Race to Zero will not let you build a reactor in Germany, and that is not a modelling shortcut — it is the law. Nuclear capacity in Europe is set by national statute far more than by cost, and the map is unusually diverse: two constitutional-scale bans, one completed phase-out, one repeal, and a dozen countries actively expanding. The game reads these limits from site/data/countries-insights.json, which is why a slider can be pinned at 0 MW in one country and open to 6 GW in the next.
The countries that closed the door
Germany shut its last three reactors — Emsland, Isar 2 and Neckarwestheim 2 — on 15 April 2023. 2024 was the country's first full nuclear-free year and the 2025 coalition has not reversed the decision, so German nuclear capacity is 0 GW and stays there in every scenario you can build.
Austria goes further: after the 1978 referendum the 1999 Federal Constitutional Act for a Nuclear-Free Austria made the ban constitutional. The finished Zwentendorf plant never produced a kilowatt-hour. Italy ended nuclear generation after the 1987 referendum and reaffirmed it in 2011; an enabling law adopted in February 2025 begins to reverse the ban, but with implementing decrees due around 2027 no Italian nuclear capacity exists this decade. Ireland still has a statutory prohibition in the Electricity Regulation Act 1999, and Spain is running the opposite way from the expanders: the 2019 closure calendar to 2035 stands, softened only by the renewal of the Almaraz licence to June 2030.
The countries that reopened it
Denmark is the cleanest example of policy moving faster than plant: the Folketing repealed its 1985 anti-nuclear resolution in May 2025 and commissioned an analysis of small modular reactor options. There is still no project and no capacity, so a Danish nuclear slider stays at zero — a useful reminder that legality and availability are different constraints. Belgium abrogated its 2003 phase-out law in May 2025, extended Doel 4 and Tihange 3 to 2035, and now targets roughly 4 GW. Switzerland's four operating units have no lifetime limit, and the Federal Council's 2025 proposal to lift the new-build ban is still before parliament.
The countries that are building
France remains the anchor at 61.4 GW across 56 reactors plus Flamanville 3, with an EPR2 programme of six reactors and an option for eight more. Sweden (7 GW) added a state risk-sharing framework in 2025 and Vattenfall has selected SMRs for about 1.5 GW at Ringhals. Finland (4.4 GW) eased licensing with a 2026 amendment to the Nuclear Energy Act. Czechia (4.35 GW) contracted Dukovany 5 in 2024–25, Poland filed the construction licence for three AP1000 units at Lubiatowo-Kopalino in March 2026, and the Netherlands confirmed life extension for Borssele while planning new large units. Every one of those projects lands in the mid-2030s at the earliest.
What that means when you play
Nuclear is the one dial in the game where the constraint is a parliament rather than a learning curve. It is also the dial that behaves least like the others: a reactor runs at a capacity factor of 70–90 %, so a gigawatt of nuclear displaces far more coal than a gigawatt of solar, while its LCOE is set almost entirely by construction cost and financing rather than by fuel. If a scenario needs firm, low-carbon output and the nuclear slider will not move, the honest answers are storage, interconnection and demand-side flexibility — the same three answers real system operators reach for. And when a country does allow expansion, remember the lead time: a licence application in 2026 is electricity in 2036, which is well past the horizon of most targets you are trying to hit.
Policy status and capacities in this lesson come from site/data/countries-insights.json (nuclear_policy, policy status as of August 2026, capacity as of 2025), compiled from Ember's Yearly Electricity Data, World Nuclear Association country profiles and World Nuclear News reporting. Only entries flagged verified are quoted here.