[en] The effect of mid span mixing grid (MSMG) on the EPR core thermal- hydraulic parameters and minimum DNBR was analyzed by employing FLICA Ⅲ-F sub- channel code. The results show that DNBR margin of EPR core can be improved respectively about 24% and 28% for normal condition with cosine and AO equal to + 9% power distributions by adding 4 MSMGs on AFA 3GLE fuel assembly, while the pressure drop in EPR core increases about 10.1%. (authors)

[en] Objective: To establish a new, rapid, and effective method to identify ¹³N-NH₃ and analyze its radiochemical purity. Methods: The chromatographic method of high performance liquid chromatography-ultraviolet(HPLC-UV)-flow-count was performed using a C18 column with mobile phase of acetonitrile and 5 mmol/L sodium 1-octanesulfonate solution(V/V = 1/3)at a flow rate of 0.5 ml/min and a wavelength of 210 nm. 15% ¹³N-NH₃ and 0.1 mg/ml NaNO₃ were detected separately, and their retention times were compared and identified. Results: The UV retention times of NH₃ and NaNO₃ were 2.3 and 1.4 min, respectively, and the retention times of ¹³N-NH₃ and ¹³N-NO_x^- were 5.8 and 3.1 min, respectively. The established separation method using HPLC-UV-flow-count showed good efficiency. Conclusion: HPLC-UV-flow-count is a simple, valid, and rapid method to identify ¹³N-NH₃ and analyze its radiochemical purity. (authors)

[en] In order to study the pressure drop characteristics of sump strainer after loss of coolant accident, pressure drop of filter cartridge at full load is experimentally studied and the flow field of collecting tray of sump strainer is simulated by Fluent. The result found that: pressure drop is lager at the part of cross section change, especially in the sudden shrinkage or expansion of cross section; By addition of pressure drop caused by cartridge and collecting tray, which is obtained from experiment and simulation respectively, the total pressure drop of sump strainer meet the requirement of Safety Injection System. (authors)

[en] A novel closed-form expression for predicting the equivalent electromagnetic parameters of the honeycomb structure is proposed. It is obtained by approximating the correlation terms in the derivation of the strong fluctuation theory with the integral of the spherically symmetric function. Through several simulation examples, the calculation results of the formula are compared with the results of several traditional extraction methods and compared with the existing experimental data. Comparison of the extraction results of the formula with the simulation results and the experimental data shows good agreement, which proves the feasibility of the extraction expression, and this method does not require simulation as a prerequisite and can shorten the time for optimizing the design of the honeycomb absorbing structure. (paper)

[en] Abnormal tension occurs on the main pump snubber tie rod of a nuclear station when it is loaded by bolt stretcher. In order to solve this problem, this paper uses the methods of cause elimination and analytical calculation to diagnoze the fault. It is identified that the main reason for abnormal tension is the short thread length. In view of this problem, the scheme of adjusting the screw thread length is proposed and verified by the finite element method, and the stress analysis of the anchor rod thread also meets the requirements of the code. The handling of this event can guarantee the construction progress on site and avoid great economic loss. (authors)

[en] In this paper, filtering property and pressure drop performances of the in-containment refueling water storage tank (IRWST) sump strainers system were studied. The research work was performed with experimentation and numerical simulation methods, including experimental research on the downstream debris concentration and the pressure drop analysis of the strainers. The results show that the downstream debris concentration is 368 ppm under accidental condition, and the pressure drop of the RIS and HER sump strainers is 3.533 kPa and 3.631 kPa, respectively, which meet the functional requirements of the downstream debris concentration (480 ppm) and system pressure drop (5.6 kPa) of the IRWST sump strainers. (authors)

[en] Background: Positron emission tomography (PET) is in rapidly developing as a powerful imaging technique for diagnosis, efficacy evaluation and prognosis of tumor. In contrast to ¹⁸F-FDG, the amino acid tracers were helpful additional tools for differentiating tumor tissue and inflammation, edematous, necrotic and fibrotic tissue because of their low uptake in those tissues, so that amino acid tracers appear to be more specific than the widely used ¹⁸F-FDG. As a result, a number of attempts have been undertaken for radio-synthesis of amino acid with short half-life nuclide ¹⁸F and ¹¹C. Purpose: The aim is to review and discuss the present knowledge on synthesis methods and preliminary clinic application of labeling amino acid. Methods: The advances on the synthesis methods and preliminary clinic application of labeling amino acid in recent years were introduced and discussed. Results: In recent years, many new ¹⁸F or ¹¹C-labeled amino acids have been developed and their preliminary clinic applications were studied. Conclusion: The review provides an overview of this class of radiolabeled amino acids and highlights the current synthesis status and the key preliminary clinic applications. (authors)

[en] Highlights: • The optical eigenmode in far-field thermal ghost imaging system is proposed. • The equal-weighted eigenmode sampling shows the ghost image with high-visibility. • The requirement for discrete sources replacing a continuous source is discussed. The eigenmode sampling theorem of the single-frequency chaotic light in far-field ghost imaging (GI) scheme is theoretically studied. In the GI scheme, the chaotic source not only plays the role of illumination, but also acts as a pupil filter, determining the unequal-weighted eigenmode sampling. Here, we have theoretically and experimentally studied a filtering tool to achieve equal-weighted eigenmode sampling, thereby producing ghost images of higher visibility than traditional methods. The presented work can be considered as a step towards meeting the visibility requirement of multiphoton imaging system with classical light.

[en] We theoretically investigate a band-stop filter based on a metal-insulator-metal waveguide with a single-sided multiple-teeth-shaped structure. Three-teeth-shaped structure is used to realize the U-shaped transmission spectrum. The central wavelength of the filter can be adjusted by the depth of the teeth, and the bandwidth can be slightly modified by the spacing between the teeth-shaped cavities. Moreover, by changing the spacing of the teeth-shaped cavities, we found the suitable data to achieve the best U-shape transmission spectrum. The criterion for judging the U-shaped transmission spectrum is the comparison of the slopes of U-shape’s both sides. The unilateral-multiple-teeth-shaped filter based on double Fano line-shapes has small band-stop width less than 200 nm and can be used to design narrow band-stop filter. (paper)

[en] In this study, degradation of fracture toughness due to thermal aging was considered in the probabilistic fracture mechanics analysis of nuclear pressure pipes. A predicting program for pipe break probability based on thermal aging embrittlement was developed. On the basis of experimental data of a pipe material, evolution of the fracture toughness at 280℃ and 330℃ were estimated using the Argonne National Laboratory (ANL) procedure. Failure probability of a pipe with a circumferential inner surface crack was calculated in two cases: consideration and without consideration of thermal aging. The result show that failure probability is higher when thermal aging embrittlement was considered. Also, cumulative failure probability at 280℃ and 330℃ were compared. The results indicate that pipe will suffer more serious thermal aging and have higher failure probability when operating at a higher temperature. (authors)