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

Rapport, 2025

Land-based light-water-cooled and -moderated small modular reactors (SMRs) are one option
for adding new nuclear capacity in Sweden. This project has investigated such SMRs and
compiled 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-Royce
SMR, Westinghouse AP300, and NuScale VOYGR.

In the shortlisted SMRs, as well as in others, there are design features previously not used in
Swedish reactors. Some of these features could have an impact on the licensability,
constructability, and operability/maintainability of the SMRs and thus be barriers to deploying
the SMRs. Better understanding of such features, and therefore further investigation, or at least
clarification from the organisations developing the reactors, is necessary for successful
implementation of SMRs in Sweden. The following were identified as novel features that need
further investigation or clarification: increased modularity, enhanced natural circulation,
increased passive safety, novel containment designs, smaller size (of the reactor and power
plant), integral PWRs, integral reactor isolation valves, novel types of water chemistry,
novelties in the steam and power conversion system, increased load-following capability, dry
storage of spent fuel, and novelties in severe accident mitigation and management. Regarding
licensability, all identified novel features except some of the novelties in water chemistry and
in the steam and power conversion system are deemed to be in need of further investigation or
clarification; regarding operability/maintainability, all identified novelties except some of the
novelties related to modularity, increased passive safety, containment design, and severe
accident mitigation and management are deemed to be in need of further investigation or
clarification; and regarding constructability, the increased modularity, the novel containment
designs, the smaller size, and part of the novelties in the steam and power conversion system
are the novelties that are deemed to be in need of further investigation or clarification.