Last month marked half a century since the first light-water nuclear reactor entered into service in Japan. Since then, nuclear power in Japan has gone through major ups and downs, from growing in popularity in the 1970s all the way to existential concerns about the future of Japanese electricity generation in the post-Fukushima era.

In this article, we take a deeper look into the history of nuclear power generation in Japan, as well as its present and future.

Nuclear Power as Japan’s National Strategic Priority

Japan’s nuclear research program first began in 1954 and in 1963 Japan began operating its first reactor that produced electricity. This first reactor was a boiling water reactor operated by Japan Power Demonstration Reactor.

However, it was not until 1966 that Japan got its first commercial reactor, Tokai 1 built by the British GEC. While this reactor was gas-cooled, afterwards, Japan used only light-water nuclear reactors fueled with enriched uranium. The first commercial light-water nuclear reactor was established by Japan Atomic Power Co. in Tsuruga, Fukui in 1970. By the end of the 1970s, Japan had its own ability to produce nuclear power plants.

The initial popularity of Japan’s nuclear plants was a side effect of the 1973 oil shock.

Japan’s nuclear development was preceded by the country’s rapid industrialization in the wake of World War II. As its energy needs grew, Japan became dependent on fossil fuel imports, particularly on oil from the Middle East. Once the oil shock hit as the Organization of Arab Petroleum Exporting Countries declared an oil embargo, oil prices skyrocketed and left Japan to attempt to manage an energy crisis.

The dire situation highlighted Japan’s dependence on imports for its energy and caused a shift in policy towards lesser dependence on oil imports. Though at the time of the oil shock Japan already had 5 reactors in operation, post-oil shock, nuclear plant construction became an even more important part of its energy policy. Japan has since considered nuclear energy a national strategic priority.

With the focus on diversification and the perception of nuclear energy as an essential future energy resource, Japan turned to the United States for assistance. Japanese utilities bought the United States’ designs and cooperated with domestic companies to build them. That allowed for similar plants to be built in Japan under license from the US companies. Hitachi Co. Ltd, Toshiba Co. Ltd, and Mitsubishi Co. Ltd. designed and built reactors themselves.

In 1970, three light water reactors using enriched uranium came online. Over the next 40 years, nuclear power plants were steadily built. 30 boiling water reactors and 24 pressurized water reactors have been put into operation since then. As Japan’s nuclear expertise grew, it also started to export its own technology to other countries.

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Controversies in the Pre-Fukushima Era

Though nuclear power plants were initially recognized as beneficial to Japanese society, several controversies have plagued the country’s nuclear power plants as their production continued.

As the only country that has directly experienced the use of nuclear weapons, Japan is sensitive to the use of nuclear fuel and has often been said to have a “nuclear allergy.” As such, it is no surprise that the Japanese public is strongly opposed to anything related to nuclear weapons proliferation.

Japan has a full fuel cycle that includes enrichment and reprocessing, which creates the worry of Japan having the materials to create nuclear weapons if it decided to do so. In fact, in nuclear non-proliferation circles, Japan is sometimes referred to as a “latent nuclear weapons state.”

The country aims to maximize the utilization of imported nuclear fuel by reprocessing spent uranium and fabricating mixed-oxide fuel containing plutonium. There have been protests in Japan about its commercial enrichment plant at Rokkasho, from both safety and non-proliferation perspectives, and it has also garnered international attention.

Outside of Japan, the Three Mile Island nuclear power plant accident which happened in 1979 also had a negative impact on Japanese public perception. Witnessing the partial meltdown created a sense of unease with the public that something similar could happen in Japan.

In 1981 there was an incident with a reactor at Tsuruga involving the leak of radioactive material. The material leaked into the sea due to a radioactive sludge tank overflowing, and the operator failed to inform the public of the issue in a timely manner. This did nothing to alleviate the public’s distrust of nuclear energy.

In December 1995, there was another incident, this time at the Monju Nuclear Power Plant, where a sodium leak could have caused an explosion. The sodium reached a temperature higher than anticipated by engineers and if it had leaked in the reactor, it could have caused an explosion that would likely have released radiation.

In 1997 and 1999, a pair of accidents, known as the Tokaimura nuclear accidents, took place in Tokai Village in Ibaraki. During the first, less serious accident, a small explosion occurred in Donen nuclear power plant’s reprocessing plant. The second, more serious accident took place at a uranium reprocessing facility operated by Sumitomo Metal Mining’s subsidiary, JCO.

In 2004, a ruptured pipe at the Mihama Nuclear Power Plant burst with non-radioactive steam, killing 5 workers. Investigations revealed that the plant’s pipes had not been inspected for 28 years.

Finally, in 2007, a few years before the Fukushima accident, there was an incident at the Kashiwazaki-Kariwa Nuclear Power Plant when an earthquake damaged the facilities and led to concern about the safety of nuclear reactors in Japan. Several radioactive leaks were detected in the 6.8 magnitude earthquake and the plant was closed for well over a year.   

Besides such incidents and accidents, over the decades that nuclear power has been a significant source of energy in Japan, corruption has also damaged the reputation of nuclear plants.

Most notably, in 2002, it was revealed that several safety-related inspection checks were falsified in the 1980s and 1990s. Involved in the scandal was not just Tokyo Electric Power Company, which concealed cracking of components in its reactors’ pressure vessels, but also the Ministry of Economy, Trade and Industry (METI) due to its cooperation in covering up the incident.

Nuclear Power in Japan in the Post-Fukushima Era

The Fukushima Daiichi nuclear disaster on March 11, 2011 was naturally a pivotal moment for Japanese public perception of nuclear energy and for the country’s energy policy. Unsurprisingly, in the wake of the disaster, there were several protests against nuclear power plants.

In May 2011, two months after the disaster, only 17 of 54 commercial nuclear power reactors were in operation. Nine had been shut down during the earthquake and the rest were taken offline for inspections or following special requests from the prime minister to build tsunami and earthquake resistance. Over time, as plants shut down for maintenance, they did not come back online. Eventually, all 54 commercial reactors were shut down. 

With that, Japan’s energy landscape changed dramatically. Prior to Fukushima, 30% of Japan’s electricity generation came from nuclear reactors. As of today, the government’s plan is to get back to between 20% and 22% by 2030. Japan currently relies on imports for approximately 90% of its energy requirements.

In response to the disaster and the damage to public opinion, the Democratic Party of Japan (DPJ) set up the Energy and Environment Council to evaluate the current situation and as a result it advocated to completely phase-out nuclear power by 2040. This was seen as too extreme, and in the 2012 elections, the Liberal Democratic Party (LDP) took control.

Once in power, the LDP shut down the Energy and Environmental Council as well as the National Policy Institute. In their place, the party empowered the Advisory Committee for National Resources and Energy at METI to decide Japan’s energy plans. In October 2012, the Nuclear Regulation Authority (NRA) was created to replace the Nuclear and Industrial Safety Agency (NISA) and the Nuclear Safety Commission (NSC).

In order to restart nuclear power plants, operators would have to pass a safety assessment by the NRA as well as gain the approval of affected local governments. 

In April 2014, METI’s 4th Basic Energy Plan was adopted. It discussed a 20-year perspective that highlighted nuclear energy’s economic as well as environmental benefits. The 2015 Plan for Energy Generation to 2030 then established the goal of nuclear power comprising between 20% and 22% of all electricity generation. The 5th Basic Energy Plan, established in 2018, further discussed details of how to meet that goal.

Slowly, starting in August 2015, nuclear reactors have begun to come back online. At the moment, nine have been restarted and 18 more are waiting for restart approval.

So far, only pressurized water reactors have been restarted. Boiling water reactors must be approved by their prefectures because they use a filtered containment venting system that may be used to release radioactivity during an emergency to avoid hydrogen build-up that could create Fukushima-like explosions.

In order to be restarted, nuclear plants have to undergo two stages of stress tests to assess risk and safety. The first involves scenarios of natural disaster damage and the second involves scenarios of multiple disasters at once. Additionally, the plants require permission from their local governments to start and this can be an issue, especially with local judicial rulings.

Regulations and requirements constantly change, creating an additional barrier for restarting. Further, restarts also come with significant implementation costs.

The NRA further increased the efforts required to restart nuclear power plants with its set of anti-terrorism guidelines. Those require an additional emergency control room to be used in the event of a terrorist attack. The NRA has stated that plants that are building facilities to meet the new guidelines will not have their deadlines to do so extended.

This has affected nearly 10 reactors. Already this year, Kyushu Electric Power missed its deadline for the construction of its emergency facility at one reactor and was forced to shut it down.

Finally, just as in the pre-Fukushima era, corruption has been a persistent issue in the Japanese nuclear industry and continues to damage its reputation in the public eye. One such scandal took place as recently as in October 2019 when Kansai Electric Power Co. admitted to 20 employees having received gifts totaling 318.45 million yen (around 3 million US dollars) from a former deputy mayor of a town that hosted one of its reactors. 

Stay Tuned!

With the state of nuclear power plants in Japan constantly evolving, we plan to continue covering this topic through both shorter news articles as well as deeper dives into specific issues surrounding the topic.

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