 • C, which is lower compared with the finite element (FE) calculations, 16 around 720 • C. The main reasons are: (1) the FE analyses have not considered the effective thermal conductivity with strain dependency which overestimated the maximum temperature;…”

Section: Resultsmentioning

confidence: 85%

“…Based on the EU breeder unit design 16 in Fig. 1(a), the neutron heating profile for the ceramic breeder materials has been calculated in 17 for Li 4 SiO 4 .…”

Section: Iia Thermal Discrete Element Methodsmentioning

confidence: 99%

“…Schematics of the approach: (a) EU design for ITER-TBM unit adopted from;16 (b) calculated power density of neutron irradiation during operation from; 17 (c) Thermal-DEM model for two pebbles, with mechanical interaction F i j , volumetric heating Ψ i , and heat fluxes φ cont i j and φ gap i j for solid-tosolid and gap conduction, respectively.…”

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confidence: 99%

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Thermal Discrete Element Analysis of EU Solid Breeder Blanket Subjected to Neutron Irradiation

Gan

Hernández

Hanaor

et al. 2014

Fusion Science and Technology

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Due to neutron irradiation, solid breeder blankets are subjected to complex thermo-mechanical conditions. Within one breeder unit, the ceramic breeder bed is composed of sphericalshaped lithium orthosilicate pebbles, and as a type of granular material, it exhibits strong coupling between temperature and stress fields. In this paper, we study these thermo-mechanical problems by developing a thermal discrete element method (Thermal-DEM). This proposed simulation tool models each individual ceramic pebble as one element and considers grainscale thermo-mechanical interactions between elements. A small section of solid breeder pebble bed in HCPB is modelled using thousands of individual pebbles and subjected to volumetric heating profiles calculated from neutronics under ITER-relevant conditions. We consider heat transfer at the grain-scale between pebbles through both solid-to-solid contacts and the interstitial gas phase, and we calculate stresses arising from thermal expansion of pebbles. The overall effective conductivity of the bed depends on the resulting compressive stress state during the neutronic heating. The thermal-DEM method proposed in this study provides the access to the grainscale information, which is beneficial for HCPB design and breeder material optimization, and a better understanding of overall thermo-mechanical responses of the breeder units under fusion-relevant conditions. 1

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Section: Resultsmentioning

confidence: 85%

“…Based on the EU breeder unit design 16 in Fig. 1(a), the neutron heating profile for the ceramic breeder materials has been calculated in 17 for Li 4 SiO 4 .…”

Section: Iia Thermal Discrete Element Methodsmentioning

confidence: 99%

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Thermal Discrete Element Analysis of EU Solid Breeder Blanket Subjected to Neutron Irradiation

Gan

Hernández

Hanaor

et al. 2014

Fusion Science and Technology

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“…Pebble bed widths in ζ are 20 mm, a size comparable to breeding volumes of many ITER TBM designs [3][4][5]. Bed depths (in the z-direction, in/out of the page in Figures 1a and 1b) are 5 mm, with periodic boundary conditions.…”

Section: Simulation Domain Boundary Conditions Andmentioning

confidence: 87%

“…Thus χ-configurations, shown in Figure 1a, have χ = y and ζ = x while ζ-configurations, Figure 1b, have χ = x and ζ = y. The ζ-configuration in this study is meant to represent the orientation of European Union's TBM [3], while the χ configuration is an orientation adopted by many other current TBM designs in ITER [4,5].…”

Section: Simulation Domain Boundary Conditions Andmentioning

confidence: 99%

Numerical study on influences of bed resettling, breeding zone orientation, and purge gas on temperatures in solid breeders

Lew¹,

Ying²,

Abdou³

2016

Fusion Engineering and Design

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We apply coupled computational fluid dynamics and discrete element method (CFD-DEM) modeling tools with new numerical implementations of pebble fragmentation to study the combined effects of granular crushing and ensemble restructuring, granular fragment size, and initial packing for different breeder volume configurations. In typical solid breeder modules, heat removal from beds relies on maintaining pebblepebble and pebble-wall contact integrity. However, contact is disrupted when an ensemble responds to individually-crushed pebbles. Furthermore, restructuring of metastable packings after crushing events are, in part, dependent on gravity forces acting upon the pebbles. We investigate two representative pebble bed configurations under constant volumetric heat sources; modeling heat removed from beds via inter-particle conduction, purge gas convection, and contact between pebble beds and containers. In one configuration, heat is removed from at walls oriented parallel to the gravity vector (no gap formation possible); in the second, heat is removed at walls perpendicular to gravity, allowing for the possibility of gap formation between bed and wall. Judging beds on increase in maximum temperatures as a function of crushed pebble amount, we find that both pebble bed configurations to have advantageous features that manifest at different stages of pebble crushing. However, all configurations benefit from achieving high initial packing fractions.

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Ceramic Breeder Materials

Laan

Reimann

Fedorov

2016

Comprehensive Nuclear Materials

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Set-up of a pre-test mock-up experiment in preparation for the HCPB Breeder Unit mock-up experimental campaign

Cited by 6 publications

References 13 publications

Thermal Discrete Element Analysis of EU Solid Breeder Blanket Subjected to Neutron Irradiation

Thermal Discrete Element Analysis of EU Solid Breeder Blanket Subjected to Neutron Irradiation

Numerical study on influences of bed resettling, breeding zone orientation, and purge gas on temperatures in solid breeders

Ceramic Breeder Materials

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