Hasil untuk "Nuclear engineering. Atomic power"

R.A. Pitts, A. Loarte, T. Wauters et al.

To mitigate the impact of technical delays, provide a more rationalized approach to the safety demonstration and move forward as rapidly as possible to a reactor relevant materials choice, the ITER Organization embarked in 2023 on a significant re-baselining exercise. Central to this strategy is the elimination of beryllium (Be) first wall (FW) armour in favour of tungsten (W), placing plasma-wall interaction (PWI) centre stage of this new proposal. The switch to W comes with a modified Research Plan in which a first “Start of Research Operation” (SRO) campaign will use an inertially cooled, temporary FW, allowing experience to be gained with disruption mitigation without risking damage to the complex water-cooled panels to be installed for later DT operation. Conservative assessments of the W wall source, coupled with integrated modelling of W pedestal and core transport, demonstrate that the elimination of Be presents only a low risk to the achievement of the principal ITER Q = 10 DT burning plasma target. Primarily to reduce oxygen contamination in the limiter start-up phase, known to be a potential issue for current ramp-up on W surfaces, a conventional diborane-based glow discharge boronization system is included in the re-baseline. First-of-a-kind modelling of the boronization glow is used to provide the physics specification for this system. Erosion simulations accounting for the 3D wall geometry provide estimates both of the lifetime of boron (B) wall coatings and the subsequent B migration to remote areas, providing support to a simple evaluation which concludes that boronization, if it were to be used frequently, would dominate fuel retention in an all-W ITER. Boundary plasma (SOLPS-ITER) and integrated core–edge (JINTRAC) simulations, including W erosion and transport, clearly indicate the tendency for a self-regulating W sputter source in limiter configurations and highlight the importance of on-axis electron cyclotron power deposition to prevent W core accumulation in the early current ramp phase. These predicted trends are found experimentally in dedicated W limiter start-up experiments on the EAST tokamak. The SOLPS-ITER runs are used to formulate W source boundary conditions for 1.5D DINA code scenario design simulations which demonstrate that flattop durations of ∼100 s should be possible in hydrogen L-modes at nominal field and current (Ip = 15 MA, BT = 5.3 T) which are one of the principal SRO targets. Runaway electrons (RE) are considered to be a key threat to the integrity of the final, actively cooled FW panels. New simulations of RE deposition and subsequent thermal transport in W under conservative assumptions for the impact energy and spatial distribution, conclude that there is a strong argument to increase the W armour thickness in key FW areas to improve margins against cooling channel interface damage in the early DT operation phases when new RE seeds will be experienced for the first time.

阎 明洋, 胡 志良, 张 银鸿 et al.

粒子加速器束流损失产生脉冲中子辐射场，计数型中子剂量仪测量脉冲中子存在漏计数现象。为从根源上解决漏计数问题，提出了基于中子核反应电荷量校准中子反应数的探测物理模型。研究中子核反应弱电流产生的物理机制，据此研制了弱电流积分型电子学系统，并集成为脉冲中子剂量仪。在中国散裂中子源（China Spallation Neutron Source，CSNS）上的实验表明：单次脉冲中子风暴核反应数可达10³，剂量率水平覆盖μSv∙h^-1至数百mSv∙h^-1量级，并可观测ms级脉冲中子时间结构；测量值与仿真值相符性较好，两者相差<50%。目前该研究不仅填补了国内测量宽能区脉冲中子辐射剂量的技术空白，且满足了国家大科学装置的应用需求。

CHENG Linhai1, GU Haifeng1, , TANG Wei2, CHEN Bin1, SHI Yiyan1

The flow and heat transfer characteristics of helically-coiled tubes are crucial for the design of spiral tube steam generators. In this paper, the flow and heat transfer characteristics of a vertical helically-coiled tube with an inner diameter of 8.8 mm and a helical diameter of 568 mm were experimentally investigated in a wide pressure range: 0.2-14.1 MPa. The mass flow rate is 49-1 902 kg/(m2·s). The heat flux of the experimental section is 14.5-580 kW/m2. In this experiment, the flow rate of the main loop is adjusted by the valve opening, the system pressure is adjusted by the high-pressure nitrogen cylinder, the metering pump and the pressure relief valve, the inlet fluid parameters of the experimental section is adjusted by the input power of the preheater and the direct-current (DC) voltage loaded in the preheating section, and the heating heat flux is adjusted by the DC voltage loaded in the experimental section. Finally, the friction coefficients of single-phase and two-phase, as well as heat transfer coefficients of single-phase, subcooled boiling, saturated boiling and dry out under different working conditions were obtained. Comparison and analysis of the experimental results with the empirical relational formulas of recent years revealed that the empirical formulas of Akagawa’s, Hart’s, and Ito’s predicted the single-phase friction coefficients with high accuracy within ±5%. The secondary flow increases the critical Reynolds number, which is about 10 000 in this experiment. In the range of straight tube laminar flow (Re＜2 300), the influence of secondary flow is greater. When the Reynolds number increases, the energy dissipation of secondary flow to the turbulent region is much smaller than that of laminar flow region. The current empirical formula has at least 10%-20% deviation in predicting the two-phase friction coefficient and the heat transfer coefficient in different regions. The relative average deviation between the friction coefficient of the two phases and the calculation formulas of Chen, Guo, Ferraris and M-N is about ±20%, and the prediction accuracy difference between the empirical formulas of spiral tube and straight tube is not obvious. The heat transfer coefficient of single-phase water section has the smallest relative average deviation from Guo et al. empirical formula, which is 18.2%. The relative average deviation between the heat transfer coefficient of the subcooled boiling zone and Hardik’s empirical formula is the smallest, which is −21.1%. The heat transfer coefficient of saturated boiling region has the smallest relative average deviation from the modified Chen’s formula, which is 7.5%. The relative average deviation of heat transfer coefficient of dry zone from Gao’s empirical formula is the least, which is 17.9%. The results of the analysis can provide a reference for the design of helically-coiled tube steam generators.

Mohammed Saleh Alshaikh

The performance of Organic Solar Cells (OSCs) is intrinsically linked to the molecular, electronic, and structural properties of donor and acceptor materials. This study employs various machine learning techniques, namely the Generalized Regression Neural Network (GRNN), Support Vector Machine (SVM), and Tree Boost, to predict key performance metrics of OSCs, including power conversion efficiency (PCE), short-circuit current density (JSC), open-circuit voltage (VOC), and fill factor (FF). The models are trained and evaluated using an experimentally reported dataset compiled by Sahu et al. Correlation analysis demonstrates that material characteristics such as polarizability, bandgap, dipole moment, and charge transfer are statistically associated with OSC performance. The predictive performance of the GRNN model is compared with that of the SVM and Tree Boost models, showing consistently lower prediction errors within the considered dataset. In addition, sensitivity analysis is performed to assess the relative importance of the predictor variables and to examine the influence of kernel functions on GRNN performance. The results indicate that machine learning models, particularly GRNN, can serve as effective data-driven tools for predicting the performance of organic solar cells and for supporting computational screening studies.

Xiao-jie LI, Kai-xuan TAN, Long-cheng LIU et al.

Granite is considered an ideal medium for geological disposal of nuclear waste due to its unique stability and wide distribution. When the repository media barrier fails, granite serves as the peripheral rock medium. The porous nature of intact granite in the deep subsurface provides a basis for groundwater storage and radionuclide migration, allowing radionuclides to migrate and diffuse to the biosphere along with groundwater flow, ultimately affecting the ecological environment. In this study, an advection-dispersion model for primary kinetic adsorption was developed, introducing a primary adsorption rate coefficient β to describe the kinetic adsorption phenomenon. The model also considered important mechanisms affecting the movement of nuclide ions, including electromigration, electroosmosis, and dispersion. Using the Laplace transform, combined with the nonlinear adsorption process of the nuclide ion tracer between solid-phase granite and liquid-phase water-saturated pores, the first-order reversible kinetic reaction equation was introduced into the total continuity equation to obtain an analytical solution for the standardized concentration of nuclides in the intact granite porous medium. The computational program was coded in MATLAB. The non-adsorbed nuclides I− and the moderately strongly adsorbed nuclides Sr2+ were selected as the analytical objects during the simulation process. The diffusion and adsorption in the matrix domains of the studied granite rock samples were analyzed in conjunction with basic parameters such as the porosity and the dry weight of the studied granite rock samples to obtain the relevant key migration parameters. The conclusions of this study are as follows: (1) The new model is based on the advection-dispersion model with linear adsorption and introduces a first-order adsorption rate coefficient β. The first-order adsorption kinetic advection-dispersion model has been successfully established. (2) The sensitivity analysis of the new model proves that the primary adsorption rate coefficient β affects the output of the model. When the partition coefficient Kd between the solution phase and the solid phase is fixed and β is large to a certain extent, the new model reaches a linear adsorption state. (3) Using this model to analyze the electromigration experimental data of I− and Sr2+, the \begin{document}$D_{\mathrm{m}}^{\mathrm{e}} $\end{document} of I− without electric field is （2.25±0.35）×10−14 m2/s, and the \begin{document}$D_{\mathrm{m}}^{\mathrm{e}} $\end{document} of Sr2+ without electric field is （4.80±0.31）×10−13 m2/s. Additionally, this model can estimate the first-order adsorption rate coefficient β, and explain the adsorption retardation mechanism of nuclide ions in intact granite. By analyzing the slope and curvature of the breakthrough curve, the migration mechanism of nonlinear adsorption can be deeply understood.

Feiyan Dong, Shi Chen, Kazuyuki Demachi et al.

Khalil A. Alruwaitee

Predictions on stock market prices are a noble task owing to huge complex, dynamic, and chaotic surroundings. Fast ups and downs arise in the stock market due to influences from foreign merchandise, such as sensitive political, stockholder, economic, and emotional behaviour. In the stock market, incessant unsettlement is the main reason why financiers give away at the wrong time and frequently fail to get a profit. While financing in the stock market, the stakeholders should not disremember the gamble of payment rule and reveal their assets to greater dangers. Discovering economic time series data and exhibiting the relationship between the stock trend and past data is the main method to resolve the issue. Machine learning (ML), a conventional technique, has also been considered for its ability to predict financial markets. This manuscript proposes a new Predicting Stock Price Movements with Combined Deep Learning Models and Two-Tier Metaheuristic Optimization (PSPMCDL-TTMO) method. The PSPMCDL-TTMO methodology employs an optimal deep learning model to forecast stock price movements, determining whether prices will rise or fall. At the primary stage, the PSPMCDL-TTMO model utilizes data pre-processing using Z-score normalization to ensure that the input features are standardized for consistent performance. For feature selection (FS), the dingo optimizer algorithm (DOA) is employed to optimize the most relevant and impactful features from historical stock data. In addition, the multi-head attention bi-directional gated recurrent unit (MHA-BiGRU) model is used for stock price movement prediction. Finally, the hyperparameter range of the MHA-BiGRU model is implemented by the design of the equilibrium optimizer (EO) model. The experimentation outcome analysis of the PSPMCDL-TTMO approach takes place, and the results are inspected using various features. The investigational validation of the PSPMCDL-TTMO technique attained a superior CORR value of 0.9999 over existing models.

Ruijing Li, Peng Gao, Mengyan Dai et al.

Preclinical research has established X-ray-induced photodynamic therapy (X-PDT) as a highly acknowledged antitumor therapy. X-rays play an important role in the X-PDT process. It is crucial to understand the impact of both the total dose and dose fractionation on the effectiveness of X-PDT. For the first time, a systematic study has been conducted on the effects of radiation dose and dose fractionation mode on the efficacy of X-PDT deeply. In vitro and in vivo results showed that there is an optimum dose threshold for the anti-tumor efficacy of X-PDT within the range of 0–6 Gy radiation dose. Additionally, the anti-tumor effect of a single exposure mode is significantly superior to that of a hyperfractionated radiation mode in 4T1 tumor-bearing mice. Notably, X-PDT significantly inhibited the invasion and migration of tumor cells and significantly inhibited lung metastasis of breast cancer. These new findings are significant for the clinical application of X-PDT and offer valuable insights for the development of future X-PDT radiation plans.

LI Lei, LIU Wei, MA Yuhua et al.

BackgroundExtraction of carbon from water is a crucial preprocessing step for measuring 14C in environmental waters using liquid scintillation spectrometry.PurposeThis study aims to explore the optimal technological conditions for extracting carbon from water using wet oxidation method.MethodsA wet oxidation system combining sodium persulfate and Fenton's reagent, along with phosphoric acid acidification and nitrogen bubbling, were employed for the wet oxidation carbon extraction experiments on two types of water samples with known (deionized water + sucrose) and unknown carbon components, each with a volume of 10 L. Simultaneously, carbon extraction experiments were conducted on the water samples having unknown carbon component, using a combination of wet oxidation and 185 nm ultraviolet (UV) oxidation so as to determine the optimal timing and sequence of reagent addition, as well as the optimized reagent dosage and ratio. Further experiments under optimized conditions were conducted to obtain more results for deep analysis.ResultsUnder the optimized conditions, after a 3-h reaction at 90 °C, the organic carbon extraction rate for the known carbon component (deionized water + sucrose) exceeds 96%. The total carbon extraction rate from the unknown carbon component water is (96.8±0.3)%, with an inorganic carbon extraction rate >98.5%, and an organic carbon extraction rate of (93.4±0.2)%, while the oxidation rate of tannic acid-type organic compounds is only (88±0.2)%. After the combination of wet oxidation and 185 nm UV oxidation, the total carbon extraction rate for the unknown carbon component increases to (98.3±0.5)%, with an inorganic carbon extraction rate ≥99% and an organic carbon extraction rate that can reach (95.6±1.4)%.ConclusionsResults of this study indicate that wet oxidation alone cannot represent the carbon recovery rate in actual water samples using typical organic compound carbon recovery rates. The combination of wet oxidation and 185 nm UV oxidation proves to be a more effective method for carbon extraction from water.

Fei Xiong, Jian Jiang, Yu-tong Li et al.

Purpose: To explore the feasibility of using wide-body detector Computed Tomography (CT) combined with Cardiac Motion Correction (CMC) technology for coronary Computed Tomography angiography (CCTA) in free breathing state and its impact on image quality. Methods: 120 patients who underwent CCTA scans at our institution from March 2023 to December 2023 were collected in this retrospective study. Recorded the coronary artery images before applying CMC technology as the control group, and the images after applying CMC technology as the experimental group. Patients were divided into two groups by different heart rate (HR), Group A (HR > 70 bpm) and Group B (HR ≤ 70 bpm), with 66 patients in group A and 54 patients in group B. Subjective image quality assessments were performed on the left anterior descending artery (LAD), left circumflex artery (LCX), and right coronary artery (RCA) proximal segments. These assessments were conducted by two senior radiologists using a double-blind approach and a 4-point scale (1 indicating poor image quality and 4 indicating excellent image quality). The subjective scores among the three coronary artery segments were analyzed by chi-square test, using Kappa coefficient to analyze the inter-observer agreement. Results: The control group had a subjective score of 3.37 ± 0.81/3.27 ± 0.83 for the LCX, 2.97 ± 0.85/2.93 ± 0.78 for the LAD, and 2.70 ± 0.75/2.80 ± 0.66 for the RCA. The experimental group had a subjective score of 3.90 ± 0.31/3.83 ± 0.38 for the LCX, 3.83 ± 0.38/3.87 ± 0.35 for the LAD, and 3.87 ± 0.35/3.83 ± 0.38 for the RCA. There was a great enhancement in the image quality observed in the experimental group when contrasted with the control group both in group A and group B (all P < 0.05). The inter-observer consistency of LCX, LAD and RCA were 0.726, 0.801 and 0.734 in control group and 0.769, 0.870 and 0.870 in experimental group. Conclusion: The utilization of CMC technology significantly enhances the quality of CCTA images acquired during free breathing.

WU Pan, OUYANG Zeyu, ZHU Yu et al.

BackgroundThe kilowatt reactor using stirling technology (KRUSTY) is a heat-pipe-cooled reactor experimental system that uses a Stirling engine to convert thermal energy to electricity, it is the only one published experimental data for heat-pipe-cooled reactor systems. The KRUSTY experimental data under different working scenarios include the cold startup and load change processes, heat pipe failure, reactivity insertion, and heat sink loss.PurposeThis study aims to validate the self-developed system transient analysis code named TAPIRS-D for the heat-pipe-cooled reactor concept using KRUSTY experimental data.MethodsFirstly, an in-house system code for a heat-pipe-cooled reactor named TAPIRS-D was introduced, with the main theoretical module briefly explained, including the reactor power calculation module, heat transfer module for fuel assembly, and heat pipes. Then, the TAPIRS-D was applied for the first time to the simulation of the key processes of the KRUSTY prototypic reactor test under normal operation and accident conditions. Finally, comparison between the simulation data and experimental data was conducted for the validation of this analysis code.ResultsComparison results demonstrate that the maximum relative prediction error for the fuel temperature is less than 2%, and the reactor power average prediction error is less than 10%.ConclusionsThe prediction trend of the numerical simulation by TAPIRS-D fits well with the experimental data on key parameters such as core power and the temperature of fuel and heat pipes, which indicates that TAPIRS-D is well developed and is capable of conducting safety analysis for heat pipe cooled reactor concepts. The validation of this system analysis code provides a good reference for other newly developed system codes for heat pipe reactors.

Bingchen Li, Jiaguan Peng, Bowen Xue et al.

Previous experimental studies have demonstrated that the recrystallization in nuclear materials is very sensitive to the annealing temperature, dislocation density, and original grain morphology. However, the synergistic effect of these intrinsic and extrinsic factors on recrystallization has been rarely studied due to the elevated temperatures of recrystallization and the costliness of experiments, especially in tungsten (W). In the present work, we have developed an approach that combines a phase-field model with the physics-based classical nucleation theory to study the synergistic impact of these factors on the recrystallization process. We systematically investigate the synergistic effect of annealing temperature, dislocation density, and original grain morphology on the recrystallization rate and the average recrystallized grain size. The simulation results show that increasing the dislocation density and the annealing temperature can effectively reduce the average grain size after full recrystallization. For an annealing temperature above 1523 K, the recrystallization rates have minor changes with increasing the dislocation density and annealing temperature. Furthermore, we employ an empirical model to quantitatively calculate the Vickers hardness of deformed W during the recrystallization process based on the phase-field microstructures. Notably, columnar grain crystals are found to be more effective in reducing irradiation hardness than isometric grain crystals. We believe that these simulations can provide a valuable reference for the preparation and design of radiation-resistant W materials.

Martin Schulc, Michal Košťál, Evžen Novák et al.

Lead is an important material, both for fusion or fission reactors. The cross sections of natural lead should be validated because lead is a main component of lithium-lead modules suggested for fusion power plants and it directly affects the crucial variable, tritium breeding ratio. The presented study discusses a validation of the lead transport libraries by dint of the activation of carefully selected activation samples. The high emission standard 252Cf neutron source was used as a neutron source for the presented validation experiment. In the irradiation setup, the samples were placed behind 5 and 10 cm of the lead material. Samples were measured using a gamma spectrometry to infer the reaction rate and compared with MCNP6 calculations using ENDF/B-VIII.0 lead cross sections. The experiment used validated IRDFF-II dosimetric reactions to validate lead cross sections, namely 197Au(n, 2n)196Au, 58Ni(n,p)58Co, 93Nb(n, 2n)92mNb, 115In(n,n')115mIn, 115In(n,γ)116mIn, 197Au(n,γ)198Au and 63Cu(n,γ)64Cu reactions. The threshold reactions agree reasonably with calculations; however, the experimental data suggests a higher thermal neutron flux behind lead bricks. The paper also suggests 252Cf isotropic source as a valuable tool for validation of some cross-sections important for fusion applications, i.e. reactions on structural materials, e.g. Cu, Pb, etc.

Gennady V. Arkadov, Vladimir I. Pavelko, Vladimir P. Povarov et al.

The insufficiently studied issues of acoustic standing waves (ASW) in the main circulation circuits of the VVER reactor plants are considered. For a long time no proper attention has been given to this phenomenon both by the researchers and NPP experts. In general, generation of ASWs requires the acoustic inhomogeneities of the medium in the planes perpendicular to the direction of propagation of the longitudinal wave, in which a jump in acoustic resistance occurs, this is shown by the authors based on an example of the wave equation solution (D’Alembert equation) for a certain function of two variables. The ASW classification has been developed based on the obtained experimental material, 6 ASW types have been described, and their key parameters have been specified. The amplitude distributions have been plotted for all major ASW types proceeding from the phase relations of signals from the pressure pulsation detectors and accelerometers installed on the MCC pipelines. The nature of these distributions is general and they are valid for all VVER types. For the first time the globality of all lowest ASW types is identified. Four attribute properties of the ASWs have been formulated. The first attribute is the regular ASW temperature dependences, which is the source of the diagnostic information in the process of heating/cooling of the VVER unit. The linear experimental dependences of the ASW frequencies on coolant temperature have been obtained. The frequencies, at which the MCC resonant excitation due to coincidence of the ASW frequencies with the RCP rotational frequency harmonics, have been found experimentally. The ASW energy, which origin has resulted from the RCP operation, is estimated. The RCP operation can be presented as continuous generation of pressure pulsations, which fall onto the acoustic path inhomogeneities in the form of a traveling wave and generate a standing wave after reflection from them.

Da Tao, Zhaopeng Liu, Xiaofeng Diao et al.

Demographics, personality traits and attitudes are related to safety behaviors in varied workplaces, but their roles in nuclear power plants (NPPs) have not been fully understood. This study was conducted to explore the roles of a set of demographic, personality and attitudinal factors on self-reported safety behaviors (including safety participation and human errors) among NPP commissioning workers. Survey data were collected from 157 Chinese commissioning workers. Results showed that age and work experience were significantly associated with human errors, but not with safety participation. Neuroticism and conscientiousness were significantly related to human errors, while neuroticism, conscientiousness and agreeableness were significantly related to safety participation. Attitude towards questioning was observed as an antecedent of safety participation, and functioned as a mediating variable in the relation between conscientiousness and safety behaviors. The findings provide evidence-based implications on the design of diverse interventions and strategies for the promotion of safety behaviors in NPPs.

FAN Xinyang, WANG Min, HONG Xu et al.

BackgroundDigital shaping algorithms are widely applied to improving the energy resolution of digital nuclear instruments.PurposeThis work aims to improve and analyze the performance of cusp-like shaping algorithm for digital nuclear signal with emphasis on the influence of shaping parameters on the shape of the shaped pulse.MethodsBased on the peak pulse forming algorithm, flat-top parameter was introduced into cusp-like pulse shaping algorithm. The fast silicon drift detector (FAST-SDD) detector produced by Amptek company was employed to measure the pulse signal obtained from manganese sample, the effect of shaping parameters on the shape of the output signal and the separation of pile-up pulses were investigated by the cusp-like pulse shaping method, and compared with the common trapezoidal pulse shaping methods. In addition, Cusp-like shaping and trapezoidal pulse shaping were used for the sampled nuclear pulse signals, and then amplitude discrimination was performed to obtain energy spectrum information. Finally, the influences of the two methods on the counting rate and energy resolution of the same time were studied.ResultsThe results show that the cusp-like pulse shaping has a fast falling edge and a narrow pulse width, makes it easier to separate the pile-up pulses than triangle pulse shaping.ConclusionsUnder the same peak time, trapezoidal pulse shaping has more advantages in energy resolution than cusp-like shaping, while cusp-like pulse shaping shows better performance in count rate.

Rochman Dimitri, Vasiliev Alexander, Ferroukhi Hakim et al.

The Mixed Oxide samples (MOX) ARIANE Post Irradiation Examination samples BM1 and BM3 have been analyzed in this work, based on various two- and three-dimensional models. Calculated and measured nuclide inventories are compared based on CASMO5, SIMULATE and SNF simulations, and calculated values for the decay heat of the assembly containing the samples are also provided. For uncertainty propagation, the covariance information from three different nuclear data libraries are used. Uncertainties from manufacturing tolerances and operating conditions are also considered. The results from these two samples are compared with the ones from two UO2 samples, namely GU1 and GU3, also from the ARIANE program, applying the same calculation scheme and uncertainty assumptions. It is shown that a two-dimensional assembly model provides better agreement with the measurements than a two-dimensional single pin model, and that the full core three-dimensional model provides similar results compared to the assembly model, although no 148Nd normalization is applied for the full core model. For the MOX assembly decay heat, as expected, heavy actinides have a higher contribution compared to the cases with the UO2 samples; additionally, decay heat uncertainties are moderately smaller in the case of the MOX assembly.

Kab-Mun Cha, Hyun-Chul Lee

In this paper, we propose a novel method to quantify the neural synchronization between subjects in the collaborative process through electroencephalogram (EEG) hyperscanning. We hypothesized that the neural synchronization in EEGs will increase when the communication of the operators is smooth and the teamwork is better. We quantified the EEG signal for multiple subjects using a representative EEG quantification method, and studied the changes in brain activity occurring during collaboration. The proposed method quantifies neural synchronization between subjects through bispectral analysis. We found that phase synchronization between EEGs of multi subjects increased significantly during the periods of collaborative work. Traditional methods for a human error analysis used a retrospective analysis, and most of them were analyzed for an unspecified majority. However, the proposed method is able to perform the real-time monitoring of human error and can directly analyze and evaluate specific groups. Keywords: Human error, EEG, Hyperscanning, Bispectral analysis