Waste issues need consideration in SMR deployment, says CoRWM

14 February 2024

Waste management issues need to have a significantly greater prominence in the process of developing and deploying small modular reactor and advanced modular reactor designs, according to the UK's Committee on Radioactive Waste Management (CoRWM).

The six contenders in the UK SMR contest (Image: Composite of each firm's visuals)

"There is considerable impetus for the development of small modular reactor (SMR) and advanced modular reactor (AMR) designs and their commercial deployment, both for energy security and for environmental reasons, particularly given the historic difficulties of deploying reactors at gigawatt scale," CoRWM notes in a new position paper.

However, it says the issue of managing the used fuel and radioactive waste from these new reactors "appears, with some exceptions ... to have been largely ignored or at least downplayed up to now". It adds that the issue "must be considered when selecting technologies for investment, further development, construction and operation".

The paper says: "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."

CoRWM says 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 could feasibly be packaged and its volume; and when it is likely to arise.

"So far there is little published material from the promoters and developers of new reactor types to demonstrate that they are devoting the necessary level of attention to the waste prospectively arising from SMR/AMRs," it notes.

The position paper provides recommendations to the UK government, Great British Nuclear (GBN), and Nuclear Waste Services and regulators to consider as SMR and AMR deployment is progressed.

"There are many questions to be answered concerning the radioactive waste and spent fuel management aspects of the design and operation of SMRs and AMRs," CoRWM says. "This paper begins the process of raising them, with the caveat that our knowledge of the reactor designs and their fuel requirements is relatively immature compared with large GW reactors."

CoRWM says there are various mechanisms by which these questions could be addressed in the process of obtaining approval for the new reactors. These are principally: the process of justification, which will be mandatory for all new reactor types; Generic Design Assessment which is optional and non-statutory; nuclear site licensing; and environmental permitting.

"The last two stages of control may in some cases come too late in the process to allow for effective optimisation of designs and the selection of materials that reduce waste," CoRWM says. "It remains to be seen how effective these mechanisms will be and whether they will occur sufficiently early in the decision-making process to ensure that radioactive waste management is fully and responsibly addressed."

CoRWM was established in 2003 as a non-statutory advisory committee and is classed as a non-departmental public body. Its purpose is to provide independent advice to the UK government, and the devolved administrations based on scrutiny of the available evidence on the long-term management of radioactive waste, arising from civil and, where relevant, defence nuclear programmes, including storage and disposal.

The UK government has plans to expand nuclear energy capacity to 24 GW by 2050, with a fleet of SMRs a key part of that strategy. Last year, the government and the new GBN arms-length body set up to help deliver that extra capacity began the selection process for which SMR technology to use. In October, EDF, GE Hitachi Nuclear Energy, Holtec, NuScale Power, Rolls Royce SMR and Westinghouse were invited to bid for UK government contracts in the next stage of the process.

Researched and written by World Nuclear News