Part 2 of 2 Parts (Please read Part 1 first)
     The report says that “One method of improving flexibility of nuclear power is to combine it with thermal storage. The higher temperatures produced by some AMRs (advanced modular reactors) make them particularly suited to production of hydrogen and other synthetic fuels, as well as heating for a large range of industrial applications. This potential is further exploited in several AMR conceptual designs that choose to incorporate molten salt thermal storage … this arrangement of a reactor plus thermal store opens the prospect of broader commercial uptake by end users, through considerable availability of economic, flexible, useful energy output, and should be investigated.”
     The report explains that the thermal storage concept follows experience with solar thermal power “where it has been proved effective and economic in countries with abundant sunshine … molten salts are used to store heat in large, insulated silos, and the molten salts are then run through steam generators or heat exchangers. The cooled molten salt is then stored in separate silos to be used in the next cycle … alternatively, the heat can be stored in large, insulated masses of cheap solid materials such as sand or gravel which are heated and depleted by molten salts, but this system has a lower thermal efficiency than the two-tank molten salt option … several AMR conceptual designs include molten salt thermal storage combined with energy conversion plants up to three times the capacity of the reactor system. At times of low electricity demand, energy is directed to the heat store; at times of high demand, this stored heat energy can be converted into electricity along with the reactor’s output. This allows continuous operation of a reactor plant while allowing unrestricted load following, including at very low levels of electricity delivery to the grid”.
     The report recommends that the U.K. government should prioritize research to allow in-depth investigation of the opportunities to use reactors with thermal storage. It also recommends that government assessments of the impact of new nuclear capacity should recognize and incorporate cogeneration applications. It goes on to say that “government and industry should aim to reduce the need for curtailment of renewable electricity by using cogenerated nuclear heat to power high-temperature electrolysis hydrogen production, in addition to short-term storage”, while “planning for future nuclear deployment should envisage an integrated system where nuclear and variable renewables work in harmony through cogeneration and energy storage, while planning around energy (not just electricity) infrastructure delivery should be fully coordinated to best ensure the UK has a functional whole system”.
     With respect to potential next steps, the report says that “further research and development into thermal energy storage technology is necessary, as the technology’s engineering feasibility is central to achieving the potential economic benefits of the Flexible Nuclear approach”.
     Zara Hodgson adds that “Our analysis indicates future promise for a flexible, fossil fuel free energy system that integrates the synergistic advantages of renewable energy and cogenerating nuclear energy, as the technologies become deployable in the system from now to 2030, then onto 2040, and finally full implementation by 2050. Capitalizing on the flexibility of nuclear energy to contribute more than just low-carbon electricity is a key innovation opportunity for the UK and offers leadership in international net-zero initiatives and enhanced energy security.”

University of Manchester