المؤلفون: Qingming He, Zhanpeng Huang, Liangzhi Cao, Hongchun Wu

المصدر: Nuclear Engineering and Technology, Vol 56, Iss 7, Pp 2748-2755 (2024)

مصطلحات موضوعية: Monte Carlo, Variance reduction, Next-event estimator, DXTRAN, CADIS, Nuclear engineering. Atomic power, TK9001-9401

الوصف: This paper presents two new methods for variance reduction for shielding calculation in Monte Carlo radiation transport. One method is CADIS-NEE, which combines Consistent Adjoint Driven Importance Sampling (CADIS) and next-event estimator (NEE) methods to increase the calculation efficiency of tallies at points. The other is CADIS-deterministic transport (DXTRAN), which combines CADIS and DXTRAN to obtain higher performance than using CADIS and DXTRAN separately. The combination processes are derived and implemented in the hybrid Monte-Carlo-Deterministic particle-transport code NECP-MCX. Various problems are tested to demonstrate the effectiveness of the two methods. According to the results, the two combination methods have higher efficiency than using CADIS, NEE or DXTRAN separately. In a long-distance photon-transport problem, CADIS-NEE converges faster than NEE and the figure of merit (FOM) of CADIS-NEE is 75.6 times of NEE. In a labyrinthine problem, CADIS-DXTRAN's FOM surpasses that of DXTRAN and CADIS by a factor of 45.3 and 17.7, respectively. Therefore, it is advisable to employ these two novel methods selectively in appropriate scenarios to reduce variance.

وصف الملف: electronic resource

Relation: http://www.sciencedirect.com/science/article/pii/S1738573324000962; https://doaj.org/toc/1738-5733

URL الوصول: https://doaj.org/article/b8c16ace43fe49ac998dc4ad043f5224

المؤلفون: Xingjie Peng, Shichang Liu, Qingming He, Jingang Liang, Jiankai Yu

المصدر: Frontiers in Energy Research, Vol 12 (2024)

مصطلحات موضوعية: multi-physics, multi-scale, modeling and simulation, nuclear reactor, radiation damage, General Works

وصف الملف: electronic resource

Relation: https://www.frontiersin.org/articles/10.3389/fenrg.2024.1361541/full; https://doaj.org/toc/2296-598X

URL الوصول: https://doaj.org/article/fd7d7b1382d14e0d98b757cbbe2255d5

المؤلفون: Shuai Qin, Yunzhao Li, Qingming He, Liangzhi Cao, Yongping Wang, Yuxuan Wu, Hongchun Wu

المصدر: Nuclear Engineering and Technology, Vol 55, Iss 9, Pp 3450-3463 (2023)

مصطلحات موضوعية: Pebble-bed, Monte Carlo, NECP-MCX, Homogenization, Nuclear engineering. Atomic power, TK9001-9401

الوصف: In the two-step analysis of Pebble-Bed type High-Temperature Gas-Cooled Reactor (PB-HTGR), the lattice physics calculation for the generation of homogenized cross-sections is based on the fuel pebble. However, the randomly-dispersed fuel particles in the fuel pebble introduce double heterogeneity and randomness. Compared to the deterministic method, the Monte Carlo method which is flexible in geometry modeling provides a high-fidelity treatment. Therefore, the Monte Carlo code NECP-MCX is extended in this study to perform the lattice physics calculation of the PB-HTGR. Firstly, the capability for the simulation of randomly-dispersed media, using the explicit modeling approach, is developed in NECP-MCX. Secondly, the capability for the generation of the homogenized cross-section is also developed in NECP-MCX. Finally, simplified PB-HTGR problems are calculated by a two-step neutronics analysis tool based on Monte Carlo homogenization. For the pebble beds mixed by fuel pebble and graphite pebble, the bias is less than 100 pcm when compared to the high-fidelity model, and the bias is increased to 269 pcm for pebble bed mixed by depleted fuel pebble. Numerical results show that the Monte Carlo lattice physics calculation for the two-step analysis of PB-HTGR is feasible.

وصف الملف: electronic resource

Relation: http://www.sciencedirect.com/science/article/pii/S1738573323002553; https://doaj.org/toc/1738-5733

URL الوصول: https://doaj.org/article/ee5fb68f97b84bd1b5894b9cf9095ffe

المؤلفون: Jiaqi Hu, Zhaopeng Qiao, Lunhe Fan, Yongqiang Tang, Liangzhi Cao, Tiejun Zu, Qingming He, Zhifeng Li, Sheng Wang

المصدر: Nuclear Engineering and Technology, Vol 55, Iss 4, Pp 1280-1286 (2023)

مصطلحات موضوعية: Beam shaping assembly, Thermal neutron scattering data of MgF2, Phonon density of states, Monte-Carlo method, Nuclear engineering. Atomic power, TK9001-9401

الوصف: MgF2 as a moderator material has been extensively used in the beam shaping assembly (BSA) that plays an important role in the boron neutron capture therapy (BNCT). Regarded as important for applications, the thermal neutron scattering data of MgF2 were calculated, based on the phonon expansion model. The structural properties of MgF2 were researched by the VASP code based on the ab-initio methods. The PHONOPY code was employed to calculate the phonon density of states. Furthermore, the NJOY code was used to calculate the thermal neutron scattering data of MgF2. The calculated inelastic cross sections plus absorption cross sections are in agreement with the available experimental data. The neutron transport in the BSA has been simulated by using a hybrid Monte-Carlo-Deterministic code NECP-MCX. The results indicated that compared with the calculation of the free gas model, the thermal neutron flux and epithermal neutron flux at the BSA exit port calculated by using the thermal neutron scattering data of MgF2 were reduced by 27.7% and 8.2%, respectively.

وصف الملف: electronic resource

Relation: http://www.sciencedirect.com/science/article/pii/S1738573322005940; https://doaj.org/toc/1738-5733

URL الوصول: https://doaj.org/article/0239ab00217b4414b53cbb97a1b15d53

المؤلفون: Qing Liu, Qingming He, Ruoyun Li, Yanfei Feng, Xianjun Lyu, Junxiang Wang, Lin Li

المصدر: International Journal of Mining Science and Technology, Vol 32, Iss 6, Pp 1407-1418 (2022)

مصطلحات موضوعية: Alkali-activated slag, Colloidal nanosilica, Strength, Hydration kinetics, C-A-S-H gel, Mining engineering. Metallurgy, TN1-997

الوصف: To solve the energy consumption and CO2 emission during cement production, the new binders must be developed as an alternative to cement. CaO/CaSO4-activated slag binder is an eco-friendly and safe cementitious material; however, its low strength during initial stages limits its applications. In this study, colloidal nanosilica (CNS) was employed as an additive to improve the strength of CaO/CaSO4-activated slag binder, and the effects of CNS on the workability, hydration kinetics, hydration products (type, quantity, and polymerization degree), and binder microstructure were thoroughly investigated. A moderate CNS content, through its nucleation effect, significantly increased the hydration rate of the nucleation and crystal growth (NG), phase boundary interaction (I) and diffusion (D) processes, which generated large quantities of calcium aluminosilicate hydrate (C-A-S-H) gel in the initial hydration stage. Meanwhile, the addition of CNS improved the polymerization degree of C-A-S-H gel. This amorphous reactant well-filled the pore space between slag particles and yielded a compact microstructure, consequently enhancing the binder strength. Considering the reduction in fluidity and the increase in production cost, the CNS mass fraction was controlled as ∼3%, and the binder reached the satisfactory strengths of 3.87, 24.47, 31.43, and 41.78 MPa at 1, 3, 7, and 28 d, respectively.

وصف الملف: electronic resource

Relation: http://www.sciencedirect.com/science/article/pii/S2095268622000696; https://doaj.org/toc/2095-2686

URL الوصول: https://doaj.org/article/5d64a3c39f394e18b7bd83a61ce8b0d4

المؤلفون: Dingwei Zheng, Qingming He

المصدر: Mathematics, Vol 11, Iss 24, p 4898 (2023)

مصطلحات موضوعية: fuzzy metric, positive, stationary, Lipschitz condition, Mathematics, QA1-939

الوصف: In this note, we prove that for two compatible fuzzy metrics MH and MK on H and K, respectively, there exists a fuzzy metric M on H⋃K such that M|H=MH and M|K=MK under the conditions that t-norm ∗ is positive and fuzzy metrics MH,MK are strong, or t-norm ∗ is positive and t-norm ∗, fuzzy metrics MH,MK satisfy the Lipschitz conditions.

وصف الملف: electronic resource

Relation: https://www.mdpi.com/2227-7390/11/24/4898; https://doaj.org/toc/2227-7390

URL الوصول: https://doaj.org/article/67d6b29e22a14257a4f44a0a329b9627

المؤلفون: Shichang Liu, Jingang Liang, Jiankai Yu, Qingming He, Yang Liu

المصدر: Frontiers in Energy Research, Vol 11 (2023)

مصطلحات موضوعية: modeling and simulation, reactor analysis methodology, reactor physics, thermal-hydraulics, artificial intelligence, high performance computing, General Works

وصف الملف: electronic resource

Relation: https://www.frontiersin.org/articles/10.3389/fenrg.2023.1189328/full; https://doaj.org/toc/2296-598X

URL الوصول: https://doaj.org/article/1fbef4561c5d41fc9bbb45b42dbd4bbc

المؤلفون: Tiejun Zu, Yongqiang Tang, Zhanpeng Huang, Shuai Qin, Jie Li, Qingming He, Liangzhi Cao, Hongchun Wu

المصدر: Frontiers in Energy Research, Vol 9 (2021)

مصطلحات موضوعية: thermal scattering cross section, nuclear data processing, inelastic scattering, mixed elastic scattering, NECP-Atlas, General Works

الوصف: In the conventional method to generate thermal scattering cross section of moderator materials, only one of the coherent elastic scattering and incoherent elastic scattering is considered in neutronics calculations. For the inelastic scattering, fixed incident energy grid is used in the nuclear data processing codes. The multipoint linearization method is used to refine the incident energy grid for inelastic scattering. We select ZrHx (zirconium hydride) as an example to analyze the effects of the above described treatments on the reactivity of several critical benchmarks. The numerical results show that the incident energy grid has an obvious effect on the effective multiplication factor (keff) of the analyzed reactors; simultaneously considering the coherent and incoherent elastic scattering also affects keff by tens of pcm.

وصف الملف: electronic resource

Relation: https://www.frontiersin.org/articles/10.3389/fenrg.2021.779261/full; https://doaj.org/toc/2296-598X

URL الوصول: https://doaj.org/article/b05187629394468f92af1341a3c38a85

المؤلفون: Qingming He, Yijun Zhang, Zhouyu Liu, Liangzhi Cao, Hongchun Wu

المصدر: Nuclear Engineering and Technology, Vol 52, Iss 2, Pp 258-270 (2020)

مصطلحات موضوعية: Nuclear engineering. Atomic power, TK9001-9401

الوصف: A new task of using the Jacobian-Free-Newton-Krylov (JFNK) method for the PWR core transient simulations involving neutronics, thermal hydraulics and mechanics is conducted. For the transient scenario of PWR, normally the Picard iteration of the coupled coarse-mesh nodal equations and parallel channel TH equations is performed to get the transient solution. In order to solve the coupled equations faster and more stable, the Newton Krylov (NK) method based on the explicit matrix was studied. However, the NK method is hard to be extended to the cases with more physics phenomenon coupled, thus the JFNK based iteration scheme is developed for the nodal method and parallel-channel TH method. The local gap conductance is sensitive to the gap width and will influence the temperature distribution in the fuel rod significantly. To further consider the local gap conductance during the transient scenario, a 1D mechanics model is coupled into the JFNK scheme to account for the fuel thermal expansion effect. To improve the efficiency, the physics-based precondition and scaling technique are developed for the JFNK iteration. Numerical tests show good convergence behavior of the iterations and demonstrate the influence of the fuel thermal expansion effect during the rod ejection problems. Keywords: Multi-physics, Neutronics/TH/Mechanics, JFNK, Preconditioning, Transient

وصف الملف: electronic resource

Relation: http://www.sciencedirect.com/science/article/pii/S173857331930436X; https://doaj.org/toc/1738-5733

URL الوصول: https://doaj.org/article/713ee7e8e1704c538879c2385e0f2af8

المؤلفون: Tao Dai, Liangzhi Cao, Qingming He, Hongchun Wu, Wei Shen

المصدر: Energies, Vol 13, Iss 16, p 4070 (2020)

مصطلحات موضوعية: CFETR, fusion blanket, Neutronics/thermal-hydraulics Coupling, Technology

الوصف: 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.

وصف الملف: electronic resource

Relation: https://www.mdpi.com/1996-1073/13/16/4070; https://doaj.org/toc/1996-1073

URL الوصول: https://doaj.org/article/39d12560d46147dbac43b876fb833d6e