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In the further development of nuclear fusion energy, managing the high heat flux on a divertor target remains a significant issue. To address this, the development of innovative cooling channels capable of efficiently managing high heat loads is essential. Among various cooling techniques, the hypervapotron (HV) method stands out for its exceptional heat transfer capabilities. This study undertakes an in-depth analysis of a novel HV cooling channel, evaluating its heat transfer performance via an electron beam high heat flux testing system. The focus was on subcooled flow boiling, observing that the novel HV channel displayed varied flow patterns with increasing heat flux. Additionally, a comparative investigation was conducted to assess the heat transfer efficiency of this novel HV channel against traditional ITER-like HV channel and smooth channel. The analysis incorporated various system parameters, such as mass flow rate and system pressure, to understand their effects on heat transfer. To effectively predict the heat transfer performance of the novel HV channel, efforts have been made to evaluate existing and develop new heat transfer correlations for the channel. Furthermore, Artificial Neural Networks (ANNs) have also been utilized as a crucial approach in this predictive endeavor. The outcomes of this study hold significant implications for understanding and optimizing the design of cooling channels for divertor target in nuclear fusion reactors.

To study the manufacturing method of the tungsten armored first wall of tokamak devices, the W-316 L steel (W-SS) composite coatings were fabricated on 316 L steel substrates by detonation spraying (DS) as the interlayer of pure tungsten coatings manufactured by atmospheric plasma spraying (APS). The main characteristics and performance under transient heat shocks of the APS W/DS W-SS /substrate-based three-layer coating system were studied and compared with the APS W/substrate-based coating system. The results showed the porosity of the DS W-SS was about 1.9% with most of the pores smaller than 70 nm. In contrast, the porosity of the APS W reached about 8.6% and most of the pores were up to hundreds of nanometers. The bonding strength tests proved that both the adhesions of APS W to DS W-SS and DS W-SS to the substrate were much higher (almost 1.5 times) than the adhesion of APS W to the substrates. The three-layer specimens performed much better than the APS W/substrate specimens during the transient heat shock tests as expected. Besides, a special microstructure variation occurred on the three-layer specimens before its damage under the tests which was considered helpful to prolong its life-span under high heat flux. In a conclusion, the DS W-SS interlayer improved the service performance of the APS W/substrate-based coating significantly and demonstrates its potential for application in current tokamak experimental devices.

Summary: Replacement of today’s established chemical production processes by “green” sustainable alternatives has become a scientific priority. The oxidative conversion of 5-hydroxymethylfurfural (5-HMF) to the biopolymer component 2.5-furandicarboxylic acid paired with green electrolytic hydrogen production is a promising emerging green process. Here, we present a family of active selective and stable interlayer anion-tuned NiX (X = Fe, Mn, Co, V) bimetallic-layered, double-hydroxide catalysts for the selective oxidation of 5-HMF to 2.5-furandicarboxylic acid in a zero-gap MEA-type electrolyzer. We report that tuning the structural interlayer distance of the catalyst by anion exchange gives rise to previously unachieved catalytic performance for the anodic production of the biopolymer building block. Operando differential electrochemical mass spectrometry analysis reveals the electrode window for the perfectly selective HMF conversion. The role of the catalyst dopants, their real surface areas, the stability of the catalytic interface, and aspects of its favorable techno-economics are discussed.

The tungsten divertor of the Experimental Advanced Superconducting Tokamak (EAST) device operates at varying temperatures and strong electromagnetic fields during plasma operation. In order to monitor the thermomechanical and electromagnetic responses of the structural components, a strain sensor system has been proposed to be applied in the EAST device. To develop this technology, two initial experiments on the thermal strain measurement of a tungsten divertor module of the EAST have been carried out using electrical strain gages and optical strain sensors. However, some engineering issues were exposed during the experiments. Under this condition, all these issues are summarized and discussed this time. Moreover, a comparison between the two techniques has been made when applied in the tungsten divertor. To make them more suitable for the application in the tungsten divertor of the EAST, several activities including a thermomechanical simulation, the welding technologies for the sensors’ installation and a thermal stability test on the optical strain sensors were conducted. Based on these progresses, it is expected that the strain monitoring system will be established in the EAST device in the near future. Keywords: Tungsten divertor, Strain monitoring, Electrical strain gage, Fiber Bragg Grating, EAST