γ-photons and high-energy electrons produced by neutron irradiation in nuclear materials

Reali, Luca; Gilbert, Mark R.; Boleininger, Max; Dudarev, S. L.

doi:10.1016/j.jnucmat.2023.154584

Cited by 2 publications

(4 citation statements)

References 38 publications

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“…Neutron irradiation is a source of volumetric heating mediated by the colossal generation of γ-photons in the medium to heavy elements like W and Cu. Considering the DEMO neutron flux at the divertor region, we estimated the volumetric heating power of about 3 Watts per gram, on the basis of the analysis carried out in [8].…”

Section: Radiation Swelling Of An Iter Divertor Monoblockmentioning

confidence: 99%

“…We performed two transient heating simulations, one considering the scenario not involving irradiation and one introducing the three radiation-induced effects: swelling, reduced thermal conductivity, and the gamma heating. Similarly to the approach taken by Fursdon and You [2], we included the effect of irradiation on thermal conductivity and added radiation swelling to the setup of the simulation; we additionally also included the constant volumetric thermal power due to the neutron-induced gamma emission [8,9]. The results corresponding to the final time step are shown in figure 6.…”

Section: Radiation Swelling Of An Iter Divertor Monoblockmentioning

confidence: 99%

“…Neutrons alter the chemical composition of materials through transmutations, as has been extensively documented for tungsten [6,7]. Nonelastic neutron-nuclei reactions give rise to the intense generation of γ-photons in mediumto-heavy elements [8,9], which contribute to components' internal volumetric heating in addition to the direct heating by the plasma.…”

Section: Introductionmentioning

confidence: 99%

“…An extensively studied component of fusion reactors such as ITER or DEMO is a 'monoblock' tile consisting of a CuCrZr inner pipe, cooling the plasma-facing W armour, with a Cu interlayer joining the cooling pipe with the armour. Although several finite element method (FEM) studies of a monoblock were performed, involving coupled thermomechanical analysis [28][29][30][31][32], less attention was devoted to the investigation of effects of irradiation [2], even though the divertor is expected to be exposed to neutron fluxes that are among the highest anywhere in the DEMO reactor structure [8]. The central issue with the structural analysis of a monoblock is the lack of detailed materials data.…”

Section: Introductionmentioning

confidence: 99%

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Finite element models for radiation effects in nuclear fusion applications

Reali,

Dudarev

2024

Nucl. Fusion

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Deuterium-tritium fusion reactions produce energy in the form of 14.1 MeV neutrons, and hence fusion reactor components will be exposed to high energy neutron irradiation while also being subjected to thermal, mechanical and magnetic loads. Exposure to neutron irradiation has numerous consequences, including swelling and dimensional changes, comparable in magnitude to the peak transient thermal deformations occurring in plasma-facing components. Irradiation also dynamically alters the various thermo-mechanical properties, relating temperature, stress and swelling in a strongly non-linear way. Experimental data on the effect of neutron exposure spanning the design parameter space are very sparse and this highlights the relevance of computer simulations. In this study we explore the equivalence between the body force/surface traction approach and the eigenstrain formalism for treating anisotropic irradiation-induced swelling. We find that both commercial and massively parallelised open source software for finite element method (FEM) simulations are suitable for assessing the effect of neutron exposure on the mechanically loaded reactor components. We demonstrate how two primary effects of irradiation, radiation swelling and the degradation of thermal conductivity, affect the distributions of stress and temperature in the divertor of the ITER tokamak. Significant uncertainties characterising the magnitude of swelling and models for treating it suggest that on the basis of the presently available data, only an order of magnitude estimate can be given to the stress developing in reactor components most exposed to irradiation during service.

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Section: Radiation Swelling Of An Iter Divertor Monoblockmentioning

confidence: 99%