Report of the US ITER Research Program Research Needs Workshop

The US ITER Research Program Basic Research Needs Workshop, held over the course of several months in 2022 with over 400 participants, sought to identify steps to be taken to both maximize the return of the US investment in ITER construction and operation and to ensure US research priorities on ITER strengthen the domestic program aimed at the development of a fusion pilot plant (FPP)

Diagnostic systems in DEMO: engineering design issues

The diagnostic systems of DEMO that are mounted on or near the torus, whether intended for the monitoring and control functions of the engineering aspects or the physics behaviour of the machine, will have to be designed to suit the hostile nuclear environment. This will be necessary not just for their survival and correct functioning but also to satisfy the pertinent regulatory bodies, especially where any of them relate to machine protection or the prevention or mitigation of accidents foreseen in the safety case. This paper aims to indicate the more important of the reactor design considerations that are likely to apply to diagnostics for DEMO, drawn from experience on JET, the provisions in hand for ITER and modelling results for the wall erosion and neutron damage effects in DEMO.Comment: 8 page

Computer-Aided Bilateral Teleoperation of Manipulators

Haptic bilateral teleoperation is often a challenging and mentally demanding job for the operators of robot control systems. It is especially difficult in cases such as the remote maintenance of the ITER divertor region. The difficulty of the ITER divertor maintenance hails from a multitude of reasons: the residual radiation level of the ITER reactor during a shutdown is too high for any human access, the maintenance tunnels of the divertor are confined, the operators have to operate heavy loads in delicate tasks, and only a limited number of radiation tolerant cameras are available for providing video feedback. In addition, most of the maintenance work cannot be automated because of the dynamic nature and complexity of the tasks. Haptic shared control systems can be used for reducing the amount of mental and physical workload perceived by the operators of remote maintenance systems. To reduce the workload, a haptic shared control system assists the operators by generating virtual forces based on the virtual models of the teleoperation environment and sensor data from the slave manipulator. The generated assistance forces are laid over the force feedback signals from the teleoperation environment. The assisting forces can e.g. guide the operators along optimal paths and prevent collisions in the teleoperation environment. In addition to the reduction of the operator workload, teleoperation tasks also become faster and safer with haptic shared control. This thesis investigates the implementation techniques and theory of haptic bilateral teleoperation and shared control systems. Based on the theoretical analysis, an experimental haptic shared control system, called the Computer Assisted Teleoperation (CAT) was developed. The intention of CAT is to assist the remote handling (RH) system operators of the Divertor Test Platform 2 (DTP2) in ITER remote maintenance research. The effectiveness of CAT is evaluated in a teleoperation experiment performed with a 6 DOF Water Hydraulic MANipulator (WHMAN) developed for the ITER divertor maintenance. The results of the experiment gives directive indication that the CAT system improves the execution times of a bilateral teleoperation task and simultaneously reduces the workload perceived by the operators of the system

Design of a distributed data acquisition system for the ITER’s neutral beam

The International Thermonuclear Experimental Reactor (ITER) is a groundbreaking interna- tional collaboration aimed at developing fusion energy as a clean, safe, and virtually limitless source of power that brings together scientists, engineers, and experts from 35 countries to con- struct and operate the world’s largest experimental fusion reactor. Through the fusion of hy- drogen isotopes, ITER seeks to replicate the process that powers the sun and stars, harnessing the immense energy released to generate electricity. With its ambitious goals and cutting-edge technology, ITER represents a significant milestone in the pursuit of sustainable and abundant energy for the future. As part of the ITER project, the development of several systems of plasma heating is needed to achieve fusion conditions in order to reach plasma ignition. One of such heating systems is the Heating Neutral Beam (HNB), which is designed to inject a energetic beam of neutral atoms into the plasma and heat the fusion plasma by coulomb collisions of such with the plasma. This system requires of several components such as power supplies, cryopumps and cooling components working together in order to achieve a controlled and safe operation of the HNB. It also needs to work coordinated with the experimental control with high availability. The neutral beam control system is, therefore, responsible for the correct and safe operation of the two HNB units installed at ITER. The project presents an overview of the instrumentation and control system currently being developed for the Neutral Beam units and presents the development and design of a remote distributed data acquisition system prototype for the Neutral Beam instrumentation and control system. The performance of the prototype will be measured and evaluated to determine if such solution is fit for ITER requirements and can therefore be implemented into the Neutral Beam control system and other control systems within the reactor components. This project was developed under the Traineeship program by the European Joint Undertaking for ITER and the Development of Fusion Energy, Fusion For Energy (F4E). This report presents the work the author performed during such contract and under the guidance of the program’s supervisor

Conceptual design of the liquid metal laboratory of the TECHNOFUSION facility

The application of liquid metal technology in fusion devices requires R&D related to many phenomena: interaction between liquid metals and structural material as corrosion, erosion and passivation techniques; magneto-hydrodynamics; free surface fluid-dynamics and any other physical aspect that will be needed for their safe reliable operation. In particular, there is a significant shortage of experimental facilities dedicated to the development of the lithium technology. In the framework of the TECHNOFUSION project, an experimental laboratory devoted to the lithium technology development is proposed, in order to shed some light in the path to IFMIF and the design of chamber's first wall and divertors. The conceptual design foresee a development in two stages, the first one consisting on a material testing loop. The second stage proposes the construction of a mock-up of the IFMIF target that will allow to assess the behaviour of a free-surface lithium target under vacuum conditions. In this paper, such conceptual design is addressed

Challenges in materials research for sustainable nuclear energy

Global energy demand is expected to increase steeply, creating an urgent need to evolve a judicious global energy policy, exploiting the potential of all available energy resources, including nuclear energy. With increasing awareness of environmental issues, nuclear energy is expected to play an important role on the energy scenario in the coming decades. The immediate thrust in the science and technology of nuclear materials is to realize a robust reactor technology with associated fuel cycle and ensure the cost competitiveness of nuclear power and to extend the service life of reactors to 100 years. Accordingly, the present-generation materials need to be modified to meet the demands of prolonged exposure to irradiation and extended service life for the reactor. Emerging nuclear systems incorporate features to ensure environmental friendliness, effective waste management, enhanced safety, and proliferation resistance and require development of high-temperature materials and the associated technologies. Fusion, on a longer horizon of about fve decades, also requires the development of a new spectrum of materials. The development of next-generation materials technology is expected to occur in short times and is likely to be further accelerated by strong international collaborations

Conceptual Design of a Fast-Ignition Laser Fusion Reactor FALCON-D

A new conceptual design of the laser fusion power plant FALCON-D (Fast ignition Advanced Laser fusion reactor CONcept with a Dry wall chamber) has been proposed. The fast ignition method can achieve the sufficient fusion gain for a commercial operation (~100) with about 10 times smaller fusion yield than the conventional central ignition method. FALCON-D makes full use of this property and aims at designing with a compact dry wall chamber (5~6m radius). 1-D/2-D hydrodynamic simulations showed the possibility of the sufficient gain achievement with a 40 MJ target yield. The design feasibility of the compact dry wall chamber and solid breeder blanket system was shown through the thermomecanical analysis of the dry wall and neutronics analysis of the blanket system. A moderate electric output (~400MWe) can be achieved with a high repetition (30Hz) laser. This dry wall concept not only reduces some difficulties accompanied with a liquid wall but also enables a simple cask maintenance method for the replacement of the blanket system, which can shorten the maintenance time. The basic idea of the maintenance method for the final optics system has also been proposed. Some critical R&D issues required for this design are also discussed