As part of a big energy policy shift announced by Prime Minister Fumio Kishida, Japan plans to sanction the building of nuclear power plants for the first time since the disaster at the Fukushima nuclear plant following the country’s March 2011 earthquake and subsequent tsunami.
The Ministry of Economy, Trade and Industry (METI) revealed details of the plans this week, saying they would also create a path for some reactors to remain in operation for more than 60 years.
In preparation for the new building project, Mitsubishi Heavy Industries (MHI) in October detailed plans for next-generation nuclear plants, while Hitachi has also begun to explain its approach as rivals anticipate new orders.
But what will be different – and safer – about the new plants and how would they help Japan’s energy mix? Here are four things to know.
What kind of plants are being developed, and when?
The two companies are competing to develop what they call innovative light-water reactors – plants with enhanced safety features based on existing large, light-water reactors. Both companies hope to commercialise new plants by the mid-2030s.
The basic design is “80% complete”, according to Akihiko Kato, head of the nuclear division at MHI. Hitachi says the company is already working on developing the equivalent through its General Electric (GE) joint venture, Hitachi GE Nuclear Energy.
Both companies are also developing other types, including so-called small modular reactors with a power output of up to 300 megawatts per unit.
MHI is also working on a high-temperature gas reactor (HTGR) – a type of reactor that can mass produce hydrogen as well as power.
Hitachi, in conjunction with GE of the US, is developing a fast reactor that can reuse nuclear fuel, while MHI intends to license HTGR technology – which includes equipment that replaces fuels or detects damaged fuel – to US startup TerraPower.
None of these new reactor types is expected to be commercially available until at least the 2030s. New safety standards will also be required.
Will the new plants be safe?
The Fukushima nuclear accident occurred when a tsunami damaged the plant’s control systems and disabled cooling functions that were supposed to safely halt operations and prevent the release of radioactivity.
The key feature of the light-water reactors is what Hitachi calls a passive reactor cooling system, which can function without external power in case of a disaster.
The system uses natural processes for cooling and eliminating toxic substances. For example, if a core meltdown occurs and nuclear fuel leaks through the reactor vessel, a core catcher will be installed under the vessel so the fuel does not leak outside the building.
Even if radioactive gases in the reactor have to be released as a last resort to prevent vessel damage, an exhaust filter is designed to break down toxic substances into safer components.
MHI’s planned 1,200-MW plants would be built partially underground to minimise damage from earthquakes, plane crashes or other disasters. Plants would be built high enough to avoid tsunami damage. Outer walls would be twice as thick as before and communications networks would be designed to prevent cyberattacks.
Professor Tadashi Narabayashi of the Tokyo Institute of Technology describes the new type of reactors as a “compilation of nuclear technology” that incorporates lessons learned from the Fukushima nuclear accident.
But the plans will be expensive and may need government funding. “I wish we had more support from the government, especially on finance,” said MHI’s Kato.
How would the new government policy change Japan’s energy supply?
Nuclear power – considered one of the cleanest sources of electricity from a sustainability perspective – is likely to account for an increasing share of Japan’s energy mix. According to METI, nuclear power accounted for only 6% of Japan’s electricity demand of approximately 100 million kWh in fiscal 2019. This is expected to increase to between 20%-22% by fiscal 2030. Renewable energy’s share will increase from 18% in 2019 to 36%-38% in 2030.
One feature of the new-generation plants is that they would be easier to run for short bursts or at reduced output. This would make them easier to use alongside renewable energy sources such as wind and solar power, which are dependent on weather and time of day.
Japan’s ability to develop renewable energy is limited by its relatively small available land and deep offshore waters. Reliance on coal to provide a stable power source clashes with the aim of reducing carbon emissions.
That is why nuclear power – which combines a stable supply and low generation costs with decarbonisation – is again becoming a feasible alternative.
Even before Japan builds new nuclear power plants it needs to restart some existing facilities while dispelling doubts about their safety since the Fukushima accident. Getting the approval of local authorities, which ultimately bear the risk of accidents, is also essential.
What is happening in the world regarding next-generation nuclear plants?
In July, the European Union identified nuclear power plants as green projects in its investment “taxonomy”. The plants are classified as sustainable if they are licensed for construction by 2045, provided they do not significantly harm the environment, including impacts on biodiversity and water. The EU’s move is likely to spur the development of next-generation nuclear power plants.
The UK has announced plans for up to eight new large reactors by 2050. The government will provide £210 million (US$236 million) for Rolls-Royce to develop small modular reactors. In addition, the government has plans for HTGRs in the 2030s and intends to adopt Japanese technology.
In France, the government will invest €1 billion in research and development activities for small modular reactors. There is also interest in low-cost nuclear power plants in Eastern Europe, where rising natural gas prices are a particular threat due to Russia’s reduced gas supplies to Europe.
US startup NuScale Power will begin operations of its first power plant in northwest Idaho in 2029. Each unit will have an output of less than 100 MW, and several units will be combined depending on local demand.
Japan’s IHI, the world’s leading manufacturer of containment vessels for nuclear reactors, has invested in the company together with plant builder JGC Holdings and the Japan Bank for International Cooperation.