Design and R&amp;D progress of Korean HCCR TBM

Cho, Seungyon; Ahn, Min Cheol; Lee, Jun Young; Park, Yi-Hyun; Lee, Eo Hwak; Jin, Hyung Gon; Lee, Cheol Woo; Kim, Tae Kyu; Chun, Young-Bum; Kim, Suk Kwon; Yoon, Jae Sung; Yun, Young-Sun; Jung, Yang‐Il; Lee, Young-Min; Shin, Kyong‐Oh; Ku, Duck Young; Park, Soon Chang; Kim, Chang-Shuk; Min, Kyung-Mi; Jeong, Yong Hwan; Lee, Young Ouk; Jung, Ki-Jung

doi:10.1016/j.fusengdes.2014.01.032

Cited by 39 publications

(8 citation statements)

References 17 publications

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“…In molten carbonate fuel cells (MCFCs), LiAlO 2 is used as the electrolyte matrix . In fusion energy, LiAlO 2 is a candidate material for producing tritium in a tritium breeder blanket . LiAlO 2 has also been used to produce tritium inside a tritium‐producing‐burnable‐absorber‐rod (TPBAR) in conventional nuclear fission reactors .…”

Section: Introductionmentioning

confidence: 99%

Role of interfaces in damage process of irradiated lithium aluminate nanocrystals

Senor

Devanathan

2018

J Am Ceram Soc

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Molecular dynamics simulations were performed to understand the differences in the response of single crystal and nanocrystalline γ‐LiAlO2 to energy deposition by 10 keV Li recoils. The simulations are performed at 573 K and focus on the damage production in the absence of thermal annealing. The grain boundaries in the nanocrystals are found to be amorphous. Analyses of the fate of the beam ions show that the amorphous grain boundaries and differently oriented nanograins increase the number of backscattered ions and decrease the number of transmitted ions. Damaged regions protruding from the grain boundaries provide a direct evidence of the role of the grain boundaries as scattering centers in collision cascades. The simulations show that the defect density produced in the nanocrystals is about twice that in the single crystals. In both samples, Li defects account for 70% of the defects, demonstrating that LiO4 tetrahedra are much more susceptible to damage than AlO4 tetrahedra. Furthermore, Li defects occur preferentially near grain boundaries. Diffusion simulations confirm the limited thermal diffusion of defects at 573 K, effectively separating the damage production from thermal annealing in the irradiation simulations. Nevertheless, the mean square displacements of grain‐boundary defects are found to be larger than lattice defects and surface defects.

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Section: Introductionmentioning

confidence: 99%

Role of interfaces in damage process of irradiated lithium aluminate nanocrystals

Senor

Devanathan

2018

J Am Ceram Soc

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“…For example, under complicated construction conditions, TBMs' excavation process will be faced with high risk caused by an unanticipated presence of water leakage, rock spalling, geological faulting, weak regions, break outs of the tunnel wall and subsidence of work area. To improve TBMs' reliability and reduce unscheduled downtime, some research works have paid attention to TBMs' risk evaluation [4], design and R&D [5], and safety decision [6].…”

Section: Introductionmentioning

confidence: 99%

Real-time Forecast Models for TBM Load Parameters Based on Machine Learning Methods

Gao¹,

Song²,

Shi³

et al. 2021

Preprint

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Because of the fast advance rate and the improved personnel safety, tunnel boring machines (TBMs) have been widely used in a variety of tunnel construction projects. The dynamic modeling of TBM load parameters (including torque, advance rate and thrust) plays an essential part in the design, safe operation and fault prognostics of this complex engineering system. In this paper, based on in-situ TBM operational data, we use the machine-learning (ML) methods to build the real-time forecast models for TBM load parameters, which can instantaneously provide the future values of the TBM load parameters as long as the current data are collected. To decrease the model complexity and improve the generalization, we also apply the least absolute shrinkage and selection (Lasso) method to extract the essential features of the forecast task. The experimental results show that the forecast models based on deep-learning methods, e.g., recurrent neural network and its variants, outperform the ones based on the shallow-learning methods, e.g., support vector regression and random forest. Moreover, the Lasso-based feature extraction significantly improves the performance of the resultant models.

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“…The blanket is composed of the tritium breeding lithium ceramic pebbles and neutron multiplying beryllium pebbles. Similar concepts are being investigated in China, Korea, and India [5][6][7][8], while Japan is exploring a ceramic breeder cooled by pressurized water [9]. Other blanket designs utilize lead to lower chemical reactivity [10]; LiPb alone can serve as a breeder, coolant, neutron multiplier, and tritium carrier.…”

Section: Introductionmentioning

confidence: 99%

Neutronics and activation analysis of lithium-based ternary alloys in IFE blankets

Jolodosky

Kramer

Meier

et al. 2016

Fusion Engineering and Design

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h i g h l i g h t s • Monte Carlo calculations were performed on numerous lithium ternary alloys. • Elements with high neutron multiplication performed well with low absorbers. • Enriching lithium decreases minimum lithium concentration of alloys by 60% or more. • Alloys that performed well neutronically were selected for activation calculations. • Alloys activated, except LiBaBi, do not pose major environmental or safety concerns. a b s t r a c t An attractive feature of using liquid lithium as the breeder and coolant in fusion blankets is that it has very high tritium solubility and results in very low levels of tritium permeation throughout the facility infrastructure. However, lithium metal vigorously reacts with air and water and presents plant safety concerns. The Lawrence Livermore National Laboratory is carrying an effort to develop a lithium-based ternary alloy that maintains the beneficial properties of lithium (e.g. high tritium breeding and solubility) and at the same time reduces overall flammability concerns. This study evaluates the neutronics performance of lithium-based alloys in the blanket of an inertial fusion energy chamber in order to inform such development. 3-D Monte Carlo calculations were performed to evaluate two main neutronics performance parameters for the blanket: tritium breeding ratio (TBR), and the fusion energy multiplication factor (EMF). It was found that elements that exhibit low absorption cross sections and higher q-values such as Pb, Sn, and Sr, perform well with those that have high neutron multiplication such as Pb and Bi. These elements meet TBR constrains ranging from 1.02 to 1.1. However, most alloys do not reach EMFs greater than 1.15. Additionally, it was found that enriching lithium with 6 Li significantly increases the TBR and decreases the minimum lithium concentration by more than 60%. The amount of enrichment depends on how much total lithium is in the alloy to begin with. Alloys that performed well in the TBR and EMF calculations were considered for activation analysis. Activation simulations were executed with 50 years of irradiation and 300 years of cooling. It was discovered that bismuth is a poor choice due to achieving the highest decay heat, contact dose rates, and accident doses. In addition, it does not meet the waste disposal ratings (WDR). Some of the activation results for alloys with Sn, Zn, and Ga were in the higher end and should be considered secondary to elements such as Sr and Ba that had overall better results. The results of this study along with other considerations such as thermodynamics, and chemical reactivity will help down select a preferred lithium ternary alloy.

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Design and R&D progress of Korean HCCR TBM

Cited by 39 publications

References 17 publications

Role of interfaces in damage process of irradiated lithium aluminate nanocrystals

Role of interfaces in damage process of irradiated lithium aluminate nanocrystals

Real-time Forecast Models for TBM Load Parameters Based on Machine Learning Methods

Neutronics and activation analysis of lithium-based ternary alloys in IFE blankets

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