Is it Sayonara for Kashiwazaki?

9 September 2007 (Last Updated June 5th, 2020 12:25)

An earthquake in July 2007 caused the world's biggest nuclear power station to leak radioactive waste into the sea. Paul French investigates what went wrong, what went right and what the future holds for Kashiwazaki-Kariwa.

Is it Sayonara for Kashiwazaki?
In July 2007, an earthquake caused fire, spillage and destruction at the Kashiwazaki-Kariwa nuclear power station.

Plumes of black smoke are spewing out of the world’s biggest nuclear power plant. Flames are licking the walls of one of the electrical transformers. And, away from the naked eye, barrels containing nuclear waste are toppling over and radioactive water is sloshing into the sea.

For the residents of Japan’s Niigata Prefecture and exponents of nuclear power everywhere, it is a nightmare come true: an earthquake has caused fire, spillage and destruction at the Kashiwazaki-Kariwa nuclear power station.

In the immediate aftermath of the disaster in July 2007, Kashiwazaki-Kariwa’s owners, The Tokyo Electric Power Company (TEPCO), wanted to reopen the plant the next day. They were prevented from doing so by the trade ministry, and in the days that followed Kashiwazaki-Kariwa was denigrated by the world’s media amid accusations of cover-ups, poor management and insufficient safety standards.

The plant is currently closed pending investigations and will not be opened again until its safe operation can be guaranteed. Whilst the gates of the world’s biggest power station remain locked, questions are being asked about what really happened at Kashiwazaki-Kariwa.

“Kashiwazaki-Kariwa is the largest nuclear power station in the world.”

How could a nuclear plant built in a country so prone to earthquakes not withstand a quake measuring 6.8 on the Richter scale? How bad, really, were the radioactive leaks? And will Kashiwazaki-Kariwa ever open its doors again?


Residents in Kashiwazaki and Kariwa, a coastal city and town in the Niigata Prefecture that lie approximately 135 miles northwest of Tokyo, have been uneasy about having a nuclear power station on their doorstep since the plan was first announced back in 1969.

Local anti-nuclear activist Takemoto Kazuyuki first campaigned against the station in 1974. By the mid-80s, when the plant opened, petitions, demonstrations and court cases had become a way of life in this previously peaceful corner of Niigata.

“Media outlets and bloggers came down hard on Kashiwazaki-Kariwa following news of the leaks.”

These days, however, most locals have given up the fight, greeting questions about the station with a wary ‘shikata-ga-nai’, meaning ‘it can’t be helped’.


So what changed their minds? Perhaps it was the fact that Japan, as a country prone to earthquakes, purports to take earthquake prevention very seriously. There are strict rules on building anything in Japan, whether it’s a small condo or a nuclear power station, and the guidelines on the earthquake resistance of nuclear facilities in Japan were revised and tightened up in 2006 by the Nuclear Safety Commission of Japan.

Perhaps it was the $150 ‘reactor money’ everyone within a 50km radius of Kashiwazaki-Kariwa receives to compensate for the ‘inherent danger’ of living so close to a nuclear reactor.

Or perhaps it was just because they thought the plant was quakeproof. In October 2004 an earthquake measuring 6.9 on the Richter scale struck the Niigata Prefecture, killing 40 people and damaging 6,000 homes, but causing practically no damage to the power station.

Whatever their reasoning; the fact remains that on Monday 17 July 2007, the darkest fears of the residents of Kashiwazaki and Kariwa came to life when an earthquake struck the power plant causing radioactive leaks and fires.

“There are strict rules on building anything in Japan, whether it’s a small condo or a nuclear power station.”


At 10.13am an earthquake, centred approximately 250km northwest of Tokyo, struck Niigata Prefecture. Eleven people were killed, 1,000 were injured and 35,000 lost their water supply.

At the Kashiwazaki-Kariwa power plant, three of the seven reactors were operational. They all shut down safely as the tremors began, although a fire erupted in the transformer of one of the reactors. A fourth reactor was in the process of starting operation but its systems shut down automatically.

Of the three reactors that were not in use due to periodic inspections being carried out, one was affected by the earthquake. Tremors caused 1.2m³ of water to spill from a used nuclear fuel cooling pond into the sea.

The day following the quake, a government minister found radioactive iodine leaking from an exhaust pipe in one of the reactors. And during the aftershocks, 400 drums of low-level nuclear waste fell from their storage positions, with approximately 10% of them losing their lids, releasing small amounts of cobalt-60, iodine and chromium-51 into the atmosphere.


Media outlets and bloggers came down hard on Kashiwazaki-Kariwa following news of the leaks – one even called it ‘Japan’s ground zero’, with another labelling the disaster ‘worse than Three Mile Island’ (the 1979 nuclear accident at the plant with the same name which is synonymous with the worst civilian accident derived from nuclear technologies in the world). But was it really that bad?

In terms of radioactive waste into the sea and atmosphere: not really.

“Local anti-nuclear activist Takemoto Kazuyuki first campaigned against the Kashiwazaki station in 1974.”

The contaminated water that found its way into the Sea of Japan contained 90 becquerels of radioactivity, which is not seen as being enough to pose a risk to health. Spilled water inside the plant was mopped up with paper towels.

The amount of radioactivity released into the air was 402 megabecquerels, one ten-millionth of the legal limit. It is estimated that the leak caused an unintentional dose of 0.0002nSv (nanosieverts) of radioactivity per person in the affected area. The yearly limit for dosage to the public in one year in Japan is 1,110nSv.


The most incredible news to come out of the investigations into the accident at Kashiwazaki-Kariwa is that the world’s biggest nuclear power plant is built directly on top of an active earthquake fault line. The same fault line, in fact, which caused the quake on 17 July.

“Not finding the fault was a miss on our part,” says Toshiaki Sakai, who heads the engineering group in charge of Tokyo Electric’s nuclear plants. “But it was not a fatal miss by any means.”

Another major criticism of TEPCO in the wake of the quake is that they were slow to react. The fire in the transformer was allowed to burn for two hours before anyone managed to put it out. Critics claim they were also slow to inform the authorities about the problems and even when they did, their findings were inaccurate. For example, they initially said the radioactivity rating for the water that went into the sea was 60 becquerels, a figure they later revised to 90.

The July earthquake also brought into sharp focus the issue of earthquake resistance at Japan’s nuclear plants. The old guidelines ensured that nuclear plants would be built to withstand a vertical blast of 235gal. One of the reactors at Kashiwazaki-Kariwa suffered a vertical blast of 488gal.

“Kashiwazaki-Kariwa is built directly on top of an active earthquake fault line.”

Although the revised guidelines of 2006 sought to modernise things, companies were given until 2012 to carry out the relevant geological surveys and safety checks. In the wake of Kashiwazaki-Kariwa there are serious concerns about this practice. However, at a press conference on 18 July 2007, the Nuclear and Industrial Safety Agency (NISA) spokesperson, Akira Fukushima, reportedly dodged questions directed at this problem.

Finally, the accident at Kashiwazaki-Kariwa stirred up the hornets’ nest that is the viability of nuclear fuel and the question: do we really need it at all? Environmental groups point out that nuclear power is no longer necessary in a world which is capable of producing cleaner, safer renewable energy.

“Like the disaster at Chernobyl and near-disaster at Three Mile Island, today’s accident reminds us that nuclear power is hardly the safe panacea its supporters claim it to be,” said Friends of the Earth’s US executive director Norman Dean, in the immediate aftermath of the quake. “Nuclear reactors are vulnerable to natural disasters and unintentional human errors, as well as intentional sabotage such as a terrorist attack.”


The Japanese government has been stung by the criticism they received from the international community. It initially refused to allow a United Nations team in to investigate the leaks and issued a statement in which they attacked the inaccuracy of reports by the overseas media, claiming that ‘misconception has circulated’ and ‘an adverse impact has regrettably been caused on travel to our country and other areas’.

However, it later changed its mind, reportedly following a letter from the governor of Niigata Prefecture to Japanese Prime Minister Shinzo Akobe asking for UN inspections.

Whatever the reason for the turnaround, the IAEA team conducted a four-day investigation of the site in August.

“The July earthquake brought into sharp focus the issue of earthquake resistance at Japan’s nuclear plants.”

“I welcome the cooperation and transparency the team has received from the Japanese authorities,” Mohamed El Baradei, the director general of the IAEA, said following the investigation.

“The mission’s findings and the Japanese analyses of the event include important lessons learned – both positive and negative – that will be relevant to other nuclear plants worldwide.”

The IAEA report concludes that ‘plant safety features performed as required during the earthquake’, and that ‘the team’s review of plant operator records and analyses support the Japanese authorities’ conclusion that the very small amount of radioactivity released was well below the authorised limits for public health and environmental safety’.

So, the safety features did their job and the damage to the environment was limited. But, until TEPCO and the Japanese authorities can guarantee that Kahiwazaki-Kariwa is safe to re-open, the gates to the world’s biggest nuclear power plant will remain padlocked. And, as we now know it is built on top of an active fault line, they may remain so for a very long time indeed.