Small Modular Reactors

Small Modular Reactors (SMRs) are part of a new generation of nuclear power plant design being developed in several countries to supply small communities.

Other than residential electricity capacity – which could theoretically support a small city in the UK residential capacity and not much else, their design is also suggested for use in high-power industrial units.

The idea behind SMRs is that they will be pre-manufactured at a plant and brought to site fully constructed, which is optimal in remote areas. While the smaller power output of an SMR means that electricity will cost more per MW than it would from a larger reactor, the initial cost of building the plant is much less than that of constructing a more complex, large nuclear plant, making the SMR a smaller-risk venture for power companies than other nuclear power plants.

Small Modular Reactors (SMRs) have been a catalyst for renewed interest in the possibility of using smaller, simpler units for generating electricity from nuclear power. This interest is also driven both by a desire to reduce overall cost and to provide an alternative source of power to large grid systems.

Of the designs available to us here in the UK, the integrated pressurised water reactors are most technologically ready, such as those already used in submarines. There are estimated to be in the region of over 45 SMR designs under development in the US, Europe, China and elsewhere for various purposes [SOURCE: IAEA Advances in Small Modular Reactor Technology Developments].

The UK’s Penultimate Power and the Japanese Atomic Energy Agency  are working on a High Temperature Gas-cooled Reactor (HTGR),a nuclear reactor that uses graphite with a once-through uranium fuel cycle.  It is a design already operating in Japan, and is to be ‘walk away safe’.  It uniquely provides carbon-free heat up to 950oC for industrial processes, including green hydrogen at point of use via the sulphur-iodine process [2].

Moltex are an UK-Canadian venture who have developed a stable salt modular reactor ready for implementation. The liquid salt fuel mixture is contained within solid fuel assemblies. The fuel assemblies are then submerged in a pool of pure liquid salt coolant.

Others include the simple boiling water reactor design: BWRX-300, by Hitachi, the high temperature reactor design by Cavendish Nuclear or the larger units proposed by Rolls-Royce.






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