Novelties in light-water SMR designs suitable for Sweden’s future electricity production needs: Report ANItA project A2

Report, 2025

Land-based light-water-cooled and -moderated small modular reactors (SMRs) are one optionfor adding new nuclear capacity in Sweden. This project has investigated such SMRs andcompiled a shortlist of four SMRs that are deemed the most probable to be built for (mainly)electricity production in Sweden in the relatively near future. These SMRs are the boiling-water reactor GE Hitachi BWRX-300 and the pressurised-water reactors (PWRs) Rolls-RoyceSMR, Westinghouse AP300, and NuScale VOYGR.In the shortlisted SMRs, as well as in others, there are design features previously not used inSwedish reactors. Some of these features could have an impact on the licensability,constructability, and operability/maintainability of the SMRs and thus be barriers to deployingthe SMRs. Better understanding of such features, and therefore further investigation, or at leastclarification from the organisations developing the reactors, is necessary for successfulimplementation of SMRs in Sweden. The following were identified as novel features that needfurther investigation or clarification: increased modularity, enhanced natural circulation,increased passive safety, novel containment designs, smaller size (of the reactor and powerplant), integral PWRs, integral reactor isolation valves, novel types of water chemistry,novelties in the steam and power conversion system, increased load-following capability, drystorage of spent fuel, and novelties in severe accident mitigation and management. Regardinglicensability, all identified novel features except some of the novelties in water chemistry andin the steam and power conversion system are deemed to be in need of further investigation orclarification; regarding operability/maintainability, all identified novelties except some of thenovelties related to modularity, increased passive safety, containment design, and severeaccident mitigation and management are deemed to be in need of further investigation orclarification; and regarding constructability, the increased modularity, the novel containmentdesigns, the smaller size, and part of the novelties in the steam and power conversion systemare the novelties that are deemed to be in need of further investigation or clarification.