Nuclear power in Japan

Nuclear power generated 5.55% of Japan's electricity in 2023.[2]
The country's nuclear power industry was heavily influenced by the Fukushima accident, caused by the 2011 Tōhoku earthquake and tsunami. Before 2011, Japan was generating up to 30% of its electrical power from nuclear reactors.[3] After the Fukushima accident, all reactors were shut down temporarily. As of November 2024[update], of the 54 nuclear reactors present in Japan before 2011, there were 33 operable reactors but only 13 reactors in 6 power plants were actually operating.[3] A total of 24 reactors are scheduled for decommissioning or are in the process of being decommissioned.[4] Others are in the process of being reactivated, or are undergoing modifications aimed to improve resiliency against natural disasters; Japan's 2030 energy goals posit that at least 33 will be reactivated by a later date.[5]
The Fukushima accident hardened attitudes toward nuclear power. In June 2011, immediately after the accident, more than 80% of Japanese said they were anti-nuclear and distrusted government information on radiation,[6][7][8] but ten years later, in March 2021, only 11 percent of Japanese said they wanted that nuclear energy generation to be discontinued immediately. Another 49 percent were asking for a gradual exit from nuclear energy.[9] In February 2023, a survey by Asahi Shimbun showed that 51% of participants in Japan favored the restart of nuclear plant operations, with 42% opposed.[10]
History
[edit]Early years
[edit]
After the Atoms for Peace speech given by then-American President Eisenhower at the UN General Assembly in 1953, a total ban on nuclear research, imposed during the post-war occupation of Japan and continued after Japan regained sovereignty, was lifted. Future Prime Minister Yasuhiro Nakasone and his peers from the Kaishintō Party (a forerunner to the Liberal Democratic Party) drafted a 235-million-yen budget (the amount symbolically referencing uranium-235), which was approved by the Diet.[11]
Around the same time, the Atomic Energy Act of 1954 was enacted in America, and Japan received condensed uranium from the country in 1955. Two experimental reactors, JRR-1 (built by North American Aviation's nuclear division) and JRR-2 (largely based on Chicago Pile-5), were constructed. A much more powerful experimental reactor JRR-3 was completed in 1962 by a consortium led by Hitachi, the first experimental reactor to be fully designed and built in Japan.[12] Also in 1955, Nakasone's group drafted the Atomic Energy Basic Law, which was enacted in Japan to promote nuclear power while limiting activities strictly to peaceful purposes.[13] The Japanese Atomic Energy Commission was established as a regulatory body, with its first chair, Matsutarō Shōriki, a newspaper magnate, also being a key promoter of nuclear power in Japan.
A prototype nuclear power station, JPDR, began power generation on 26 October 1963.[14] Japan's first commercial nuclear power plant, the Tōkai Nuclear Power Plant, was built using main components imported from the General Electric Company in the UK and was connected to the grid on 25 July 1966. This reactor remains the only Magnox reactor ever built on Japanese soil.[15] In 1969, the first nuclear-powered ship in Japan (and the fourth in the world), Mutsu, was launched by Mitsubishi Heavy Industries (reactor) and IHI (hull).[16]
Light water reactors
[edit]
General Electric offered light water reactors at a discounted price as soon as Yasuhiro Nakasone, then the Minister of Science and Technology, began revising the country's nuclear power strategy in 1961. This offer was accepted, and Tsuruga-1 was commissioned in March 1970 as Japan's first BWR.[17] GE teamed up with Hitachi and Toshiba to build BWRs, while Westinghouse collaborated with Mitsubishi Heavy Industries (MHI) to promote PWRs. By the late 1970s, these companies began constructing plants independently. All nuclear reactors built in Japan have been either BWRs or PWRs, with Hitachi and Toshiba (which later acquired Westinghouse's nuclear division to build PWRs as well) still responsible for the former and MHI for the latter.[18]
Developments in nuclear power since that time have seen contributions from Japanese companies and research institutes on the same level as the other big users of nuclear power. From the early 1970s to the present, the Japanese government promoted the siting of nuclear power plants through a variety of policy instruments involving soft social control and financial incentives.[19] By offering large subsidies and public works projects to rural communities and by using educational trips, junkets for local government officials, and OpEds written as news by pro-nuclear supporters, the central government won over the support of depopulating, hard-on-their-luck coastal towns, and villages.
Later years
[edit]Japan's nuclear industry was not hit as hard by the effects of the Three Mile Island accident (TMI) or the Chernobyl disaster as some other countries. Construction of new plants continued to be strong through the 1980s and 1990s. While many new plants had been proposed, all were subsequently canceled or never brought past initial planning. Cancelled plant orders include:
- The Hōhoku Nuclear Power Plant at Hōhoku, Yamaguchi – 1994
- The Kushima Nuclear Power Plant at Kushima, Miyazaki – 1997
- The Ashihama Nuclear Power Plant at Ashihama, Mie – 2000 (the first Project at the site in the 1970s was completed at Hamaoka as Unit 1&2)
- The Maki Nuclear Power Plant at Maki, Niigata (Kambara) – Canceled in 2003
- The Suzu Nuclear Power Plant at Suzu, Ishikawa – 2003
Starting in the mid-1990s there were several nuclear-related accidents and cover-ups in Japan that eroded public perception of the industry, resulting in protests and resistance to new plants. These accidents included the Tokaimura nuclear accident, the Mihama steam explosion, cover-ups after an accident at the Monju reactor, among others, more recently the Chūetsu offshore earthquake aftermath. While exact details may be in dispute, it is clear that the safety culture in Japan's nuclear industry has come under greater scrutiny.[20]
2000s
[edit]On 18 April 2007, Japan and the United States signed the United States-Japan Joint Nuclear Energy Action Plan, aimed at putting in place a framework for the joint research and development of nuclear energy technology.[21]
Each country will conduct research into fast reactor technology, fuel cycle technology, advanced computer simulation and modeling, small and medium reactors, safeguards and physical protection; and nuclear waste management.[22] In March 2008, Tokyo Electric Power Company announced that the start of operation of four new nuclear power reactors would be postponed by one year due to the incorporation of new earthquake resistance assessments. Units 7 and 8 of the Fukushima Daiichi plant would now enter commercial operation in October 2014 and October 2015, respectively. Unit 1 of the Higashidori plant is now scheduled to begin operating in December 2015, while unit 2 will start up in 2018 at the earliest.[23] As of September 2008, Japanese ministries and agencies were seeking an increase in the 2009 budget by 6%. The total requested comes to 491.4 billion Japanese yen (US$4.6 billion), and the focuses of research are the development of the fast breeder reactor cycle, next-generation light water reactors, the Iter project, and seismic safety.[24]
Fukushima accident and aftermath
[edit]
An energy white paper, approved by the Japanese Cabinet in October 2011, says "public confidence in the safety of nuclear power was greatly damaged" by the Fukushima accident in March 2011, and calls for a reduction in the nation's reliance on nuclear power. It also omits a section on nuclear power expansion that was in the previous year's policy review.[25] Nuclear Safety Commission Chairman Haruki Madarame told a parliamentary inquiry in February 2012 that "Japan's atomic safety rules are inferior to global standards and left the country unprepared for the Fukushima nuclear disaster last March". There were flaws in, and lax enforcement of, the safety rules governing Japanese nuclear power companies, and this included insufficient protection against tsunamis.[26]
On 6 May 2011, Prime Minister Naoto Kan ordered the Hamaoka Nuclear Power Plant to be shut down as an earthquake of magnitude 8.0 or higher is likely to hit the area within the next thirty years.[27][28][29][30][31]
As of 27 March 2012, Japan had only one out of 54 nuclear reactors operating; the Tomari-3, after the Kashiwazaki-Kariwa 6 was shut down.[32] The Tomari-3 was shut down for maintenance on 5 May, leaving Japan with no nuclear-derived electricity for the first time since 1970, when the country's then-only two reactors were taken offline for five days for maintenance.[33] On 15 June 2012, approval was given to restart Ōi Units 3 and 4[34] which could take six weeks to bring them to full operation. On 1 July 2012, unit 3 of the Ōi Nuclear Power Plant was restarted. This reactor can provide 1,180 MW of electricity.[35][36] On 21 July 2012 unit 4 was restarted, also 1,180 MW.[37] The reactor was shut down again on 14 September 2013, again leaving Japan with no operating power reactors.[38]

Operating reactors, building new reactors Operating reactors, planning new build No reactors, building new reactors No reactors, new in planning Operating reactors, stable Operating reactors, decided on phase-out Civil nuclear power is illegal No reactors |
Government figures in the 2014 Annual Report on Energy show that Japan depended on imported fossil fuels for 88% of its electricity in fiscal year 2013, compared with 62% in fiscal 2010. Without significant nuclear power, the country was self-sufficient for just 6% of its energy demand in 2012, compared with 20% in 2010. The additional fuel costs to compensate for its nuclear reactors being idled was ¥3.6 trillion. In parallel, domestic energy users have seen a 19.4% increase in their energy bills between 2010 and 2013, while industrial users have seen their costs rise 28.4% over the same period.[39]
In 2018 the Japanese government revised its energy plan to update the 2030 target for nuclear energy to 20%-22% of power generation by restarting reactors, compared to LNG 27%, coal 25%, renewables 23% and oil 3%. This would reduce Japan's carbon dioxide emissions by 26% compared to 2013, and increase self-sufficiency to about 24% by 2030, compared to 8% in 2016.[40]
Since the Fukushima nuclear accident, Japan has restarted twelve reactors and fifteen more have applied to restart, including two that are under construction. Amid the Russian invasion of Ukraine, Japan's Prime Minister announced the restart of nine units by winter 2022 and seven more by summer 2023.[10]
Investigations on the Fukushima accident
[edit]The National Diet of Japan Fukushima Nuclear Accident Independent Investigation Commission (NAIIC) is the first independent investigation commission by the National Diet in the 66-year history of Japan's constitutional government. NAICC was established on 8 December 2011 with the mission to investigate the direct and indirect causes of the Fukushima nuclear accident. NAICC submitted its inquiry report to both houses on 5 July 2012.[a][41]
The 10-member commission compiled its report based on more than 1,167 interviews and 900 hours of hearings.[42][43] It was a six-month independent investigation, the first of its kind with wide-ranging subpoena powers in Japan's constitutional history, which held public hearings with former Prime Minister Naoto Kan and Tokyo Electric Power Co's former president Masataka Shimizu, who gave conflicting accounts of the disaster response.[44] The commission chairman, Kiyoshi Kurokawa, declared with respect to the Fukushima nuclear incident: "It was a profoundly man-made disaster – that could and should have been foreseen and prevented."[45] He added that the "fundamental causes" of the disaster were rooted in "the ingrained conventions of Japanese culture."[46] The report outlines errors and willful negligence at the plant before the 2011 Tōhoku earthquake and tsunami on 11 March 2011 and a flawed response in the hours, days, and weeks that followed. It also offers recommendations and encourages Japan's parliament to "thoroughly debate and deliberate" the suggestions.[47]
Post-Fukushima nuclear policy
[edit]Japan's new energy plan, approved by the Liberal Democratic Party cabinet in April 2014, calls nuclear power "the country's most important power source".[51] Reversing a decision by the previous Democratic Party, the government will re-open nuclear plants, aiming for "a realistic and balanced energy structure". In May 2014 the Fukui District Court blocked the restart of the Oi reactors.[52] In April 2015 courts blocked the restarting of two reactors at the Takahama Nuclear Power Plant but permitted the restart of two reactors at the Sendai Nuclear Power Plant.[53] The government hopes that nuclear power will produce 20% of Japan's electricity by 2030.[53]
As of June 2015, approval was being sought from the new Nuclear Regulatory Agency for 24 units to restart, of the 54 pre-Fukushima units. The units also have to be approved by the local prefecture authorities before restarting.[54]
In July 2015 fuel loading was completed at the Sendai-1 nuclear plant, it restarted 11 August 2015 and was followed by unit 2 on 1 November 2015. Japan's Nuclear Regulatory Authority approved the restart of Ikata-3 which took place on 19 April 2016, this reactor is the fifth to receive approval to restart.[55] The Takahama Nuclear Power Plant unit 4 restarted in May 2017 and unit 3 in June 2017. And by 2023, Unit 1 and 2 of Takahama also restarted.[56]
In November 2016 Japan signed a nuclear cooperation agreement with India. Japanese nuclear plant builders saw this as potential lifeline given that domestic orders had ended following the Fukushima disaster, and India is proposing to build about 20 new reactors over the next decade. However, there is Japanese domestic opposition to the agreement, as India has not agreed to the Treaty on the Non-Proliferation of Nuclear Weapons.[57]
In 2014, following the failure of the prototype Monju sodium-cooled fast reactor, Japan agreed to cooperate in developing the French ASTRID demonstration sodium-cooled fast breeder reactor.[58][59] As of 2016, France was seeking the full involvement of Japan in the ASTRID development.[59][60]
In 2015, the Agency for Natural Resources and Energy changed the accounting provisions of the Electricity Business Act, so companies can account for decommissioning costs in ten yearly installments rather than a one-time charge. This will encourage the decommissioning of older and smaller nuclear units, most of which have not restarted since 2011.[61]
In 2022, during the global energy crisis which greatly increased the cost of imported fossil fuels, Japan's prime minister announced the building of safer next-generation nuclear reactors and restarting idle existing plants would be considered. In 2022 ten reactors were operational producing about 5% of Japan's electricity.[62]
In December 2022, Japan's Nuclear Regulation Authority (NRA) approved a draft-rule allowing nuclear reactors to operate beyond 60 years by excluding inspection downtimes. This was part of a policy at enhancing nuclear reactor use, including restarting many, extending older units' lives, and developing new reactor technologies. In February 2023, the cabinet approved this policy and the construction of new reactors. By May 2023, a law was enacted to officially omit shutdown periods from the 60-year limit, subject to the economy minister's approval. The law also required the NRA to perform inspections every 10 years for reactors over 30 years of operation.[10]
Seismicity
[edit]Japan has had a long history of earthquakes and seismic activity, and destructive earthquakes, often resulting in tsunamis, occur several times a century. Due to this, concern has been expressed about the particular risks of constructing and operating nuclear power plants in Japan. Amory Lovins has said: "An earthquake-and-tsunami zone crowded with 127 million people is an unwise place for 54 reactors".[63] To date, the most serious seismic-related accident has been the Fukushima Daiichi nuclear disaster, following the 2011 Tōhoku earthquake and tsunami.
Professor Katsuhiko Ishibashi, one of the seismologists who have taken an active interest in the topic, coined the term genpatsu-shinsai (原発震災), from the Japanese words for "nuclear power" and "quake disaster" to express the potential worst-case catastrophe that could ensue.[64][65] Dr Kiyoo Mogi, former chair of the Japanese Coordinating Committee for Earthquake Prediction,[66] has expressed similar concerns, stating in 2004 that the issue 'is a critical problem which can bring a catastrophe to Japan through a man-made disaster'.[67][68]
Warnings from Kunihiko Shimazaki, a professor of seismology at the University of Tokyo, were also ignored. In 2004, as a member of an influential cabinet office committee on offshore earthquakes, Mr. Shimazaki "warned that Fukushima's coast was vulnerable to tsunamis more than twice as tall as the forecasts of as much as five meters put forth by regulators and Tokyo Electric".[69] Minutes of the meeting on 19 February 2004, show that the government bureaucrats running the committee moved quickly to exclude his views from the committee's final report. He said the committee did not want to force Tokyo Electric to make expensive upgrades at the plant.[69]
Hidekatsu Yoshii, a member of the House of Representatives for Japanese Communist Party and an anti-nuclear campaigner, warned in March and October 2006 about the possibility of the severe damage that might be caused by a tsunami or earthquake.[70] During a parliamentary committee in May 2010 he made similar claims, warning that the cooling systems of a Japanese nuclear plant could be destroyed by a landslide or earthquake.[70] In response, Yoshinobu Terasaka, head of the Nuclear and Industrial Safety Agency, replied that the plants were so well designed that "such a situation is practically impossible".[70] Following damage at the Kashiwazaki-Kariwa Nuclear Power Plant due to the 2007 Chūetsu offshore earthquake, Kiyoo Mogi called for the immediate closure of the Hamaoka Nuclear Power Plant,[66][71] which was knowingly built close to the centre of the expected Tōkai earthquake.[67] Katsuhiko Ishibashi previously claimed, in 2004, that Hamaoka was "considered to be the most dangerous nuclear power plant in Japan".[72]
The International Atomic Energy Agency (IAEA) has also expressed concern. At a meeting of the G8's Nuclear Safety and Security Group, held in Tokyo in 2008, an IAEA expert warned that a strong earthquake with a magnitude above 7.0 could pose a 'serious problem' for Japan's nuclear power stations.[73] Before Fukushima, "14 lawsuits charging that risks had been ignored or hidden were filed in Japan, revealing a disturbing pattern in which operators underestimated or hid seismic dangers to avoid costly upgrades and keep operating. But all the lawsuits were unsuccessful".[74] Underscoring the risks facing Japan, a 2012 research institute investigation has "determined there is a 70% chance of a magnitude-7 earthquake striking the Tokyo metropolitan area within the next four years, and 98% over 30 years". The March 2011 earthquake was a magnitude 9.[75]
Design standards
[edit]Between 2005 and 2007, three Japanese nuclear power plants were shaken by earthquakes that far exceeded the maximum peak ground acceleration used in their design.[76] The tsunami that followed the 2011 Tōhoku earthquake, inundating the Fukushima I Nuclear Power Plant, was more than twice the design height,[77] while the ground acceleration also slightly exceeded the design parameters.[78]
In 2006 a Japanese government subcommittee was charged with revising the national guidelines on the earthquake-resistance of nuclear power plants, which had last been partially revised in 2001,[79] resulting in the publication of a new seismic guide – the 2006 Regulatory Guide for Reviewing Seismic Design of Nuclear Power Reactor Facilities.[79] The subcommittee membership included Professor Ishibashi, however his proposal that the standards for surveying active faults should be reviewed was rejected and he resigned at the final meeting, claiming that the review process was 'unscientific'[66][80] and the outcome rigged[80][81] to suit the interests of the Japan Electric Association, which had 11 of its committee members on the 19-member government subcommittee.[81] Ishibashi has subsequently claimed that, although the new guide brought in the most far-reaching changes since 1978, it was 'seriously flawed' because it underestimated the design basis of earthquake ground motion.[64] He has also claimed that the enforcement system is 'a shambles'[64][76] and questioned the independence of the Nuclear Safety Commission after a senior Nuclear and Industrial Safety Agency official appeared to rule out a new review of the NSC's seismic design guide in 2007.[64]
Following the publication of the new 2006 Seismic Guide, the Nuclear and Industrial Safety Agency, at the request of the Nuclear Safety Commission, required the design of all existing nuclear power plants to be re-evaluated.[82]
Geological surveys
[edit]The standard of geological survey work in Japan is another area causing concern. In 2008 Taku Komatsubara, a geologist at the National Institute of Advanced Industrial Science and Technology alleged that the presence of active faults was deliberately ignored when surveys of potential new power plant sites were undertaken, a view supported by a former topographer.[83] Takashi Nakata, a seismologist from the Hiroshima Institute of Technology has made similar allegations and suggests that conflicts of interest between the Japanese nuclear industry and the regulators contribute to the problem.[81]
A 2011 Natural Resources Defense Council report that evaluated the seismic hazard to reactors worldwide, as determined by the Global Seismic Hazard Assessment Program data, placed 35 of Japan's reactors in the group of 48 reactors worldwide in very high and high seismic hazard areas.[84]
Nuclear power plants
[edit]As of January 2022 there are 33 operable reactors in Japan, of which 12 reactors are currently operating.[85] Additionally, 5 reactors have been approved for restart and further 8 have restart applications under review.