Japan’s Ministry of Economy, Trade & Industry (METI) has introduced a draft target to replace nuclear power reactors that are due to be decommissioned by the 2040s with new plants. The plan aims to replace 2-5 reactors (2.2-5.5 GWe of capacity) by the 2040s, scaling up to a cumulative total of 11-14 reactors (12.7-16 GW of capacity) by the 2050s.
In 2023, Japan’s Cabinet approved a policy to allow new nuclear power reactors to be constructed and the operation of existing reactors to be extended from 40 to 60 years. It noted that by 2040, more than 3 GWe of existing reactors will reach 60 years of operation, after which “the supply capacity of existing reactors as decarbonised power sources will be significantly lost”.
Japan’s 7th Basic Energy Plan, adopted in February 2025, calls for nuclear electricity generation to increase from 8.5% in fiscal 2023 to about 20% in fiscal 2040. However, the new draft target is the first numerical goal for reactor replacement released since the March 2011 severe accident at the Fukushima Daiichi NPP.
The plan cements a formal shift away from Japan’s post-Fukushima stance of “reducing nuclear dependency”. The updated Strategic Energy Plan explicitly shifts to maximising the use of nuclear energy. Initial site surveys and considerations for the new next-generation reactors include Kansai Electric Power Co’s Mihama power station in Fukui Prefecture and Kyushu Electric Power Co’s Sendai complex in Kagoshima Prefecture. There are currently 24 reactors undergoing decommissioning work at 11 NPPs.
Power needs are rising exponentially due to the rapid domestic buildout of AI infrastructure, semiconductor manufacturing, and data centres. Without replacement, Japan faces a projected 5.5 GWe supply deficit by the 2040s. Japan caps reactor operating lifespans at 60 years. With 15 of its current reactors set to cross that threshold by 2050, Japan requires direct rebuilding to maintain grid stability.
Rebuilding nuclear infrastructure is also deemed essential to hitting Japan’s commitments of cutting emissions by 73% by 2040 and achieving net-zero emissions by 2050. METI noted that clear numerical targets are vital to provide long-term investment predictability and to foster and retain human resources within the nuclear engineering sector.
In a presentation outlining the proposal, METI said that “given that a similar pace of decline in installed capacity is expected from the 2060s onward, and that future electricity demand may increase more than anticipated, in order to ensure a stable supply, efforts under this guideline will be promoted with a view to replacing at least this amount of installed capacity”. METI noted the need “to present forecasts and a future vision from the perspectives of long-term investment in nuclear power, maintenance of the nuclear industry base, and development and securing of human resources”.
The draft proposal was submitted to the Advisory Committee for Natural Resources & Energy and is on track for Cabinet approval. To meet its parallel goal of generating 20% of its electricity mix from nuclear power by 2040, Japan is pushing to clear safety checks and bring more of its remaining suspended fleet back online.
The plan has implications for the power sector. Asset managers will need to plan for life cycles exceeding 60 years, while engineers will face increased demand for equipment ageing management and structural integrity programmes. Building up to 14 nuclear reactors will also require strengthening related industrial capabilities, expanding regulatory inspection programmes, and creating new opportunities for operation, maintenance, and life extension.
