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The International Energy Agency (IEA) has been promoting the IEA Environment, Safety and Economic Aspects of Fusion Power program for many years. Among the tasks of this program, one task in particular deals with radioactive waste management in order to analyze the issue of the final destination of fusion activated and tritiated materials after their use in a fusion power reactor. A collaborative study on these aspects has been carried out in recent years. An optimized waste management strategy is proposed, with the goals of avoiding underground disposal as much as possible, maximizing recycling of activated materials within the nuclear industry, and/or clearance and release to commercial markets if materials contain only slight traces of radioactivity. Some technological problems and recent research advances in this field are summarized.

The 2nd International Workshop on Environmental, Safety and Economic Aspects of Fusion Power (ESEFP) was held on 23 September 2017 in Kyoto, Japan. The workshop was initiated by the International Energy Agency Technology Collaboration Program on ESEFP. The workshop was well attended with approximately forty participants representing fifteen institutions in eight countries. The presentations covered safety issues and environmental impacts, availability improvement and risk control and socio-economic aspects of fusion power. Quantitative safety assessment of fusion reactors was discussed in depth with the consensus output presented as a plenary presentation at the 13th International Symposium on Fusion Nuclear Technology (ISFNT-13). The next workshop is planned to be held in conjunction with the ISFNT-14 in 2019.

To assist in the development of nuclear fusion as a viable commercial power source, preparation is underway for the fusion demonstration reactor (DEMO), which will build on the work of ITER, the international experimental fusion reactor. Like other advanced nuclear energy systems, DEMO must satisfy several goals including a high level of public and worker safety, low environmental impact, high reactor availability, a closed fuel cycle and the potential to be economically competitive. Yet there are still large scientific and technological safety gaps between the on-going ITER project and DEMO that will need to be addressed. Here we review international fusion safety research and development relevant to DEMO, following the lessons learned so far from ITER. We identify the main scientific and technological safety gaps, drawing on knowledge from the development of fission energy, in particular Generation IV (Gen-IV) fission reactors. From this survey, we discuss the corresponding implications for the design and operation of DEMO.

Remote replacement of the ITER divertor will be required several times during the life of ITER-FEAT because of failure, erosion of the armour or in order to install alternative divertor geometries. An R&D project was conceived during the ITER EDA to demonstrate the feasibility and the reliability of the divertor remote maintenance operations. Two test platforms have been set up and are being used to evaluate equipment and procedures, maintenance and refurbishment times, and rescue scenarios. Following a short description of the test facilities set up at ENEA, Brasimone, Italy, the paper reports on the results from the two platforms, which confirm the overall feasibility of the proposed maintenance and refurbishment schemes. The paper also describes the programme of work currently underway which is aimed at verifying the design changes made necessary by the move from the 1998 ITER design to the more compact ITER-FEAT design, and by design short-comings highlighted during the operation of the platforms.

The divertor of ITER fusion reactor consists of cassettes, which are designed to be replaced and maintenanced regularly. For maintenance, the cassettes are transported into a hot cell. In the hot cell, maintenance operations include cleaning and careful measuring of the cassette and replacing of three Plasma Facing Components. Due to complex and critical nature of the divertor maintenance, the PFC replacement is tested and practised in Divertor Refurbishment Platform (DRP) in ENEA Research Centre in Brasimone, Italy. Contribution of TUT/IHA (association TEKES) has been to design and manufacture tooling for the PFC's replacement. Two sets of tool prototypes has been designed, manufactured and delivered to DRP. Each set of tools were designated for replacement operation of the outer vertical PFC of the cassette, different attachment option. During the tool design the requirements set by the attachment method, handling equipment and remote control limitations were taken into consideration. The designed tools and operation sequences were first tested in 3D virtual model in computer made with Envision software before manufacturing them. In the paper, the tool prototypes, their design considerations and used design methods are presented.

The divertor assembly for the ITER-FEAT fusion reactor consists of 54 rail mounted cassettes located in the bottom region of the vacuum vessel. These cassettes comprise a stainless steel body, designed for the full lifetime of ITER, onto which are mounted 3 sacrificial Plasma Facing Components (PFC's). The latter are designed to be replaced a number of times during the lifetime of the machine to allow for component failure, erosion of the armour or in order to implement alternative divertor geometries. To demonstrate the feasibility of the refurbishment process a test facility know as the Divertor Refurbishment Platform (DRP) has been established at the ENEA Research Centre in Brasimone, Italy, as part of the large ITER R&D project L7. Within this facility a number of PFC assembly, disassembly and handling operations have been carried out on a full size mock-up of a divertor cassette to optimise hot cell equipment design and Remote Handling maintenance methods. Following a short description of the DRP facility, equipment and methods, this paper reports the results and draws conclusions from the extensive testing of PFC-to-cassette attachment schemes in order to assess their in-service performance and suitability to remote maintenance operations. Finally, outstanding issues regarding the cassette refurbishment approach are highlighted and future activities discussed.