分类： 物理学 >> 核物理学 提交时间： 2024-03-07
摘要： Predicting the transition-temperature shift (TTS) induced by neutron irradiation in reactor pressure-vessel (RPV) steels is important for the evaluation and extension of nuclear power-plant lifetimes. Current prediction models may fail to properly describe the embrittlement trend curves of Chinese domestic RPV steels with relatively low Cu content. Based on the screened surveillancedata of Chinese domestic and similar international RPV steels, we have developed a new fluence-dependent model for predicting the irradiation-embrittlement trend. The fast neutron fluence (E> 1 MeV) exhibited the highest correlation coefficient with the measured TTS data; thus, it is a crucial parameter in the prediction model. The chemical composition has little relevance to the TTSresidual calculated by the fluence-dependent model. The results show that the newly developed model with a simple power-law functional form of the neutron fluence is suitable for predicting the irradiation-embrittlement trend of Chinese domestic RPVs, regardless of the effect of the chemical composition.
分类： 物理学 >> 核物理学 提交时间： 2023-12-19
摘要： The microscopic global nucleonnucleus optical model potential (OMP) proposed by Whitehead, Lim, and Holt, the WLH potential 1 , which was constructed in the framework of many-body perturbation theory with state-of-the-art nuclear interactions from chiral effective field theory (EFT), was tested with (p, d) transfer re#2;actions calculated using adiabatic wave approximation. The target nuclei included both stable and unstable nuclei and the incident energies reached 200 MeV. The results were compared with experimental data and pre#2;dictions using the phenomenological global optical potential of A. J. Koning and J. P. Delaroche, the KD02 potential. Overall, we found that the microscopic WLH potential described the (p, d) reaction angular distri#2;butions similarly to the phenomenological KD02 potential; however, the former was slightly better than the latter for radioactive targets. On average, the obtained spectroscopic factors (SFs) using both microscopic and phenomenological potentials were similar when the incident energies were below approximately 120 MeV. However, their difference tended to increase at higher incident energies, which was particularly apparent for the doubly magic target nucleus 40Ca.
分类： 物理学 >> 核物理学 提交时间： 2023-06-26
摘要： Neutron computed tomography (NCT) is widely used as a noninvasive measurement technique in nuclear engineering, thermal hydraulics, and cultural heritage. The neutron source intensity of NCT is usually low and the scan time is long, resulting in a projection image containing severe noise. To reduce the scanning time and increase the image reconstruction quality, an effective reconstruction algorithm must be selected. In CT image reconstruction, the reconstruction algorithms used can be divided into three categories: analytical algorithms, iterative algorithms, and deep learning. Because the analytical algorithm requires complete projection data, it is not suitable for reconstruction in harsh environments, such as strong radiation, high temperature, and high pressure. Deep learning requires large amounts of data and complex models, which cannot be easily deployed, as well as has a high computational complexity and poor interpretability. Therefore, this paper proposes the OS-SART-PDTV iterative algorithm, which uses the ordered subset simultaneous algebraic reconstruction technique (OS-SART) algorithm to reconstruct the image and the first-order primal-dual algorithm to solve the total variation (PDTV), for sparse-view NCT three-dimensional reconstruction. The novel algorithm was compared with other algorithms (FBP, OS-SART-TV, OS-SART-AwTV, and OS-SART-FGPTV) by simulating the experimental data and actual neutron projection experiments. The reconstruction results demonstrate that the proposed algorithm outperforms the FBP, OS-SART-TV, OS-SART-AwTV, and OS-SART-FGPTV algorithms in terms of preserving edge structure, denoising, and suppressing artifacts.
分类： 化学 >> 核化学 提交时间： 2023-05-31
摘要： The rapid development of advanced techniques for selective and efficient U(VI) extraction from aqueous solutions is essential for addressing U(VI) environmental pollution and energy issues. Here, we share recent progress in U(VI) extraction from aqueous solutions, especially the most frequently applied techniques such as adsorption, catalysis (photocatalysis, piezocatalysis, and electrocatalysis), chemical deposition, and reduction by zero-valent metal particles. We attempt toelucidate the strategies and various mechanisms that contribute to the enhancement of selective U(VI) extraction. At the end of our review, we highlight the outlook, challenges, and prospects for the development of this field.
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