分类： 物理学 >> 核物理学 提交时间： 2023-11-29 合作期刊: 《Nuclear Science and Techniques》
摘要：The phenomenology involved in severe accidents (SA) in nuclear reactors is highly complex. Currently, integrated analysis programs used for severe accident analysis heavily rely on custom empirical parameters, which introduce considerable uncertainty. Therefore, in recent years, the field of severe accidents has shifted its focus toward applying uncertainty analysis methods to quantify uncertainty in safety assessment programs, known as "best estimate plus uncertainty (BEPU)." This approach aids in enhancing our comprehension of these programs and their further development and improvement. This study concentrates on a third-generation pressurized water reactor (Gen-III PWR) equipped with advanced active and passive mitigation strategies. Through an Integrated Severe Accident Analysis Program (ISAA), numerical modeling and uncertainty analysis were conducted on severe accidents resulting from large break loss of coolant accidents (LBLOCA). Seventeen uncertainty parameters of the ISAA program were meticulously screened. Using Wilks' formula, the developed uncertainty program code, SAUP, was employed to carry out Latin hypercube sampling (LHS), while ISAA was employed to execute batch calculations. Statistical analysis was then conducted on two figures of merit (FOMs), namely, hydrogen generation and the release of fission products (FP) within the pressure vessel. Uncertainty calculations revealed that hydrogen production and the fraction of fission product released exhibited a normal distribution, ranging from 182.784 kg to 329.581 kg and from 15.6% to 84.3%, respectively. The ratio of hydrogen production to reactor thermal power fell within the range of 0.0578 to 0.104. A sensitivity analysis was performed for uncertain input parameters, revealing significant correlations between the failure temperature of the cladding oxide layer, maximum melt flow rate, size of the particulate debris, and porosity of the debris with both hydrogen generation and the release of fission products.
分类： 物理学 >> 核物理学 提交时间： 2023-11-25
Yijie Wang
Fenhai Guan
Qianghua Wu
Xinyue Diao
Yan Huang
Liming Lyu
Yuhao Qin
Zhi Qin
Dawei Si
Zhen Bai
Fangfang Duan
Limin Duan
Zhihao Gao
Qiang Hu
Rongjiang Hu
Genming Jin
Shuya Jin
Junbing Ma
Peng Ma
Jiansong Wang
摘要：The intensity interferometry is applied as a chronometer of the particle emission of hydrogen isotopes from the intermediate velocity source formed in $^{40}$Ar+$^{197}$Au reactions at 30 MeV/u. The dynamic emission order of $ tau_{ rm p}> tau_{ rm d}> tau_{ rm t}$ is evidenced via the correlation functions of nonidentical particle pairs. Assuming the similar source size, the same emission order is inferred from the correlation functions of identical particle pairs, where $ tau_{ rm p} approx 100 { rm ~fm/c}$ is extracted by the fit of Koonin-Pratt equation to p-p correlation function. Transport model simulations demonstrate that the dynamic emission order of light charged particles depends on the stiffness of the nuclear symmetry energy.
分类： 物理学 >> 核物理学 提交时间： 2023-11-25
Fen-Hai Guan
Xin-Yue Diao
Qiang-Hua Wu
Xiang-Lun Wei
He-Run Yang
Peng Ma
Zhi Qin
Yu-Hao Qin
Dong Guo
Rong-Jiang Hu
Li-Min Duan
Zhi-Gang Xiao
Yi-Jie Wang
摘要：The Compact Spectrometer for Heavy Ion Experiment (CSHINE) is under construction for the study of isospin chronology via the Hanbury Brown$-$Twiss (HBT) particle correlation function and the nuclear equation of state of asymmetrical nuclear matter. The CSHINE consists of silicon strip detector (SSD) telescopes and large-area parallel plate avalanche counters, which measure the light charged particles and fission fragments, respectively. In phase I, two SSD telescopes were used to observe 30 MeV/u $^{40}$Ar +$^{197}$Au reactions. The results presented here demonstrate that hydrogen and helium were observed with high isotopic resolution, and the HBT correlation functions of light charged particles could be constructed from the obtained data.
分类： 物理学 >> 核物理学 提交时间： 2023-11-25 合作期刊: 《原子核物理评论》
摘要：本工作基于国产𝜙2″ ×2″ LaBr3(Ce) 晶体耦合滨松R13089 型快时间响应光电倍增管定制了LaBr3(Ce) 探测器。研究结果表明，定制LaBr3(Ce) 快时间探测器对662 keV 𝛾 射线的能量分辨率和全能峰探测效率分别为3.6% 和0.09%，对60Co 中1173-1332 keV 级联𝛾 射线的时间分辨率为270 (22) ps。该探测器的本征辐射计数率为4824 (69) Counts/h/cm3。本文同时展示了圣戈班B380 和B390 探测器的测试结果作为参考。
分类： 物理学 >> 核物理学 提交时间： 2023-11-23
摘要：The supercritical CO2 Brayton cycle is considered a promising energy conversion system for Generation IV reactors for its simple layout, compact structure, and high cycle efficiency. Mathematical models of four Brayton cycle layouts are developed in this study for different reactors to reduce the cost and increase the thermohydraulic performance of nuclear power generation to promote the commercialization of nuclear energy. Parametric analysis, multi-objective optimizations, and four decision-making methods are applied to obtain each Brayton scheme’s optimal thermohydraulic and economic indexes. Results show that for the same design thermal power scale of reactors, the higher the core’s exit temperature, the better the Brayton cycle’s thermo-economic performance. Among the four-cycle layouts, the recompression cycle (RC) has the best overall performance, followed by the simple recuperation cycle (SR) and the intercooling cycle (IC), and the worst is the re-heating cycle (RH). However, RH has the lowest total cost of investment (Ctot) of $1619.85 million, and IC has the lowest levelized cost of energy (LCOE) of 0.012$/(kWh). The nuclear Brayton cycle system’s overall performance has been improved due to optimization. The performance of the Molten Salt Reactor combined with the intercooling cycle (MSR-IC) scheme has the greatest improvement, with the net output power (Wnet), thermal efficiency ηt, and exergy efficiency (ηe) improved by 8.58%, 8.58%, and 11.21% respectively. The performance of the Lead-cooled Fast Reactor combined with the simple recuperation cycle scheme was optimized to increase Ctot by 27.78%. In comparison, the internal rate of return (IRR) increased by only 7.8%, which is not friendly to investors with limited funds. For the nuclear Brayton cycle, the Molten Salt Reactor combined with the recompression cycle scheme should receive priority, and the Gas-cooled Fast Reactor combined with the re-heating cycle scheme should be considered carefully.
分类： 物理学 >> 核物理学 提交时间： 2023-11-22 合作期刊: 《Nuclear Science and Techniques》
摘要：
分类： 物理学 >> 核物理学 提交时间： 2023-11-22 合作期刊: 《Nuclear Science and Techniques》
Qin Xu
Hua-Ting Kong
Ke Liu
Huan Zhou
Kun-Hao Zhang
Wei-Wei Wang
Min-Jun Li
Qiang-Yan Pan
Xing-Ya Wang
Yu-Zhu Wang
Feng Yu
Xing-Yu Gao
Qi-Sheng Wang
摘要：BL10U2 is an undulator-based macromolecular crystallography (MX) beamline located at the 3.5-GeV Shanghai Synchrotron Radiation Facility. BL10U2 is specifically designed for conducting routine and bio safety level-2 (BSL-2) MX experiments utilizing high-flux tunable X-rays with energies from 7 to 18 keV, providing a beam spot size of 20 µm (horizontal) × 10 µm (vertical) at the sample point. Certification by the Shanghai Pudong Municipal Health Commission confirmed the capability to perform BSL-2 MX experiments. The beamline is currently equipped with an Eiger X 16M detector and two newly developed in-house high-precision diffractometers that can be switched to perform conventional or in situ crystal diffraction experiments. An automatic sample changer developed in-house allows fast sample exchange in less than 30s, supporting high-throughput MX experimentation and rapid crystal screening. Data collection from both the diffractometer and detector was controlled by an in-house developed data collection software (Finback) with a user-friendly interface for convenient operation. This study presents a comprehensive overview of the facilities, experimental methods, and performance characteristics of the BL10U2 beamline.
分类： 物理学 >> 核物理学 提交时间： 2023-11-21 合作期刊: 《Nuclear Science and Techniques》
Liangliang Wang
Jianing Dong
Mingyi Dong
Qinglin Geng
Min Luo
Yan Niu
Anqing Wang
Chenxu Wang
Meng Wang
Lei Zhang
Liang Zhang
Ruikai Zhang
Yao Zhang
Minggang Zhao
Yang Zhou
Yi Liu
Xiaocong Ai
Guangyan Xiao
Yaxuan Li
Linghui Wu
摘要：The reconstruction of the tracks of charged particles with high precision is crucial for HEP experiments to
achieve their physics goals. The BESIII drift chamber, which is used as the tracking detector of the BESIII
experiment, has suffered from aging effects resulting in degraded tracking performance after operation for ap-
proximately 15 years. To preserve and enhance the tracking performance of BESIII, one of the proposals is to
add one layer of a thin cylindrical CMOS pixel sensor based on state-of-the-art stitching technology between
the beam pipe and the drift chamber. The improvement in the tracking performance of BESIII with such an
additional pixel detector compared to that with only the existing drift chamber was studied using the modern
common tracking software ACTS , which provides a set of detector-agnostic and highly performant tracking
algorithms that have demonstrated promising performance for a few high-energy physics and nuclear physics
experiments.
分类： 物理学 >> 核物理学 提交时间： 2023-11-18 合作期刊: 《Nuclear Science and Techniques》
摘要：The estimation of model parameters is an important subject in engineering. In this area of work, the prevailing approach is to estimate or calculate these as deterministic parameters. In this study, we consider the model parameters from the perspective of random variables and describe the general form of the parameter distribution inference problem. Under this framework, we propose an ensemble Bayesian method by introducing Bayesian inference and the Markov chain Monte Carlo (MCMC) method. Experiments on a finite cylindrical reactor and a 2D IAEA benchmark problem show that the proposed method converges quickly and can estimate parameters effectively, even for several correlated parameters simultaneously. Our experiments include cases of engineering software calls, demonstrating that the method can be applied to engineering, such as nuclear reactor engineering.
分类： 物理学 >> 核物理学 提交时间： 2023-11-16
Hua Ai
Xinmei Yang
Huajian Liu
Bingchuan Chen
Ling Han
Hua Sun
Yanjun Chen
Yuan Qian
Jian-Qiang Wang
摘要：The corrosion behavior of 316H stainless steel (SS) in the impure and purified NaCl-KCl-MgCl2 salt was investigated at 700 °C . Results indicate that the main deleterious impurity induced corrosion in the impure salt was the absorbed moisture, present in the form of MgCl2·6H2O. 316H SS occurred severe intergranular corrosion with a corrosion depth of 130 μm for 1000 h in the impure NaCl-KCl-MgCl2 salt. In contrast, the purification treatment of molten chloride salt by the dissolved Mg metal can remove the absorbed moisture, and the corresponding reactions were also discussed. As a result, the corrosiveness of NaCl-KCl-MgCl2 salt is reduced significantly. 316H SS occurred slight uniform corrosion with a depth of less than 5 μm for 3000 h in the purified NaCl-KCl-MgCl2 salt.
分类： 物理学 >> 核物理学 提交时间： 2023-11-15
Ke Liu
Huan Zhou
Qin Xu
Huating Kong
Kunhao Zhang
Weiwei Wang
Minjun Li
Zhijun Wang
Qiangyan Pan
Xingya Wang
Feng Yu
Qisheng Wang
摘要：Macromolecular crystallography beamline BL17U1 at the Shanghai Synchrotron Radiation Facility has been relocated, upgraded, and given a new ID (BL02U1). It now delivers X-rays in the energy range of 6–16 keV, with a focused beam of 11.6 µm × 4.8 µm and photon flux greater than 10^12 phs/s. The high credibility and stability of the beam and good timing synchronization of the equipment significantly improve the experimental efficiency. Since June 2021, when it officially opened to users, over 4200 h of beamtime have been provided to over 200 research groups to collect data at the beamline. Its good performance and stable operation have led to the resolution of several structures based on data collected at the beamline.
分类： 物理学 >> 核物理学 提交时间： 2023-11-15
Yijie Wang
Mengting Wan
Xinyue Diao
Sheng Xiao
Yuhao Qin
Zhi Qin
Dong Guo
Dawei Si
Boyuan Zhang
Baiting Tian
Fenhai Guan
Qianghua Wu
Xianglun Wei
Herun Yang
Peng Ma
Rongjiang Hu
Limin Duan
Fangfang Duan
Junbing Ma
Shiwei Xu
摘要：The neutron rich neck zone created in heavy ion reaction is experimentally probed by the production of the $A=3$ isobars. The energy spectra and angular distributions of triton and $^3$He are measured with the CSHINE detector in $^{86}$Kr +$^{208}$Pb reactions at 25 MeV/u. While the energy spectrum of $^{3}$He is harder than that of triton, known as "$^{3}$He-puzzle", the yield ratio $R({ rm t/^3He})$ presents a robust rising trend with the polar angle in laboratory. Using the fission fragments to reconstruct the fission plane, the enhancement of out-plane $R({ rm t/^3He})$ is confirmed in comparison to the in-plane ratios. Transport model simulations reproduce qualitatively the experimental trends, but the quantitative agreement is not achieved. The results demonstrate that a neutron rich neck zone is formed in the reactions. Further studies are called for to understand the clustering and the isospin dynamics related to neck formation.
分类： 物理学 >> 核物理学 提交时间： 2023-11-14
Yijie Wang
Fenhai Guan
Dawei Si
Sheng Xiao
Boyuan Zhang
Yaopeng Zhang
Baiting Tian
Xianglun Wei
Herun Yang
Peng Ma
Rongjiang Hu
Limin Duan
Fangfang Duan
Qiang Hu
Junbing Ma
Shiwei Xu
Zhen Bai
Yanyun Yang
Jiansong Wang
Wenbo Liu
摘要：Two-body correlations of the isotope-resolved light and heavy clusters are measured in 86Kr+ 208Pb reactions at 25 MeV/u. The yield and kinetic variables of the A = 3 isobars, triton and 3He, are analyzed in coincidence with the heavy clusters of 7 ≤ A ≤ 14 emitted at the earlier chance. While the velocity spectra of both triton and 3He exhibit scaling behavior over the type of the heavy clusters, the yield ratios of t/ 3He correlate reversely to the neutron-to-proton ratio N/Z of the latter, showing the ping-pong modality of the N/Z of emitted clusters. The commonality that the N/Z of the residues keeps the initial system value is extended to the cluster emission in heavy ion reactions. The comparison of transport model calculations to the data is discussed.
分类： 物理学 >> 核物理学 提交时间： 2023-11-09 合作期刊: 《原子核物理评论》
摘要：利用神经网络模型学习、模拟随机两体系综（TBRE）下的原子核基态自旋分布，并对学习后的模型输入特征进行了分析。这是核物理中利用神经网络模型进行分类的典型应用。研究发现使用本文采用的单隐藏层神经网络模型，精确地描述每个随机相互作用系综内的样本仍比较困难。但是神经网络模型可以相对较好地描述基态自旋的统计性质。这可能是因为神经网络模型学习到了TBRE中基态自旋分布的经验规律。
分类： 物理学 >> 核物理学 提交时间： 2023-11-08
摘要：从核散裂反应中碎片分布的经验现象，构建了半经验公式来预测高能γ诱导核散裂反应（PNSR）中的碎片截面。在构建SPAGINS公式时，采用的理论模型包括TALYS工具包、SPACS和Rudstam五参数化公式，研究了入射能量在100~1000MeV之间的PNSR中碎片分布的一般现象。考虑到PNSR的主要特性，SPAGINS公式修改了EPAX和SPACS公式，有效地再现了实验测量数据。SPAGINS公式为预测PNSR中片段的产生提供了一种新的、有效的工具。
分类： 物理学 >> 核物理学 提交时间： 2023-11-04
摘要：The recent progresses on the wobbling motion are briefly introduced. So far 17 wobbling candidates have been reported in odd-$A$ and even-even nuclei that spread over $A approx 100$, 130, 160, and 190 mass regions. The two-quasiparticle configuration wobbling in $^{130}$Ba and the wobbling motion in a triaxial rotor are taken as examples in this paper to show the wobbling motion in even-even nuclei. The combination of covariant density functional theory and particle rotor model (CDFT+PRM) is a powerful theoretical method to study the wobbling motion. The time evolution of the wobbling motion is an interesting topic, from which the wobbling nature is intuitively revealed.
分类： 物理学 >> 核物理学 提交时间： 2023-11-03 合作期刊: 《原子核物理评论》
摘要：重锕系核弹靶组合的多核子转移反应可能是产生丰中子超重核的重要突破口，因此设计建造适用于多核子转移反应的丰中子超重核研究的原理性谱仪不仅可以为探索超重核稳定岛奠定技术、方法和装置基础，而且对研究多核子转移反应机制有重要意义。丰中子超重核研究原理性谱仪中的气体单元需要持续不断的高纯度氦气，以停阻多核子转移反应产物并将降能后的离子引出到后续的实验装置。论文主要介绍新研制的丰中子超重核研究原理性谱仪的气体单元低温纯化系统，此系统主要为谱仪提供可循环的高纯度氦气。经实验测定，低温纯化系统可以将99%的氦气纯化到99.999%以上，结合化学纯化单元，纯化后的氦气满足气体单元对高纯度氦气的需求。
分类： 物理学 >> 核物理学 提交时间： 2023-11-01
摘要：碳离子束治疗因其倒转的深度剂量分布和较高的相对生物学效应，具有对正常组织损伤小、副作用低等优势，有望成为头颈部肿瘤放疗的主力。剂量算法的精确性直接影响临床照射剂量的准确性，减小碳离子束治疗剂量计算误差有助于提高患者生存率和局部控制率。本文采用解析笔形束算法对5例头颈部患者病例进行碳离子束治疗剂量计算，并利用蒙特卡罗模拟方法对治疗计划进行剂量验证，对解析计算和蒙特卡罗模拟结果进行不同评价标准组合下(2%/2mm, 3%/2mm, 3%/3mm, 3%/5mm)的伽马通过率分析、DVH图及参考指标分析、中心轴剂量分布对比。结果显示：笔形束算法在3%/2mm的评价标准下平均伽马通过率为90.441%，满足碳离子束治疗头颈部肿瘤的剂量计算要求。笔形束算法在束流横向上的计算结果较为精准，但在沿束流入射方向上的计算结果受路径上组织非均匀性及空腔的影响，存在射程偏差。为降低剂量计算误差带来的影响，碳离子束治疗头颈部肿瘤时需要采用更保守的射野角度选择。本文对比结果可用于指导基于解析笔形束剂量算法的头颈部肿瘤碳离子束治疗计划设计。
分类： 物理学 >> 核物理学 提交时间： 2023-10-31
摘要：The Chinese large-area violet-light-sensitive silicon photodiode PIN is one of the candidates of the lead tungstate crystal detector readout component of the photon spectrometer in the large heavy ion collision experiment. The PIN diode was assembled with the lead tungstate crystal and the low-noise preamplifier into a complete detector unit. The beam test was carried out on the SPS accelerator at CERN. The energy resolution was measured with the electron beam energy ranging from 5 to 40 GeV. The summation correction method was discussed, and an excellent linearity of the nominal beam energy versus the peak position of the detector was obtained, which showed the punch-through effect can be ignored.
分类： 物理学 >> 核物理学 提交时间： 2023-10-31
Chengbo Li
Qungang Wen
Yuanyong Fu
Jing Zhou
Shuhua Zhou
Qiuying Meng
C. Spitaleri
A. Tumino
R. G. Pizzone
L. Lamia
摘要：The 2H(d, p ) 3H bare nucleus astrophysical S(E) factor has been measured indirectly at energies from about 500 keV down to several keV by means of the Trojan-horse method applied to the quasi#2;free process 2H(6Li, pt)4He induced at the lithium beam energy of 11 and 9.5 MeV, which makes the virtual binary process incident energy Eqf dd go much closer to the zero-quasi-free-energy point than that in the previous similar experiment. The obtained results are compared with direct data as well as with previous indirect investigation of the same binary reactions. It shows that the precision of S(E) data in low energy range extracted via the same Trojan horse nucleus ( 6Li = ( d ⊕ α) ) becomes better when the incident energy decreases from high value down to the zero-quasi-free-energy point. The very good agreement between data extracted from different Trojan horse nucleus ( 6Li = ( d ⊕ α ) vs. 3He = ( d ⊕ p)) gives a strong updated test for the independence of the binary indirect cross section on the chosen Trojan horse nucleus at low energies.
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