A multi-physics integrated approach to breeding blanket modelling and design

Spagnuolo, Gandolfo Alessandro; Chiovaro, P.; Maio, P.A. Di; Favetti, R.

doi:10.1016/j.fusengdes.2019.03.131

Cited by 14 publications

(6 citation statements)

References 16 publications

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“…This is due to the multiscale nature of the problem that requires integrating the equations over the several years of the BB lifetime, while capturing the details related to the pulsed operation, needing timescales of the order of few minutes. To overcome this issue a different approach with reference to analogous works [21,22] has been considered and a dedicated numerical method has been developed, with the aim to provide accurate results in a reduced amount of time, as described in the following.…”

Section: Description and Validation Of The Implemented Numerical Methodsmentioning

confidence: 99%

Production and transport modelling of Po-210 in DEMO reactor

Chiovaro¹,

Quartararo²,

Basile³

et al. 2022

Nucl. Fusion

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One of the generic designs of the nuclear fusion DEMO reactor proposed by the EUROfusion consortium foresees the development of a tritium Breeding Blanket (BB) relying on the use of the liquid-metal PbLi eutectic alloy as both neutron multiplier and tritium breeder, namely the Water-Cooled Lithium Lead (WCLL) BB, whose strengths and weaknesses are well known. This paper focuses the attention on one of the possible disadvantages of such a technology: the production of the highly radiotoxic radionuclide 210Po, which could become a safety issue to be accounted for. The 210Po concentration within the PbLi circuit has been assessed by solving a modified version of Bateman’s equations to consider the alloy circulation, so a one-dimensional convective fluid-dynamic model has been set up. Nuclear quantities have been evaluated by Monte Carlo neutron transport analyses using MCNP code and adopting a fully heterogeneous model of DEMO equipped with the WCLL BB. Moreover, rough sensitivity analyses have been performed to assess the influence on the results of the uncertainties related to the 209Bi radiative-capture cross section and the initial concentration of this nuclide which is present in the PbLi as an impurity. Results obtained have been critically discussed and some safety issues have been addressed to evaluate the possible hazard in case of a leak of PbLi accident.

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Section: Description and Validation Of The Implemented Numerical Methodsmentioning

confidence: 99%

Production and transport modelling of Po-210 in DEMO reactor

Chiovaro¹,

Quartararo²,

Basile³

et al. 2022

Nucl. Fusion

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“…Of course, the UM used for neutronic calculations is coarser than the mesh usually adopted for thermo-mechanical analyses, but this procedure naturally allows an easy coupling between nuclear and mechanical calculations. As far as boundary conditions are concerned, reflecting surfaces have been used both in the poloidal and toroidal direction, respectively [8,9] to take into account the geometrical continuity in those directions. Regarding the neutron source modelling, in the DEMO reactor neutrons enter the blanket directly from the plasma or after scattering (albedo effect) [8,10].…”

Section: Embrittlement Of the Wcll Blanketmentioning

confidence: 99%

“…As far as boundary conditions are concerned, reflecting surfaces have been used both in the poloidal and toroidal direction, respectively [8,9] to take into account the geometrical continuity in those directions. Regarding the neutron source modelling, in the DEMO reactor neutrons enter the blanket directly from the plasma or after scattering (albedo effect) [8,10]. In order to simulate these DEMO irradiation conditions, a local neutron source for the aforementioned WCLL BB slice model has been defined as a planar surface that emits neutrons biased in energy and cosine.…”

Section: Embrittlement Of the Wcll Blanketmentioning

confidence: 99%

“…For applying the approach to EUROFER structures, RT NDT needs to be determined and, in case of irradiated EUROFER, ∆T 41 and its dependence on irradiation dose are also required. Having T AV (68 J) known for EUROFER [19], RT NDT is assumed to be equal to T AV (68 J) − 33 K according to equation (8), resulting in RT NDT = −115 • C. For irradiated EUROFER, ∆T 41 is assumed to be equal to the shift in DBTT.…”

Section: Approach For Non-ductile Fracture Assessmentmentioning

confidence: 99%

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Embrittlement of WCLL blanket and its fracture mechanical assessment

et al. 2023

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In the European fusion programme, the Water Cooled Lithium Lead (WCLL) Breeding Blanket (BB) uses EUROFER as structural material cooled with water at temperatures comprised between 295-328°C and a pressure of 155 bar. The WCLL BB will be significantly irradiated (> 2 dpa) while some parts will not receive significant heat loads, e.g. the sidewalls or the back-supporting structures. The irradiation together with an irradiation temperature of EUROFER below 350°C produces a shift of the ductile-to-brittle-transition temperature (DBTT) to levels above room temperature at neutron doses causing material damage as low as 2-3 dpa. Even though the DBTT does not reach the operating temperature level, brittle/non-ductile fracture is a concern during in-vessel maintenance when the BB temperature is below the DBTT. Two loading senarios were identified as severe in this respect: (i) re-pressurization of the WCLL BB cooling loop after in-vessel maintenance, and (ii) dead weight loads during lifting of the BB segment.The embrittlement of the WCLL BB was investigated by quantifying the local DBTT shift in its parts based on nowadays knowledge of the embrittlement behaviour of EUROFER under neutron irradiation. Therefore, a suitable, not overly conservative procedure was derived considering dpa damage and transmuted helium effects. The results demonstrate the ability to identify the 3D spread of the severely embrittled zones in the structure whose impact on the structural integrity was assessed considering the risk of brittle/non-ductile fracture. Thereby, the fracture mechanics approach established in nuclear codes was applied assuming its applicability to EUROFER. The embrittled zones in the First Wall (FW) and its sidewalls pass the criteria when assessing the relatively low stresses resulting from the coolant pressure. The assessment was then continued considering stresses appearing in the FW during maintenance, in particular when lifting the BB segment and transporting it out of the vacuum vessel. In this context, the maximum tolerable flaw sizes were determined in a parameter study considering designs of the FW with different cooling channel wall thicknesses.

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“…It was used in various Japanese blanket conceptual designs. Spagnuolo [16] developed an integrated blanket design code system MCNP/ANSYS for neutronics, thermal-hydraulics, and the mechanics design of the blanket. The code system was applied in the water-cooled lithium lead blanket (WCLL) and the helium-cooled pebble bed blanket (HCPB) for the European DEMO project.…”

Section: Introductionmentioning

confidence: 99%

A Two-Way Neutronics/Thermal-Hydraulics Coupling Analysis Method for Fusion Blankets and Its Application to CFETR

Dai

Cao

et al. 2020

Energies

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The China Fusion Engineering Test Reactor (CFETR) is a tokamak device to validate and demonstrate fusion engineering technology. In CFETR, the breeding blanket is a vital important component that is closely related to the performance and safety of the fusion reactor. Neutronics/thermal-hydraulics (N/TH) coupling effect is significant in the numerical analysis of the fission reactor. However, in the numerical analysis of the fusion reactor, the existing coupling code system mostly adopts the one-way coupling method. The ignorance of the two-way N/TH coupling effect would lead to inaccurate results. In this paper, the MCNP/FLUENT code system is developed based on the 3D-1D-2D hybrid coupling method. The one-way and two-way N/TH coupling calculations for two typical blanket concepts, the helium-cooled solid breeder (HCSB) blanket and the water-cooled ceramic breeder (WCCB) blanket, are carried out to study the two-way N/TH coupling effect in CFETR. The numerical results show that, compared with the results from the one-way N/TH coupling calculation, the tritium breeding ration (TBR) calculated with the two-way N/TH calculation decreases by −0.11% and increases by 4.45% for the HCSB and WCCB blankets, respectively. The maximum temperature increases by 1 °C and 29 °C for the HCSB and WCCB blankets, respectively.

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A multi-physics integrated approach to breeding blanket modelling and design

Cited by 14 publications

References 16 publications

Production and transport modelling of Po-210 in DEMO reactor

Production and transport modelling of Po-210 in DEMO reactor

Embrittlement of WCLL blanket and its fracture mechanical assessment

A Two-Way Neutronics/Thermal-Hydraulics Coupling Analysis Method for Fusion Blankets and Its Application to CFETR

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