Economic analysis in risk management

Froio, Antonio; Bertinetti, Andrea; Savoldi, Laura; Zanino, Roberto; Cismondi, F.; Ciattaglia, S.

doi:10.1201/9781315210469-9

Cited by 3 publications

(5 citation statements)

References 7 publications

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“…when a 0D model would predict the opening of the BD). The intervention of bleed valves is not considered here, since it was already shown to have a negligible effect in the case of a large break [6], [13].…”

Section: Scenario and Geometry Descriptionmentioning

confidence: 99%

“…The imposed supersonic static pressure of 80 bar leads to an initial pressure ratio equal to 800 (see section III.A.2 below). The assumption of constant inlet pressure is reasonable, as the time span of interest for this simulation is limited to few tens of milliseconds, whereas the timescale for the depressurization of the Primary Heat Transfer System is of some seconds [6], [8], [13].…”

Section: Iiia1 Boundary Conditionsmentioning

confidence: 99%

“…where ρ is the fluid density, v is the average speed, L is a characteristic length (i.e. the distance between the inlet and the wall in front of it) and μ is the fluid dynamic viscosity, is >10 6 inside the jet region throughout the transient, so the flow regime is fully turbulent and, based on [20], the k- SST (Menter) [21] turbulence model has been chosen for the analysis.…”

Section: Iiib1 Modelmentioning

confidence: 99%

“…The results of the 3D model are then compared with those obtained with a 0D model developed with the GETTHEM code, which was already applied to the analysis of this kind of transients [6], [8]. The GETTHEM model adopted in this work is a modified version of that adopted in [8], fixing the mass flow rate at the inlet of the VV to the value computed by the CFD model, in order to guarantee that the total He mass in the system at the end of the transient is the same in both models; a sketch of the model is reported in Figure 9.…”

Section: D Cfd Vs 0d System-level Modelmentioning

confidence: 99%

“…The maximum and minimum target cell size, δM and δm, respectively, are defined according to Eqs. (5) and (6), respectively. Note that δM is the minimum between 0.5 m and three times the current size of the cell, i.e.…”

Section: Mesh Refinement Algorithmmentioning

confidence: 99%

See 4 more Smart Citations

3D transient CFD simulation of an in-vessel Loss-Of-Coolant Accident in the EU DEMO fusion reactor

Zappatore

Froio

Spagnuolo³

et al. 2020

Nucl. Fusion

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Accidental transients in fusion reactors, such as the in-vessel Loss-of-Coolant Accident (LOCA) considered here, are generally analyzed using system-level codes. However, because of their lumped nature, such tools cannot predict local pressure and temperature values, which are instead of interest to assess the integrity of the Vacuum Vessel (VV) structures. It is then fundamental to prove that the system-level tools' predictions are at least conservative. In this work, we analyze the helium flow inside the VV following a LOCA in the helium-cooled blanket of the EU DEMO, using a 3D transient CFD model implemented in the commercial STAR-CCM+ code. In view of the large pressure ratio, a hypersonic flow regime (Ma > 5) develops, with the formation of shock fronts requiring a high time and space resolution. The model is applied to compute the evolution of the pressure distribution inside the VV and then to compare it with the information provided by the system-level GETTHEM model. The predictions by the two models of the intervention time of the VV pressure suppression system are compared, showing that the 0D model is conservative.

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Section: Scenario and Geometry Descriptionmentioning

confidence: 99%

Section: Iiia1 Boundary Conditionsmentioning

confidence: 99%

Section: Iiib1 Modelmentioning

confidence: 99%

Section: D Cfd Vs 0d System-level Modelmentioning

confidence: 99%

Section: Mesh Refinement Algorithmmentioning

confidence: 99%

See 3 more Smart Citations

3D transient CFD simulation of an in-vessel Loss-Of-Coolant Accident in the EU DEMO fusion reactor

Zappatore

Froio

Spagnuolo³

et al. 2020

Nucl. Fusion

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Thermal-Hydraulic Analysis of the EU DEMO Helium-Cooled Pebble Bed Breeding Blanket Using the GETTHEM Code

Froio

Cismondi²,

Savoldi

et al. 2018

IEEE Trans. Plasma Sci.

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The GEneral Tokamak THErmal-hydraulic Model -GETTHEM has been updated to the most recent version of the EU DEMO Helium-Cooled Pebble Bed (HCPB) Breeding Blanket (BB) design. The GETTHEM results are first benchmarked in a controlled case against the results of 3D Computational Fluid-Dynamics computations, showing an acceptable accuracy despite the inherent simplifications in the GETTHEM model. GETTHEM is then applied to the evaluation of the poloidal hot-spot temperature distribution in an entire BB segment, showing that the maximum temperature in the EUROFER structures overcomes the design limit of 550 °C by more than 50 °C in some Blanket Modules. A possible mitigation strategy is then proposed and analyzed, based on the idea of cooling the First Wall in parallel with the breeding zone, showing that this solution would allow having the EUROFER in its working temperature range in the entire segment, although at the expense of a larger pressure drop.

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Hybrid 1D + 2D Modelling for the Assessment of the Heat Transfer in the EU DEMO Water-Cooled Lithium-Lead Manifolds

et al. 2020

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The European demonstration fusion power reactor (EU DEMO) tokamak will be the first European fusion device to produce electricity and to include a breeding blanket (BB). In the framework of the design of the EU DEMO BB, the analysis of the heat transfer between the inlet and outlet manifold of the coolant is needed, to assess the actual cooling capability of the water entering the cooling channels, as well as the actual coolant outlet temperature from the machine. The complex, fully three-dimensional conjugate heat transfer problem is reduced here with a novel approach to a simpler one, decoupling the longitudinal and transverse scales for the heat transport by developing correlations for a conductive heat-transfer problem. While in the longitudinal direction a standard 1D model for the heat transport by fluid advection is adopted, a set of 2D finite elements analyses are run in the transverse direction, in order to lump the 2D heat conduction effects in suitable correlations. Such correlations are implemented in a 1D finite volume model with the 1D GEneral Tokamak THErmal-hydraulic Model (GETTHEM) code (Politecnico di Torino, Torino, Italy); the proposed approach thus reduces the 3D problem to a 1D one, allowing a parametric evaluation of the heat transfer in the entire blanket with a reduced computational cost. The deviation from nominal inlet and outlet temperature values, for the case of the Water-Cooled Lithium-Lead BB concept, is found to be always below 1.4 K and, in some cases, even to be beneficial. Consequently, the heat transfer among the manifolds at different temperatures can be safely (and conservatively) neglected.

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Economic analysis in risk management

Cited by 3 publications

References 7 publications

3D transient CFD simulation of an in-vessel Loss-Of-Coolant Accident in the EU DEMO fusion reactor

3D transient CFD simulation of an in-vessel Loss-Of-Coolant Accident in the EU DEMO fusion reactor

Thermal-Hydraulic Analysis of the EU DEMO Helium-Cooled Pebble Bed Breeding Blanket Using the GETTHEM Code

Hybrid 1D + 2D Modelling for the Assessment of the Heat Transfer in the EU DEMO Water-Cooled Lithium-Lead Manifolds

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