Japan taps industry to build safer, more secure nuclear energy future

Project with Mitsubishi Heavy Industries marks shift in policy since Fukushima disaster over a decade ago

Japan is about to change course on energy policy following the Fukushima disaster in 2011 with a focus on developing safer nuclear reactors.

The country put a stop to the construction of new nuclear plants after a tsunami hit the eastern prefecture, home to the Fukushima Daiichi Nuclear Power Plant, resulting in the most severe nuclear accident since Chernobyl in 1986. Now many of Japan's reactors lie idle.

In pursuit of carbon neutrality by 2050 and energy security due to Russia's war in Ukraine, the Japanese government has been considering a return to "next-generation nuclear reactors equipped with new safety mechanisms."

With this shift, a new partnership led by Mitsubishi Heavy Industries with four power utilities – Kansai Electric, Hokkaido Electric Power, Shikoku Electric Power, and Kyushu Electric Power – to develop an "innovative light-water reactor based on existing units of the same type" to be launched by the mid-2030s, as reported by Nikkei Asia.

Kansai Electric Power said in a statement: "We have been studying the design of a next-generation, light-water reactor with improved safety and economy, and are working with Mitsubishi Heavy Industries."

The project builds on Mitsubishi Heavy's pressurized light-water reactor that has been used by the four power utilities. It will be capable of producing between 0.6 million and 1.2 million kilowatts of electricity.

The focus is on improving the control-rod drive mechanism, responsible for adjusting nuclear reaction, to halve output or bring the reactor back online in 17 minutes, about a quarter of the time it takes existing reactors.

Robustness is also crucial, with the design purported to withstand natural disasters, terrorist attacks, and aircraft crashes. "The companies want to reduce the reactor's probability of sustaining damage to less than 1 percent of current models by installing it underground and fortifying the outer walls of the containment vessel," Nikkei said.

Beneath the containment vessel, a "core catcher" will be installed to prevent molten fuel escaping in the event of a meltdown. Emergency power systems can then also used to cool the reactor will be strengthened and located on-site.

Mitsubishi Heavy is also working on smaller and more efficient nuclear plants capable of producing 0.3 million kilowatts, as well as high-temperature, gas-cooled reactors to produce hydrogen.

Prime Minister Fumio Kishida's "green transformation" council has also been tasked with examining how Japan's existing reactors could be upgraded to safer light-water units. Light-water reactors are cooled and moderated with ordinary water as opposed to those that use heavy water (deuterium oxide, D₂O).

Elsewhere, as the International Energy Agency does not believe 2050 carbon emission goals are achievable without nuclear power, there have been signs of innovation in small modular reactors (SMRs), notably in Britain, where Rolls-Royce has secured funding to build plants based on the design.

SMRs are much smaller than the current generation of nuclear reactors under construction and produce far less power. But what they lack in economies of scale, they make up for in modular design and off-site construction.

The International Atomic Energy Authority says that "prefabricated units of SMRs can be manufactured and then shipped and installed on-site, making them more affordable to build than large power reactors, which are often custom designed for a particular location, sometimes leading to construction delays. SMRs offer savings in cost and construction time, and they can be deployed incrementally to match increasing energy demand."

However, a study by Stanford University and the University of British Columbia concluded that SMRs may generate up to 35 times more waste to produce the same amount of power as a regular plant. The research and methodology was heavily contested by companies developing the technology.

In any case, a global surge in nuclear power could be on the cards as governments wake up to climate change and over-reliance on rogue states for their energy needs – as demonstrated by the Nord Stream pipeline crisis. ®