Modeling long-term distribution of fast and thermal neutron fluence in degraded concrete biological shielding walls

Jing, Yuxiang; Xi, Yunping

doi:10.1016/j.conbuildmat.2021.123379

Cited by 7 publications

(4 citation statements)

References 20 publications

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“…The time of analysis is 1 year; the time step used in the analysis is 1×10 -6 s. The concrete properties used in the analyses are listed in Table 1. Table 1: Parameters used in the numerical example (thermal, and neutron diffusion parameters are taken from reference [2]).…”

Section: Numerical Resultsmentioning

confidence: 99%

“…This is true as long as one accepts that heat due to scattering is negligible, if compared to heat generated by the capture of thermal neutrons. The neutron radiation induced heating rate by absorption can be estimated as [2] 𝑄𝑄(𝑿𝑿, 𝑡𝑡) = 1.6 × 10 −13 Σ 𝑐𝑐 ℰ 𝑏𝑏 𝜙𝜙 2 (𝑿𝑿, 𝑡𝑡) (10) where Σ 𝑐𝑐 is the macroscopic neutron capture cross section, and ℰ 𝑏𝑏 is the binding energy for the capture process.…”

Section: Mathematical Modelmentioning

confidence: 99%

“…Since neutron radiation can deteriorate the mechanical properties of concrete materials, it is critical to obtain accurate neutron radiation levels in concrete structures during their service life. Often, this problem is addressed via analytical simplified 1D studies [2].…”

Section: Introductionmentioning

confidence: 99%

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A coupled thermo-mechanical and neutron diffusion numerical model for irradiated concrete

Zhang

2023

Theoretical and Applied Mechanics - AIMETA 2022

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Neutron irradiation plays an important role in nuclear-induced degradation for concrete shielding materials, specifically in determining the radiation induced volume expansion (RIVE) phenomenon driving its failure. When analyzing at the structural level the effects of nuclear radiation on concrete, a non-uniformed distribution of neutron radiation must be considered. This can be done via particle transport calculations preventive to the thermo-mechanic study, or by solving numerically the coupled set of governing equations of the problem. In this work the second approach is pursued in the theoretical framework of the Finite Element Method (FEM). The proposed formulation not only considers an accurate neutron transport model based on the two-group theory, but also it includes the effects induced by thermal neutrons to the temperature field. The formulation lends itself to include RIVE and the other relevant radiation induced effects on the mechanical field. The governing equations are presented and discussed, and some results obtained by using the general 3D numerical formulation proposed herein are compared to results from literature obtained via analytical methods addressing simplified 1D problems.

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Section: Numerical Resultsmentioning

confidence: 99%

Section: Mathematical Modelmentioning

confidence: 99%

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A coupled thermo-mechanical and neutron diffusion numerical model for irradiated concrete

Zhang

2023

Theoretical and Applied Mechanics - AIMETA 2022

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“…Within the shielding walls of nuclear facilities the neutron flux is not uniformly distributed. The evaluation of damage triggering and propagation in irradiated concrete members demands a precise prediction of the neutron flux distribution on concrete structures [5]. Further, in the shielding process radiation energy is partially transformed into heat, which leads to temperature rise and additional damage [6].…”

Section: Introductionmentioning

confidence: 99%

On the effects of aggregate sievingin the shielding and thermo-mechanical performance of concrete

Zhang,

Pomaro,

Mazzucco

et al.

Proceedings of the Seventeenth International Conference On Civil, Structural and Environmental Engineering Computing

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In this paper, the influence of aggregate sieving and distribution on the shielding performance of concrete against nuclear radiation is investigated numerically. A thermomechanical and neutron diffusion coupled numerical formulation is proposed to address the specific problem related to irradiated concrete. This model solves the multiphysics problem by combining a two-group neutron diffusion theory, with the thermal conduction equation adapted to the radiation condition, and the mechanical equilibrium problem. Concrete is modeled at the mesoscale as a two-phase material, comprising mortar matrix and aggregates. Three grading curves of Fuller type are simulated, different for the nominal diameter size intervals of the polyhedral aggregates, which are randomly distributed within cubic samples of concrete composite material. A boron-rich material, colemanite, is utilized as aggregate in the numerical simulations. The results show that the fast neutron flux is not much influenced by the variation of the grading curves. On the other hand, a slight variation of the coarse aggregate volume fraction is found to affect to some extent the thermal flux. As regards temperature and stress distribution, it is noted the barrier effects that the inclusions bring to the state variable diffusion process.

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Numerical investigations on the viscoelastic-damage behaviors of RIVE-induced concrete

Chen

Gao²,

Jin³

et al. 2023

International Journal of Mechanical Sciences

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Modeling long-term distribution of fast and thermal neutron fluence in degraded concrete biological shielding walls

Cited by 7 publications

References 20 publications

A coupled thermo-mechanical and neutron diffusion numerical model for irradiated concrete

A coupled thermo-mechanical and neutron diffusion numerical model for irradiated concrete

On the effects of aggregate sievingin the shielding and thermo-mechanical performance of concrete

Numerical investigations on the viscoelastic-damage behaviors of RIVE-induced concrete

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