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Nuclear graphite in high-temperature gas-cooled reactors (HTGRs) acts as a moderator, a structural material, as well as an accommodation for fission products (FPs). Given the release of FPs under normal and accident conditions, the diffusion of FPs in nuclear graphite should be elucidated for the estimation of source term and reactor safety. However, the existing experimental data of diffusion are enriched in data of the nuclear graphite types (i.e., H451 and A3), that may not apply to next-generation nuclear graphite. The proposed diffusion theory and experimental systems are conducive to developinging a novel experimental method for the more accurate collection of the diffusion data and an insight into FPs diffusion in graphite. For this reason, this paper reviews the information regarding the diffusion of metallic FPs (e.g., Cs, Sr and Ag) in nuclear graphite. The diffusion theory adopted to calculate the diffusion coefficient is summarized. Emphasis is placed on the measurements for determination the diffusion coefficient and the discussion of detection limits, accuracy and experimental methods. Given the diffusion coefficient data, the variables of diffusion are addressed. The mentioned results lay a basis for gaining insights into the diffusion theory and can be exploited by employing with a valid measurement method to determine the diffusion coefficients of FPs in various nuclear graphite materials under a particular range of conditions.

In High-Temperature Gas-cooled Reactor (HTGR)s, coated fuel particles are dispersed in a graphite matrix, which forms both compact and spherical fuel elements. As for the post irradiation examination (PIE) of HTGR irradiated fuels, the electrochemical deconsolidation method in which graphite matrix is disintegrated into graphite powder is one of the feasible processing methods. The graphite matrix is composed of natural graphite, artificial graphite and glassy carbon from carbonized resin, which have different effects on electrochemical deconsolidation. In this work, synthesized graphite matrix specimens were produced by intentionally varying the resin binder content in the graphite matrix raw materials from 5% to 50%, in order to investigate the electrochemical deconsolidation mechanism of graphite matrix in HTGR fuel elements. The results showed that increasing the glassy carbon content increased the degree of chemical oxidation, with more pronounced production of graphite oxide. The driving force for graphite matrix deconsolidation is proposed to be a synergetic effect of the expansion stress around closed- and through-hole microstructure originating from oxidatively destroyed graphite layers. This work will not only help to more thoroughly understand the electrochemical deconsolidation procedure of HTGR fuels, but also contribute to the development of a feasible method to manage radioactive graphite waste.

Saturation magnetization and ferromagnetic resonance linewidth are important parameters for microwave devices, such as circulator/isolator. Conventional sintering of ferrite ceramics is prevalently performed to promote the densification. Here, we present a new sintering approach for obtaining uniform and dense NiCuZn ferrite ceramics with enhanced gyromagnetic properties at low temperatures. The NiZn-series ferrites (Ni0.2Cu0.2Zn0.6Fe2O3 – 1.0 wt% Bi2O3+0.5 wt% MnO2) was synthesized by solid reaction routes with new sintering approaches. The results indicate that a one-transient-step sintering process (OTSP) can significantly improve the gyromagnetic properties at low sintering temperatures by suppressing the anomalous grain growth, such as higher saturation magnetization (4πMs = ∼3904 Gauss) and lower ferromagnetic resonance linewidth (ΔH = ∼170 Oe). Therefore, such a methodology is quite significant due to it provides a referential experience for effective sintering route that can enable broad practical applications, such as other ferrite ceramics.

For more efficient and accurate determination of airborne tritium in the environment, the procedure optimization, performance test and uncertainty analysis of a commercially available low-background liquid scintillation counting (LSC) system with 100-ml counting vials were studied in this work. The results showed that 50 ml water sample mixed with 50 ml scintillation cocktail (Ultima Gold uLLT, PE) could achieve the optimal counting condition after a dark adaption time longer than 1440 min. The minimum detectable activity (MDA) of the 100-ml vial system was estimated to be 0.18 Bq·L−1 in a continuous counting time of 3600 min, which was approximately 3.5 times lower than that of 20-ml vial system, and its determination uncertainty was also generally lower provided the collected samples was more than 15 ml. It indicates that the LSC system with 100-ml counting vials is preferable for environmental tritium determination. However, for more accurate determination, the electrolytic enrichment is still needed for the sample with the specific activity lower than 0.4 Bq·L−1. On the other hand, considering the cost and potential environmental impact of present available cocktails, the system with 20-ml vials is recommended for determining the sample with the specific activity higher than 2 Bq·L−1.

Nonalcoholic fatty liver disease, a type of metabolic syndrome, continues to rise globally. Currently, there is no approved drug for its treatment. Improving lifestyle and exercise can alleviate symptoms, but patients’ compliance is poor. More and more studies have shown the potential of Polygoni Multiflori Radix (PMR) in the treatment of NAFLD and metabolic syndrome. Therefore, this paper reviews the pharmacological effects of PMR and its main chemical components (tetrahydroxystilbene glucoside, emodin, and resveratrol) on NAFLD. PMR can inhibit the production of fatty acids and promote the decomposition of triglycerides, reduce inflammation, and inhibit the occurrence of liver fibrosis. At the same time, it maintains an oxidation equilibrium status in the body, to achieve the therapeutic purpose of NAFLD and metabolic syndrome. Although more standardized studies and clinical trials are needed to confirm its efficacy, PMR may be a potential drug for the treatment of NAFLD and its complications. However, the occurrence of adverse reactions of PMR has affected its extensive clinical application. Therefore, it is necessary to further study its toxicity mechanism, enhance efficacy and control toxicity, and even reduce toxicity, which will contribute to the safe clinical use of PMR.

An efficient thermal management system is essential to maintain its good performance of a power battery pack. Evaluating the impacts of influential factors on the system cooling performance helps guide the design of the battery thermal management system. In the present work, a battery thermal management system based on heat pipes combined with a liquid-cooling plate is proposed. Orthogonal design and fuzzy grey relational analysis are employed as evaluating methods, and numerical simulations are carried out to investigate the influence of four structure parameters of the aluminum sheet (the height, the thickness, the covering angle to battery, and the covering angle to heat pipe) on the temperature distribution of the battery pack. Results show that, in order to keep a good operating temperature range of the battery, the values of the height, the thickness, the covering angle to battery and the covering angle to heat pipe of the aluminum sheet are suggested to be above 50 mm, 2 mm, 75° and 60°, respectively. The covering angle of aluminum sheet to battery has the most influential impact on the system cooling performance, and the covering angle to heat pipe has the slightest influence. The optimal value of the maximum temperature is 37.58 °C and the temperature difference is 3.67 °C.

Comparison is an important role in the quality control and quality assurance for any measuring system. Due to the future legal regulations regarding radon levels in the air, maintaining the system quality and harmonization of results as well as validation of radon and thoron measuring systems is important. The aim of this work is to validate the degrees of equivalence and measurement precisions of the existing five radon and four thoron measuring systems located in four Asian countries (China, India, Japan and Thailand) through comparison experiment. In this project, comparison experiment was performed in order to derive the ratio between assigned value obtained from one transfer measurement device for radon and one transfer measurement device for thoron belongs to National Institutes for Quantum and Radiological Science and Technology and participants&rsquo, value from their measuring instrument. As a result, the ratio value associated with measurement uncertainty was derived for each activity concentration. Finally, measurement bias and degrees of equivalence between the assigned values and values of measurement quantity from participants&rsquo, measuring instruments were statistically analysed and presented.

A ratiometric fluorescence detection method for trace amount of uranyl ion (UO 2 2+ ) was developed in this study, based on aggregation induced emission enhancement (AIEE) characteristics of 3-hydroxyflavone salicylaldehyde azine (HFSA) and luminescent signal of UO 2 2+ -HFSA complex in soluble state. The fluorescent ratio ( I 457 / I 534 ) was linearly related to the concentration of UO 2 2+ in the range of 0.5–20 ppb (part per billion). Analytical data showed that a detection limit of 0.5 ppb was achieved with the relative standard deviation (R.S.D.) 1.3% ( n =5). The proposed method could also be utilized for imaging UO 2 2+ in living cells by ratiometric fluorescence changes.