Science and Technology of Nuclear Installations

Yavuz, Ceyhun; Şentürk Lüle, Senem; Zhang, Han

doi: 10.1155/stni/1443278pmid: N/A

Nuclear reactors are subject to strict safety standards due to the critical nature of operational safety. Detecting transients as fast and accurately as possible is essential to reactor safety especially to reduce the human error of operators. In order to enhance this process, artificial intelligence (AI) offers strong opportunities. The robust AI systems that are validated and verified with current reactors’ data will increase the trust of AI systems for next‐generation small modular reactors. In this study, five transients of light water reactors (reactivity insertion with rod withdrawal, steam leak from pressurizer, pump trip, loss of coolant (LOCA) in the hot leg, and LOCA in the cold leg) were selected to generate 53 subscenarios by using the description of VVER‐1000 type reactor. For the 93 features of the system selected based on reactor operation, simulations produced 475.695 data points stored in 5115 rows, 4085 of which were committed to training and 1030 to the validation process. The three methods for reinforced machine learning to detect transients, K‐nearest neighbors, decision tree classifier, and random forest classifier, have been implemented. The success and failure rates of the models have also been analyzed and presented. When accuracy, precision, recall, and F1‐score are compared together, the random forest method showed the best performance.

doi: 10.1155/stni/9796736pmid: N/A

Blay, Alberta; Attakorah-Birikorang, Sylvester; Awuah, Esi; Sharma, Manish

doi: 10.1155/stni/8876882pmid: N/A

Emergency planning zones (EPZs) for Ghana’s potential reactor site have been determined based on an assessment of atmospheric dispersion and dose calculations for multiple accident scenarios involving a VVER‐1200 reactor. The analysis was performed using the Radiological Assessment System for Consequence Analysis (RASCAL) 4.3.4 code to calculate doses at a downwind distance of 80 km from the site for wet and dry depositions. The highest estimated doses, consistent with the Fukushima accident releases, were used to define the EPZs. The study identified the distances for two main EPZs: precautionary action zones (PAZs) and urgent protective zones (UPZs). The estimated PAZ is 5 km distance around the power plant, requiring evacuation of individuals before radionuclide release begins in the event of a severe accident to prevent deterministic health effects. The UPZ extends approximately 24 km downwind, necessitating the evacuation of affected individuals depending on the release conditions, with priority given to pregnant women, children, and nursing mothers to reduce stochastic health effects. Remaining individuals may need to shelter in their residences or designated centers for two days and take iodine thyroid blocking (ITB) agents within 5–64 km. These EPZs align with the International Atomic Energy Agency (IAEA) recommendations, providing a foundation for policymakers to evaluate the feasibility of proposed emergency measures in developing a robust emergency preparedness and response plan.

Zhao, Yufei; Qin, Yongquan; Zhang, Zhaoqing; Zhao, Yaping; Liu, Quanwei; Li, Li; Wang, Zhiheng; Zhang, Yadong; Heng, Jiaxi; Hou, Liudong; Xu, Kai

doi: 10.1155/stni/2388701pmid: N/A

The concentration of plutonium (Pu) is a critical parameter for process control and analysis in the PUREX process for spent fuel reprocessing. Although spectrophotometry is a well‐established technique for continuous Pu analysis, online monitoring of reprocessing samples remains a challenge. This paper introduces a novel online spectrophotometric device and methodology for the rapid determination of Pu concentration in reprocessing solutions. By capturing UV‐visible absorption spectra and implementing a specialized engineering design, the new device provides precise measurements. Experimental results show that the online spectrophotometric method can detect Pu concentrations from 1.0 to 8.0 g/L with a precision of better than 0.18% and an accuracy within 3%. The device also features integrated online cleaning and calibration capabilities, offering an innovative solution for measuring Pu concentrations in process solutions at spent fuel reprocessing facilities.

Wang, Yulu; Luan, Tian; Du, Wanqian; Zhang, Han

doi: 10.1155/stni/6617103pmid: N/A

During nuclear reactor accidents where cooling fails, fuel rod melting and subsequent molten material flow through core channels critically determine disaster progression. Using advanced particle‐based simulation (MPS) with enhanced heat transfer, surface tension, and phase‐change modeling, this study reveals: Zirconium alloy cladding undergoes complex secondary melting, unexpectedly reliquefying after initial solidification when contacting molten fuel material; meanwhile, fuel pellet melting slows after outflow while cladding degradation accelerates due to heat shifts between materials. In multirod (2 × 2) bundles, cladding melts significantly faster with less fuel resolidification due to concentrated heat from additional pellets. Crucially, initial melt volume and temperature dominate relocation behavior: larger melt amounts reduce solidification while intensifying cladding damage, whereas cooler melts increase solidification but maintain severe cladding erosion through prolonged viscous adhesion. This study establishes a critical foundation for advancing fundamental understanding of severe accident progression and expanding the application of the MPS method in nuclear safety.

Al-Shammari, Fatimah M.; Aksouh, Farouk; Al-Ayed, Mohammed S.; Ivanov, Peter

doi: 10.1155/stni/5566252pmid: N/A

The gamma camera is a nuclear medicine imaging device based on a scintillation detector. It detects gamma ray photons emitted by radionuclides injected into a patient. The camera’s spatial resolution, which is its ability to discriminate between two separate objects, is a main requirement for image quality. The intrinsic spatial resolution is the resolution of the scintillation crystal itself. It is affected by many factors, such as the type of scintillation crystal, its thickness, the energy of the primary gamma photon, and the detection efficiency. This work aims to study the intrinsic spatial resolution of a gamma camera using different scintillation materials and geometries in the energy range of 200 up to 1000 keV in a simulation study using the Geant4 program. From the results, the position measurement was determined with good accuracy, and the position improved when using the centroid method.

Abrefah, Rex G.; Zakaria, Suleman A.; Ameyaw, F.; Hanfi, Mohamed

doi: 10.1155/stni/5515993pmid: N/A

This review paper delves into Ghana’s pursuit of nuclear energy as a pivotal component for sustainable development. It highlights the potential benefits of nuclear power in bolstering energy security, stimulating economic growth and advancing environmental sustainability, framed around three core development pillars: economic progress, social advancement and environmental conservation. The paper also discusses the major challenges and critical considerations for nuclear energy adoption, such as financing nuclear projects, managing radioactive waste, upgrading the national electric grid and addressing the social and environmental risks associated with nuclear energy. Through detailed analysis, the study presents the challenges and opportunities that Ghana faces in leveraging nuclear energy for sustainable growth and offers strategic recommendations to guide policymakers and relevant stakeholders.

Wang, Mengmeng; Fang, Meihua; Wei, Zhiyong; Guo, Yi; Li, Junyu; Li, Jiafeng; Zhang, Ming; Li, Haoxuan; Cizelj, Leon

doi: 10.1155/stni/5595233pmid: N/A

This paper studies the influence of bias voltage on pulse waveform, energy resolution, and particle discrimination performance to optimize the performance of n/γ pulse shape discrimination (PSD) for plastic scintillator coupled with SiPM arrays. Experiments were carried out with the EJ‐276 plastic scintillator detection system based on 2 × 2 SiPM arrays in gamma sources (22Na, 60Co, 137Cs) and neutron source (252Cf). And the pulse amplitude, shape, and the dispersion degree of the pulse waveform with bias voltage in the range of 25.8–28.8 V were analyzed. Gauss expansion method and PSD method based on the charge integration were used to obtain accurate energy resolution and PSD parameter, respectively. The results showed that energy resolution and PSD performance improved firstly and then deteriorated as bias voltage increases, and the optimum bias voltage for both energy resolution and PSD performance was 27.6 V. Within the bias voltage range of 25.8–28.8 V, the energy resolutions at the optimal bias voltage were improved by 25.17% (0.341 MeV for 22Na source) and 22.24% (1.062 MeV for 22Na source). Additionally, the PSD performance for n/γ discrimination was improved by 19.6%.

Zhang, Ziyue; Li, Dong; Wang, Nianfeng; Lei, Meng; Zakaly, Hesham M.H.

doi: 10.1155/stni/5416943pmid: N/A

To improve the process of best estimate plus uncertainty (BEPU) for nuclear safety assessment and calibration of thermal–hydraulic models for error reduction, inverse uncertainty quantification (IUQ) is proposed in recent years to quantify the uncertainty of model parameters in reactor program. As reflooding is a vital stage to cool the core and prevent serious accidents and uncertainties exist in the important results of the program because of the complexity of the phenomena, IUQ is performed for reflooding models in this study based on Bayesian theory and Markov chain Monte Carlo (MCMC) algorithm. In order to solve the problem of large time costs in sampling and inefficient use of transient sample points, particle swarm optimization (PSO)–Kriging model and principal component analysis (PCA) are adopted in this paper. Measurement of peak cladding temperature (PCT) and quench time from FEBA and FLECHT SEASET experiments supply data for evaluation and validation. Results show that PSO–Kriging model could well represent the system program with R2 (R‐squared coefficient of determination) close to 1 and uncertainties assessed by the method could cover most of the time sequential experiment data. By comparing the methods with and without PCA, it indicates that the IUQ method utilizing PCA not only reduces input parameter correlation but also provides more accurate estimates of input parameter posterior distributions. Furthermore, the validation outcomes of mean value calibration show enhanced agreement with the experimental data.

Tan, Shiyu; Xie, Haiyan; Chen, Shuang; Wang, Ke; Liu, Shitao; Li, Dongyun; Li, Jing; Gao, Yang; Hou, Hongguo; Jiao, Caishan; Chao, Nan; Liu, Tingting; Zhou, Yu; Biswas, Arnab

doi: 10.1155/stni/9993615pmid: N/A

In order to reduce the negative impact of corrosion products on the operation of pressurized water reactors (PWRs) and to provide support for the operation and failure analysis of the purification resin in the first circuit of the PWRs, this paper takes the mixed‐bed ion exchange (MBIE) column as the research object. A multicomponent MBIE column model based on film diffusion control is adopted to investigate the corrosion product removal. The effects of temperature, flow rate and resin particle diameter on the effluent concentration, saturation adsorption time and resin loading of ionic corrosion products (Fe2+, Mn2+, Zn2+, etc.) are investigated in detail. The results show that the model can effectively predict the effluent concentration, saturation adsorption time, and resin loading of each ion. Higher temperatures shorten resin bed life, and lower flow rates and smaller resin particle diameters reduce the initial outflow of each ion and extend saturation adsorption times.