ENSI has reviewed the waste management programme submitted by the parties obliged to carry out waste management at the end of 2021. In its assessment report, ENSI concludes that the parties obliged to carry out waste management have fulfilled their legal mandate. ENSI is submitting seven new requests for requirements to the Federal Council for future waste management programmes.
Nuclear energy legislation requires that waste producers submit a waste management programme every five years. This allows new findings to be taken into account, and consideration to be given to the notes and comments derived from the official assessment reports. Following the Federal Council’s decision on the 2016 Waste Management Programme, the National Cooperative for the Disposal of Radioactive Waste, Nagra, submitted a research, development and demonstration plan (RD&D plan) together with the waste management programme on behalf of those responsible for waste disposal.
Review of the waste management programme
On the basis of its examination, the Swiss Federal Nuclear Safety Inspectorate (ENSI) concludes that Nagra has fulfilled the legal mandate pursuant to Art. 32 Nuclear Energy Act (NEA) and Art. 52 Nuclear Energy Ordinance (NEO) – in relation to those aspects examined by ENSI.
As part of the audit, ENSI assessed all Federal Council requirements for the 2016 Waste Management Programme with respect to their fulfilment. In its assessment report and based on the documents inspected, ENSI recommends further requests for requirements for future disposal programmes. Specific information on individual aspects of the waste management programme and RD&D plan, the safety relevance of which is of secondary importance and which is dealt with within the framework of ongoing oversight, is listed in a separate document (Notes from the assessment of the waste management programme and the RD&D plan 2021).
Realisation of deep geological repositories
ENSI considers the systems of defence-in-depth, passive technical and natural barriers envisaged by Nagra in the disposal concepts for each disposal type to be suitable for ensuring the legally required permanent protection of people and the environment from the ionising radiation of radioactive waste. The principle that both the technical and geological barriers contribute significantly to the barrier effect of the overall system corresponds to official requirements (ENSI-G03). In the waste management programme, Nagra also shows how the repository design is to be optimised in the future approval steps (design and operating approval/licensing).
Based on its review and assessment, ENSI concludes that the waste producers have correctly taken into account the legal and regulatory requirements in the proposed plan for the realisation of deep geological repositories. The implementation plan correctly and transparently maps the successive nuclear licensing procedures, including the site selection procedure. Some aspects are subject to requirements that will continue to apply in the future. New requests for requirements have been formulated in respect of other aspects.
Review of research and development needs
In the current RD&D plan, Nagra explains in detail the planned research and development activities for the next five to ten years. Activities for the future beyond this period are described in more general terms.
ENSI examined whether the time-frame estimated by Nagra for the planned RD&D activities is realistic and whether the research objectives have been chosen in a way that is reasonable to enable the on-time construction of the deep geological repository. Should the targets for the milestones not be achieved or not be achieved in full, Nagra states in the RD&D plan that the only consequence will be delays in the approval process. According to Art. 31 NEA a deep geological repository must be provided in good time by the parties obliged to carry out waste management. ENSI therefore recommends that Nagra explains in more detail in the next waste management programme what measures it intends to take to avoid delays or to keep them as small as possible.
ENSI has also examined how the process of identifying and prioritising research needs at Nagra is conducted. With the roadmaps contained in the RD&D plan, Nagra has listed the important open questions and set a timetable for their answers. With the newly-created roadmaps, Nagra has adequately addressed the topic of outstanding issues. From ENSI’s perspective, the roadmaps must be updated in the next waste management programmes.
Requirement request 1
For the general licence application as well as for future updates of the waste management programme, the packaging concept for the waste packaged in repository containers and the packaged waste volume must be adapted to the disposal concepts resulting from Nagra’s location proposal. In addition, the transport concept for the radioactive waste from the packaging plant to the deep geological repository must be explained. When selecting repository containers, other safety-relevant aspects, such as handling, must be taken into account.
Requirement request 2
In the next waste management programme, simulation tools will be used to examine in more detail the transferability of the acquired findings in the pilot facility to the main facility. In addition, the scope and content of the measurements in the pilot facility must be further specified in a step-by-step manner, and the measurement programme must also be expanded as necessary with regard to the provision of information on the short-term and long-term behaviour of the multiple barrier system and the discovery of unexpected developments during the observation phase.
Requirement request 3
An updated data management plan must be submitted as part of each future waste management programme and must specify how data and information obtained as part of the Sectoral Plan, and collected and processed in the subsequent steps of implementing a deep geological repository, is to be handled. The data management plan must specify when, for how long, and in what quality which data and information are actively available, which information is archived in the long term, which technologies are used for this purpose and which resources are required for this purpose.
Requirement request 4
In the next waste management programme, the parallelisation of processes in connection with the handling of the underground geological investigations (UGI) and the preparation of the nuclear construction and operating licences applications must be specified. It is also necessary to show which additional data is required up to the application for the L/ILW repository part, hierarchy level H1, in order to optimally position the repository parts for a combined repository from the safety point of view.
Requirement request 5
The concept for increasing the number of storage spaces for the interim storage of spent fuel and vitrified highly active waste must be further developed for the next waste management programme, taking into account the findings from the current update of the storage space concept.
Requirement request 6
In future disposal programmes, the RD&D plans for each research area must show the progress of the research projects relative to the previous RD&D plan. This applies in particular to cases where an experiment was unsuccessful or aborted.
Requirement request 7
The next waste management programme should outline strategies for linking data, geometric information, and mathematical models for safety verification. The possible role of modern digital concepts, such as “Building Information Modelling” and “Digital Twins” must be explained.