• Automation is based on modular finite state machines for process and safety control. • Interlock groups ensure safe gas handling during B₂D₆ plasma operation. • Automation significantly reduces the workload of the boronization operation team. • Process-critical events are synchronized via global control byte. High performance operation of magnetic confinement fusion reactors requires conditioning of the plasma-facing components by boronization [ 1] . This boron hydride layers traps residual oxygen in the vacuum vessel, thereby reducing radiation losses and, especially in metal components, mitigating sputtering by oxygen ions. Technically, at ASDEX Upgrade this coating is formed by a glow discharge process, using 10 % deuterated diborane (B 2 D 6 ) in helium as carrier gas (hereafter referred to as the “B₂D₆/He mix”). In this publication, we report on the complex software architecture, which was generally realized in the form of finite state machines (FSM). These state machines contain the entire process control of the boronization process, incorporating all the safety interlocks stored in a locking matrix. With this new procedure, the boronization can be carried out within 6 h on a normal working day, without the need to evacuate the office buildings adjacent to the experimental hall.

In the last years, an intense research activity has been carried out within the framework of the EUROfusion Consortium to optimize the layout of the EU-DEMO Breeding Blanket (BB). Two main concepts are currently under investigation: the Helium-Cooled Pebble Bed and the Water-Cooled Lead-Lithium, that is the option object of this work. This layout relies on pressurized water as coolant, liquid metal (i.e., lead-lithium) as breeder, neutron multiplier and tritium carrier, and reduced-activation ferritic/martensitic steel as structural material. In addition, a thin tungsten armor is used to protect the First Wall component. The overall BB is constituted by sixteen toroidal sectors. Each sector is composed by inboard (two) and outboard (three) segments, considering their radial position with respect to the plasma chamber. At its time, the segments consist in a stack of vertically-piled breeding cells, that are the system elementary units. Their layout differs according to the poloidal position and the segment they belong. To obtain an affordable BB design, one of the key issues is assessing its thermal-hydraulic performances during operational and accidental conditions. For this, an analysis of the component transient behavior is needed to improve and refine the project. To achieve this goal, during the last year, the Nuclear Engineering Research Group of Sapienza University of Rome, in collaboration with ENEA, has developed a detailed model of the DEMO WCLL BB sector, including both the inboard and outboard segments. The rationale has been dividing the overall stack of cells belonging to each segment in poloidal sections. The number of these sections has been the object of a sensitivity study. The preliminary objective of this work is to have a dedicated BB sector model to evaluate its thermal-hydraulic performances at a system level during the DEMO normal operations, considering the pulsed plasma regime and the spatial distributions of the various loads insisting on this component. In addition, the developed input deck allowed to have insights into the BB behavior during accidental conditions, demonstrating the capability of the current design to effectively withstand such scenarios without exceeding safety margins. The level of detail adopted to prepare the BB model enabled to preliminary exclude the occurrence of local damaging phenomena, such as thermal crisis.

• Water formation reaction on LiAlO 2 was observed above 450 °C. • T diffused from inner LiAlO 2 grain is considered to occur water formation reaction. • Redox reaction rate of H 2 O on Zr increased above 700 °C. • T release peak from the 700 °C-preheated LiAlO 2 with Zr was observed at 200, 800 °C. • Mass transfer resistance of Zr oxide layer is considered to deteriorate above 700 °C. Tritium (T) production using a high-temperature gas-cooled reactor (HTGR) has been proposed to arrange initial T inventory for nuclear fusion reactors. For the establishment of this method, the behavior of T in a Li-loading rod (Li-rod), which contains LiAlO 2 and zirconium (Zr), needs to be understood. In this study, a powdered LiAlO 2 sample was heated in H 2 containing Ar gas flow to observe water formation reaction. Then, a powdered Zr sample was heated in humid Ar gas flow to investigate the temperature dependence of H 2 O reduction rate on the Zr. Finally, a Zr-mixed LiAlO 2 sample, which had been neutron-irradiated in the Kyoto University Research Reactor (KUR), was preheated at 700 °C in a sealed quartz tube, and then heated in Ar gas flow to observe the release behavior of T from the sample. Released gaseous T (HT, T 2 ) and tritiated water vapor (HTO, T 2 O) were separately collected using a pair of bubblers installed upstream and downstream of a copper oxide (CuO) bed, and the tritium concentration in each bubbler was measured using a liquid scintillation counter. Based on the results, it is suggested that LiAlO 2 should be in advance heated in reduction atmosphere to remove adsorbed water and unstable oxygen to suppress the release of T in chemical form of HTO, and Li-rod should be operated at higher temperatures over 700 °C to decrease the mass transfer resistance by an oxide layer on Zr.