A position paper by the UK Committee on Radioactive Waste Management (CoRWM) looks at the development of small modular reactors (SMRs) and advanced modular reactors (AMRs) and the implications for management of high-level wastes (HLW) and used fuel. Noting the growing interest in SMRs and AMRs, the 42-page paper says: “The management of spent fuel and radioactive waste from these new reactors must also be considered when selecting technologies for investment, further development, construction and operation.”
The paper provides recommendations to the UK Government, Great British Nuclear (GBN) and Nuclear Waste Services (NWS - part pf the Nuclear Decommissioning Authority) and regulators with respect to SMR and AMR deployment.
CoRWM notes that the management of used fuel and radwaste from these new reactors must be considered when selecting technologies for investment, further development, construction and operation. “This must involve addressing the uncertainties about such management at an early stage, to avoid costly mistakes which have been made in the past, by designing reactors without sufficient consideration of how spent fuel and wastes would be managed, and also to provide financial certainty for investors regarding lifetime costs of operation and decommissioning.”
However, the Committee noted that the Rolls-Royce SMR Generic Design Assessment (GDA) submission documents include “a discussion on optimisation through application of Best Available Techniques (BAT) to prevent the generation, and where this is not possible, minimise the volume and activity of wastes produced, disposed, and discharged and to minimise the consequent impact of such wastes on members of the public and the environment, which we commend”.
The report concluded that the management of used fuel and radwaste from these new reactors “must be considered when selecting technologies for investment, government support, further development, construction and operation”. This must involve addressing “the uncertainties about such management at an early stage, to avoid the costly mistakes which have been made in the past, and also to provide financial certainty for investors regarding lifetime costs of operation and decommissioning”.
It is essential to know:
- the nature and composition of the waste and, in particular, of the used fuel;
- its likely heat generation and activity levels;
- how it will be packaged and its volume; and
- when it is likely to arise.
CoRWM says different types of reactor, ranging from those that are very similar to current pressurised water reactors (PWRs) to those using exotic fuels about which little is known, will present “highly variable levels of confidence” as to how the used fuel and waste will be managed and ultimately disposed. Even reactor types that are well known “will have important operating variables to be clarified”. How the reactor is operated and refuelled “will have potentially significant implications for interim radioactive waste management and disposal”.
It is not necessarily the case that all types of used fuel and radwaste will be suitable for disposal in a geological disposal facility (GDF) without difficult prior treatment processes. Some materials may simply not achieve the necessary state of passive safety required, without substantial processing “and maybe not even then”. There are important questions which may impact the consenting processes for the GDF and also affect the financial provision to be made by developers and investors for decommissioning and transfer to any GDF. Making a GDF suitable for receiving future and indeterminate forms of waste and used fuel “would most likely involve substantial additional cost and complexity”.
Government and GBN should make this clear to manage the expectations of some vendors and provide clarity to potential investors. “We do not advocate saying that specific designs should be ruled out, as this is ultimately a question for the developer and investors, but clear guidance is required.”
NDA and NWS have a vital role in assessing disposability. “Early discussion between developers and NWS is clearly advisable but, with some exceptions such as RR SMR, this appears to be happening only to a very limited degree.” It is for developers, not the NDA/NWS, to fund and undertake the necessary research, which may be extensive. NWS must be consulted about such research and will need to have full access to it in support of its disposability assessment and development of the GDF.
An important issue of timing needs to be addressed between the emergence of the necessary information on used fuel and waste from new types of reactor and the GDF development process. These questions will also impact the design and safety case of the GDF for the purposes of applying for a development consent order and other environment and safety consents.
The report made the following recommendations:
- Clear guidance is needed from government to promoters, regulators and GBN on the need to the cost, safety and environmental issues associated with radioactive waste management at an early stage.
- Government should make clear what degree of certainty will be required regarding the back end of the nuclear fuel cycle – the proposed approach to and associated costs of the used fuel and radwaste management from operation and decommissioning.
- The role of NWS should be emphasised to encourage early engagement in the process. NWS will need the necessary resources for this task if a number of possible technologies are to be considered.
- It is important that developers of new reactors have sufficient management capability and expertise to understand and assess the back-end issues, and to be an intelligent customer where they rely on outside expertise. Where the GDA process is pursued, this should be an important aspect. The required growth in skills to meet these challenges must be addressed.
