History

In 1954, Japan budgeted 230 million yen for nuclear energy, marking the beginning of the program. The Atomic Energy Basic Law limited activities to only peaceful purposes.
The first nuclear reactor in Japan was built by the UK's GEC. In the 1970s the first Light Water Reactors were built in cooperation with American companies. These plants were bought from U.S. vendors such as General Electric or Westinghouse with contractual work done by Japanese companies, who would later get a license themselves to build similar plant designs. Developments in nuclear power since that time has seen contributions from Japanese companies and research institutes on the same level as the other big users of nuclear power.
Robert Jay Lifton has asked how Japan, after its experience with the atomic bombings of Hiroshima and Nagasaki, could "allow itself to draw so heavily on the same nuclear technology for the manufacture of about a third of its energy". He says:
There was resistance, much of it from Hiroshima and Nagasaki survivors. But there was also a pattern of denial, cover-up and cozy bureaucratic collusion between industry and government, the last especially notorious in Japan but by no means limited to that country. Even then, pro-nuclear power forces could prevail only by managing to instill in the minds of Japanese people a dichotomy between the physics of nuclear power and that of nuclear weapons, an illusory distinction made not only in Japan but throughout the world.
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, 1990s, and up to the present day. However, 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 accidents 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.

Canceled plant orders include:

• The Maki NPP at Maki, Niigata (Kambara)—Canceled in 2003
• The Kushima NPP at Kushima, Miyazaki—1997
• The Ashihama NPP at Ashihama, Mie—2000
• The Hōhoku NPP at Hōhoku, Yamaguchi—1994
• The Suzu NPP at Suzu, Ishikawa—2003
Note that the Suzu NPP plant proposal is said to be "frozen", meaning that it may continue sometime in the future if economic factors turn more in its favor, though there has been no sign of this happening.

These cancellations reflect to some degree the safety concerns that surfaced after the Monju cover-up (1995) and the Tokaimura accident (1999) and could be compared to the situation in the United States where there was a large number of plant order cancellations after TMI and the Chernobyl disaster. However, it is important to note that most cancellations in Japan are a result of 10, 15, or more years of postponed work and poor support. Through the same time period there were also some new plants connected to the grid, and as of 2007, construction is in progress on several other plants. Japan has thus yet to see a complete break in the construction of new nuclear plants, which has happened in the United States and France.
The Japanese government has maintained strong support for nuclear power. After the Tokaimura accident, many reorganizations of the government funded research organizations occurred and stricter controls were enforced, but the size and scope of research in nuclear power topics has continued to expand. While the number of reactors is expected to increase, the focus of new developments will shift to the advanced fuel cycle and next generation plants. Japan plans to be a major player in the Global Nuclear Energy Partnership and has joined the ITER project. Furthermore, a United States-Japan Joint Nuclear Energy Action Plan has also been created, which is indicative of the commitment the Japanese government has to new nuclear technologies.
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 on 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.
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 (4.6 billion USD), and the focuses of research are development of the fast breeder reactor cycle, next-generation light water reactors, the Iter project, and seismic safety.

International cooperation

The nuclear industry in Japan has been highly affected by its U.S. counterpart. Through the late 1990s to present day, the industry has become confident that the United States would see construction of new nuclear plants. Hoping to take advantage of that, along with other opening markets, joint venture agreements between the major nuclear fuel vendors occurred in 1999, 2006, and 2007, following from the legacy of co-operation that began when Japan imported Western technology to jump start its nuclear fleet.
On April 18, 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. 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.

NUCLEAR POWER IN JAPAN

Since 1973, nuclear energy has been a national strategic priority in Japan, as the nation is heavily dependent on imported fuel, with fuel imports accounting for 61% of energy production. There has been concern about the ability of Japan's nuclear plants to withstand seismic activity. The Kashiwazaki-Kariwa Nuclear Power Plant was completely shut down for 21 months following an earthquake in 2007.
Following an earthquake, tsunami, and the failure of cooling systems at the Fukushima I Nuclear Power Plant on March 11, 2011, a nuclear emergency was declared. This was the first time a nuclear emergency had been declared in Japan, and 140,000 residents within 20 km of the plant were evacuated. The amount of radiation released is unclear, as the crisis is ongoing
On 6 May 2011, Prime Minister Naoto Kan ordered the Hamaoka Nuclear Power Plant be shut down as an earthquake of magnitude 8.0 or higher is likely to hit the area within the next 30 years. Kan wanted to avoid a possible repeat of the Fukushima disaster.



Nuclear power plants
There are 55 operating nuclear reactors in Japan with a number of others in construction or being planned. For a list, see List of nuclear reactors or List of power stations in Japan. Following the Fukushima I nuclear accidents Prime Minister Naoto Kan has announced that all 6 of the reactors at the Fukushima I Nuclear Power Plant will be decommissioned. The plant operators had previously stated that reactors 1 to 4 would never operate again.


Nuclear accidents
In terms of consequences of radiation release, worker exposure, and core damage the Fukushima I nuclear accidents in 2011 were the worst experienced by the industry in addition to ranking among the worst civilian nuclear accidents. The Tokaimura reprocessing plant fire in 1999 has 2 worker deaths, one more exposed to radiation levels above legal limits and over 660 others received detectable radiation doses but below permissible levels. The Mihama Nuclear Power Plant experienced a steam explosion in one of the turbine buildings in 2004 where 4 workers were killed and seven others injured.

2011 accidents
A map showing epicenter of earthquake and position of nuclear power plantsMain article: 2011 Japanese nuclear accidents
There have been many nuclear shutdowns, failures, and partial meltdowns which were triggered by the 2011 Tōhoku earthquake and tsunami.

Plant description Accident descriptions
Fukushima I Nuclear Power Plant Fukushima I nuclear accidents
Timeline of the Fukushima nuclear accidents

Fukushima II Nuclear Power Plant Fukushima II nuclear accidents
Onagawa Nuclear Power Plant Onagawa Nuclear Power Plant incidents
Tōkai Nuclear Power Plant Tōkai Nuclear Power Plant incidents
Rokkasho Reprocessing Plant Rokkasho Reprocessing Plant incidents

Fukushima 1 accidentsAccording to the Federation of Electric Power Companies of Japan, "by April 27 approximately 55 percent of the fuel in reactor unit 1 had melted, along with 35 percent of the fuel in unit 2, and 30 percent of the fuel in unit 3; and overheated spent fuels in the storage pools of units 3 and 4 probably were also damaged". The accident has surpassed the 1979 Three Mile Island accident in seriousness, and is comparable to the 1986 Chernobyl disaster.The Economist reports that the Fukushima disaster is "a bit like three Three Mile Islands in a row, with added damage in the spent-fuel stores", and that there will be ongoing impacts:

Years of clean-up will drag into decades.
A permanent exclusion zone could end up stretching beyond the plant’s perimeter. Seriously exposed workers may be at increased risk of cancers for the rest of their lives...

On March 24, 2011, Japanese officials announced that "radioactive iodine-131 exceeding safety limits for infants had been detected at 18 water-purification plants in Tokyo and five other prefectures". Officials said also that the fallout from the Dai-ichi plant is "hindering search efforts for victims from the March 11 earthquake and tsunami".

Other accidentsMain article: Nuclear accidents by country
See also: Lists of nuclear disasters and radioactive incidents
Other accidents of note include:

1981: almost 300 workers were exposed to excessive levels of radiation after a fuel rod ruptured during repairs at the Tsuruga Nuclear Power Plant.
December 1995: the fast breeder Monju Nuclear Power Plant sodium leak. State-run operator Donen was found to have concealed videotape footage that showed extensive damage to the reactor.
March 1997: the Tokaimura nuclear reprocessing plant fire and explosion, northeast of Tokyo. 37 workers were exposed to low doses of radiation. Donen later acknowledged it had initially suppressed information about the fire.
1999: a fuel loading system malfunctioned at a nuclear plant in the Fukui Prefecture and set off an uncontrolled nuclear reaction and explosion.
September 1999: the criticality accident at the Tokai fuel fabrication facility. Hundreds of people were exposed to radiation, three workers received doses above legal limits of whom two later died.
2000: Three Tokyo Electric Power Co. executives were forced to quit after the company in 1989 ordered an employee to edit out footage showing cracks in nuclear plant steam pipes in video being submitted to regulators.
August 2002: a widespread falsification scandal starting in that led to the shut down of all Tokyo Electric Power Company’s 17 nuclear reactors; Tokyo Electric's officials had falsified inspection records and attempted to hide cracks in reactor vessel shrouds in 13 of its 17 units.
2002: Two workers were exposed to a small amount of radiation and suffered minor burns during a fire at Onagawa Nuclear Power Station in northern Japan.
9 August 2004: four workers were killed after a steam explosion at the Mihama-3 station; the subsequent investigation revealed a serious lack in systematic inspection in Japanese nuclear plants, which led to a massive inspection program.
2006: A small amount of radioactive steam was released at the Fukushima Dai-ichi plant and it escaped the compound.
16 July 2007: a severe earthquake (measuring 6.8 on the Richter scale) hit the region where Tokyo Electric's Kashiwazaki-Kariwa Nuclear Power Plant is located and radioactive water spilled into the Sea of Japan; as of March 2009, all of the reactors remain shut down for damage verification and repairs; the plant with seven units was the largest single nuclear power station in the world.