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Optimizing near-carbon-free nuclear energy systems:advances in reactor operation digital twin through hybrid machine learning algorithms for parameter identification and state estimation

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Nuclear Science and Techniques 2024年第8期35卷 177-203页

作者： Li‑Zhan Hong He‑Lin Gong Hong‑Jun Ji Jia‑Liang Lu Han Li Qing Li Paris Elite institute of Technology Shanghai Jiao Tong UniversityShanghai 200240China Science and Technology on reactor System Design Technology Laboratory Nuclear Power Institute of ChinaChengdu 610041China

Accurate and efficient online parameter identification and state estimation are crucial for leveraging digital twin simulations to optimize the operation of near-carbon-free nuclear energy *** previous studies,we developed a reactor operation digital twin(RODT).However,non-differentiabilities and discontinuities arise when employing machine learning-based surrogate forward models,challenging traditional gradient-based inverse methods and their *** study investigated deterministic and metaheuristic algorithms and developed hybrid algorithms to address these *** efficient modular RODT software framework that incorporates these methods into its post-evaluation module is presented for comprehensive *** methods were rigorously assessed based on convergence profiles,stability with respect to noise,and computational *** numerical results show that the hybrid KNNLHS algorithm excels in real-time online applications,balancing accuracy and efficiency with a prediction error rate of only 1%and processing times of less than 0.1 ***,algorithms such as FSA,DE,and ADE,although slightly slower(approximately 1 s),demonstrated higher accuracy with a 0.3%relative L_2 error,which advances RODT methodologies to harness machine learning and system modeling for improved reactor monitoring,systematic diagnosis of off-normal events,and lifetime management *** developed modular software and novel optimization methods presented offer pathways to realize the full potential of RODT for transforming energy engineering practices.

关键词： Parameter identification State estimation reactor operation digital twin Reduced order model Inverse problem

Photoluminescence and ratiometric thermo-response of Eu^(2+)and Eu^(3+)in BaAl_(2)B_(2)O_(7):Eu^(2+),Eu^(3+)phosphor materials

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Journal of Rare Earths 2024年第7期42卷 1240-1249,I0002页

作者： Ziyao Wang Haitao Fu Xiufeng Zhan Bo Tong Guofeng Ma H.T.(Bert)Hintzen institute of Innovative Science and Technology Shenyang UniversityShenyang110044China College of Mechanical Engineering Shenyang UniversityShenyang110044China Faculty of Applied Sciences Delft University of Technology2629 JBDelftthe Netherlands

A novel Eu^(2+)-Eu^(3+)co-activated ratiometric thermo-sensitive phosphor was developed and synthesized by solid-state *** valence state of Eu,photoluminescence and thermo-sensitive performance of the phosphor prepared either in ambient air or carbothermally were investigated and *** phosphor shows high sensitivity(Sa=0.0173 K^(-1),S_(r)=0.461%/K)and superior signal discriminability(Δν∼10380 cm^(−1)).The thermo-sensitive performance is subject to the dual effects of different thermo-responses by Eu^(2+)versus Eu^(3+)combined with energy transfer from Eu^(2+)to Eu^(3+),so that the sensitivity of the phosphor in the temperature range presents a non-monotonic *** development of the BaAl_(2)B_(2)O_(7):Eu^(2+),Eu^(3+)phosphor is not only expected to be relevant for application in the field of temperature sensing,but also of reference significance for improving the sensitivity by means of energy transfer between co-activator ions over a wider temperature range of Eu^(2+)-Eu^(3+)co-activated ratiometric thermo-sensitive phosphors.

关键词： Photoluminescence Ratiometric thermo-response Phosphor Eu^(2+)/Eu^(3+) Rare earths

Molecular dynamics study of primary radiation damage in TiVTa concentrated solid-solution alloy

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Chinese Physics B 2024年第3期33卷 530-535页

作者：赵永鹏豆艳坤贺新福曹晗王林枫邓辉球杨文 reactor Engineering Technology Research Division China Institute of Atomic EnergyBeijing 102413China School of Physics and Electronics Hunan UniversityChangsha 410082China

The primary radiation damage in pure V and TiVTa concentrated solid-solution alloy(CSA)was studied using a molecular dynamics *** have performed displacement cascade simulations to explore the generation and evolution behavior of irradiation *** results demonstrate that the defect accumulation and agglomeration in TiVTa CSA are significantly suppressed compared to pure *** peak value of Frenkel pairs during cascade collisions in TiVTa CSA is much higher than that in pure V due to the lower formation energy of point ***,the longer lifetime of the thermal spike relaxation and slow energy dissipation capability of TiVTa CSA can facilitate the recombination of point *** defect agglomeration rate in TiVTa CSA is much lower due to the lower binding energy of interstitial clusters and reduced interstitial ***,the occurrence probability of dislocation loops in TiVTa CSA is lower than that in pure *** reduction in primary radiation damage may enhance the radiation resistance of TiVTa CSA,and the improved radiation tolerance is primarily attributed to the relaxation stage and long-term defect evolution rather than the ballistic *** results can provide fundamental insights into irradiation-induced defects evolution in refractory CSAs.

关键词： concentrated solid-solution alloy primary radiation damage molecular dynamics simulation

Effect of Temperature and Grain Boundary on Void Evolution in Irradiated Copper:A Phase-Field Study

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Acta Metallurgica Sinica(English Letters) 2024年第9期37卷 1621-1632页

作者： Qionghuan Zeng Yiming Chen Zhongsheng Yang Yunhao Huang Zhijun Wang Junjie Li Jincheng Wang tate Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an710072China Science and Technology On reactor Fuel and Materials Laboratory Nuclear Power Institute of ChinaChengdu610213China

The continued existence of high-energy radiation in nuclear reactors at high temperatures results in the formation of radiation-induced voids,which will further lead to inevitable swellings of polycrystalline structural components and thus premature failures.A deep understanding of the effect of temperature and grain boundary on void evolution in irradiated copper is significant for preventing this kind of ***,the phase-field method was employed to study void evolution in irradiated copper under different temperatures and grain *** results show that,due to the different sensitivities of point defect production rate and vacancy diffusion rate to temperature changes,both the nucleation-growth rate and the coarsening rate during void evolution increase first and then decrease with increasing temperature;moreover,the nucleation mechanism exhibits site-saturated nucleation at low temperatures while continuous nucleation at high *** presence of grain boundary can accelerate the emergence of void because grain boundaries can absorb more interstitials than *** finer the grain size,the stronger inhibitory effect of grain boundaries on the growth rate of void,due to the formation of void denuded zone near grain *** high temperatures,the growth rate of void in fine grains is significantly reduced due to the increase of vacancy diffusion rate and the enhancement of sink effect of grain boundary on vacancy.

关键词： Void evolution Phase-field method Temperature Grain boundary

In-situ TEM study of the effect of hydrogen-helium ratio on defect characteristics in Fe9Cr1.5W0.4Si F/M steel during H_(2)^(+)&He^(+)simultaneous irradiation

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Journal of Materials Science & Technology 2024年第6期173卷 192-201页

作者： Dewang Cui Ziqi Cao Kun He Yuanming Li Xi Qiu Guang Ran College of Energy Xiamen UniversityXiamen 361102China Fujian Provincial Nuclear Energy Engineering Technology Research Center Xiamen 361102China Science and Technology on reactor Fuel and Materials Laboratory Chengdu 610041China Nuclear Power institute of China Chengdu 610041China Science and Technology on reactor System Design Technology Laboratory Chengdu 610041China

The effect of hydrogen and helium interaction,especially H-He ratio,on the irradiation behavior of nuclear materials has not yet been ***,this is an important basis for evaluating the irradiation properties of nuclear materials and developing high irradiation resistant ***,30 keV H_(2)^(+)and He^(+)dual beams with four H-He ratios of 0:10,3:10,15:10,and 30:10 were used to irradiate the newly developed Fe9Cr1.5W0.4Si F/M steel in TEM to in-situ study the interaction and ratio effect of hydrogen and *** addition of H atoms significantly promoted the nucleation of dislocation loops and *** the early stage of irradiation,the average size and density of dislocation loops increased with the increase of H-He ***,the larger the H-He ratio,the easier it was to form a complex dislocation ***,the final saturation size of bubbles increased with the increase of H-He *** was first found that the swelling was affected by H concentrations,with high H concentrations slowing down the increase in *** a certain irradiation dose,a specific H-He ratio would lead to a swelling peak of Fe9Cr1.5W0.4Si F/M *** super-sized bubbles at grain boundaries(GBs)were found after H addition,resulting in a bigger swelling of GBs than the *** the swelling of the GBs and the matrix show a dependence on the H-He *** current work is of great significance for understanding the interaction between hydrogen and helium in nuclear materials.

关键词： Dose ratio effect Ferritic-martensitic steel Hydrogen&helium synergetic irradiation In-situ TEM

Abnormal grain growth induced byδ→γphase transformation in Fe-based shape memory alloys

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Journal of Materials Science & Technology 2024年第5期172卷 196-201页

作者： Huabei Peng Liqiu Yong Gaixia Wang Jiazhen Yan Bing Xu Yuhua Wen School of Mechanical Engineering Sichuan UniversityChengdu 610065China Science and Technology on reactor Fuel and Materials Laboratory Nuclear Power Institute of ChinaChengdu 610041China

Grain boundaries,including low-angle,high-angle,and coinci-dence boundaries,are intrinsic interfaces in polycrystalline *** heat-treatment at sufficiently high temperatures,grain boundary migration occurs because the grain boundaries are ther-modynamically ***,grain growth occurs due to a decrease in grain boundary area after heat-treatment[1].In general,there are two types of grain growth:normal grain growth,where grains grow uniformly,and abnormal grain growth,where one or a few grains selectively grow and engulf surround-ing smaller grains,leading to the formation of large grains,some-times several millimeters or greater in size[2].The classical tech-nique to achieve abnormal grain growth is the strain-annealing method,which involves subjecting the material to a small strain followed by annealing[3,4].This method has been reported to ob-tain single-crystal wires or plates[1].Additionally,abnormal grain growth can be achieved by plastic straining at high temperatures,resulting in the fabrication of large grains or single crystals[5].However,the above methods are not applicable to components with complicated shapes due to the inevitable deformation ***,Omori et *** a simply method of abnor-mal grain growth to fabricate ultra-large grains,even single crys-tals,in Cu-Al-Mn[1],Fe-Mn-Al-Ni[2],and Fe-Mn-Al-Ni-Cr[6]*** method involves applying cyclic heat treatment between a high temperature BCC single-phase region and a low tempera-ture BCC+FCC two-phase region[1,2,6-12].Note that the cyclic heat treatment resulted in the formation of BCC sub-grain struc-tures responsible for abnormal grain growth[1,2,6-12].In addition,Yang et *** that abnormal grain growth occurred at above 900℃,and large-grains,even single crystals,were obtained only through annealing cast Cu-based polycrystalline alloys contained coherent nano-particles[13,14].Notably,the cyclic heat treatment and annealing cast alloys are deform

关键词： grain alloys deformation

High-resolution neutronics model for ^(238)Pu production in high-flux reactors

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Nuclear Science and Techniques 2024年第5期35卷 226-236页

作者： Qing-Quan Pan Qing-Fei Zhao Lian-Jie Wang Bang-Yang Xia Yun Cai Jin-Biao Xiong Xiao-Jing Liu School of Nuclear Science and Engineering Shanghai Jiao Tong UniversityShanghai 200240China Science and Technology on reactor System Design Technology Laboratory Nuclear Power Institute of ChinaChengdu 610200China

We proposed and compared three methods(filter burnup,single energy burnup,and burnup extremum analysis)to build a high-resolution neutronics model for 238Pu production in high-flux *** filter burnup and single energy burnup methods have no theoretical approximation and can achieve a spectrum resolution of up to~1 eV,thereby constructing the importance curve and yield curve of the full energy *** burnup extreme analysis method combines the importance and yield curves to consider the influence of irradiation time on production efficiency,thereby constructing extreme *** three curves,which quantify the transmutation rate of the nuclei in each energy region,are of physical significance because they have similar distributions.A high-resolution neutronics model for ^(238)Pu production was established based on these three curves,and its universality and feasibility were *** neutronics model can guide the neutron spectrum optimization and improve the yield of ^(238)Pu by up to 18.81%.The neutronics model revealed the law of nuclei transmutation in all energy regions with high spectrum resolution,thus providing theoretical support for high-flux reactor design and irradiation production of ^(238)Pu.

关键词： ^(238)Pu Neutronics model High-flux reactor Spectrum resolution Spectrum optimization

Designing ultrastrong and thermally stable FeCrAl alloys with the fine-grained structure

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Journal of Materials Science & Technology 2024年第4期171卷 198-208页

作者： Shuaiyang Liu Jinyu Zhang Hui Wang Gang Liu Xiangdong Ding Jun Sun State Key Laboratory for Mechanical Behavior of Materials Xi’an Jiaotong UniversityXi’an 710049China Science and Technology on reactor Fuel and Materials Laboratory Nuclear Power Institute of ChinaChengdu 610041China

Designing microstructurally stable FeCrAl alloys with excellent strength-ductility synergy is highly desir-able for their engineering ***,due to the preference nucleation of precipitates at grain boundaries(GBs),the improved precipitation strengthening of these alloys is usually accompanied by in-tergranular ***,we propose a novel thermomechanical processing route coupled with the Si alloying strategy via precipitation of coherent deformable Laves precipitates inside equiaxed fine-grains to achieve FeCrAl alloys with ultrahigh yield strength over∼992 MPa,excellent uniform elongation of∼7.6%at room temperature,and superior thermal stability at temperature∼1200℃.The Si alloying not only decreases the stacking fault energy of Laves precipitates favorable for their stacking-fault-mediated deformation but also hinders grain coarsening at 1200℃due to the Si-enrichment favorable for GB pin-ning *** results prove the possibility of achieving the collaborative enhancement of mutually exclusive properties in alloys,such as strength-ductility-thermal stability via nanoprecipitation engineer-ing,and offer a promising route to prepare dispersion-strengthened materials.

关键词： FeCrAl alloys Si alloying Mechanical properties Thermal stability Laves phase

Failure Analysis of Dissimilar Metal Welds between Ferritic Heat Resistant Steels and Austenitic Stainless Steels in Power Plant

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Chinese Journal of Mechanical Engineering 2024年第4期37卷 306-326页

作者： Xiaogang Li Junfeng Nie Xin Wang Kejian Li Haiquan Zhang institute of Nuclear and New Energy Technology Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of EducationTsinghua UniversityBeijing 100084China Department of Mechanical Engineering Tsinghua UniversityBeijing 100084China

This study analysed the failure of dissimilar metal welds(DMWs)between ferritic heat resistant steels and austenitic stainless steels and investigated its influencing factors by means of numerical simulation,microstructure characterization and mechanical property *** the long-term high-temperature service condition in practical power plant,the DMW failure mode was along the interface between nickel-based weld metal(WM)and ferritic heat resistant steel,and the failure mechanism was stress/strain concentration,microstructure degradation and oxidation coupling acting on the *** numerical simulation results show that interface stress/strain concentration was due to the differences in coefficient of thermal expansion and creep strength,and the degree of stress/strain concentration was related to service *** ferrite band formed at the WM/ferritic steel interface was prone to cracking,attracting the fracture along the *** interface crack allowed oxidation to develop along the WM/ferritic steel *** long-term service,the interface stress/strain concentration,microstructure and oxidation all evolved,which synergistically promoted interface failure of ***,only under the long-term service of low stress conditions could trigger the interface failure of ***,long-term service would reduce the mechanical strength and plasticity of DMW.

关键词： Dissimilar metal weld Failure Interface Stress/strain concentration Microstructure Oxidation