Japan's nuclear watchdog is set to conduct an on-location survey at the country's only online nuclear power plant on Friday to determine whether a seam running under the Ohi plant is an active earthquake fault.
There is a 900-meter-long underground fissure between the No.2 and No.3 reactors at the Ohi plant operated by the Kansai Electric Power Company.
The Nuclear Regulation Authority (NRA) investigation team comprising one of its members, Kunihiko Shimazaki, and four other experts will visit the site, where Kansai Electric dug the ground to check the seam, and make an assessment of the fissure at a meeting on Sunday.
The Ohi plant is the first of six nuclear plants where NRA plans to conduct similar surveys. Electric companies have been examining underground seams at those plants after the March 11, 2011 nuclear disaster at the Fukushima power plant of the Tokyo Electric Power Company (TEPCO).
Construction of certain facilities of nuclear plants above active fault lines are banned in Japan. The result of Friday's survey could lead to the halt of the Ohi plant, Japanese media reported.
Kansai Electric said in its interim report on Wednesday that the seam under the Ohi plant could not be considered an active fault. But its survey is being questioned because it failed to confirm the existence of the fissure earlier.
Almost all of Japan's 50-odd nuclear reactors are remaining offline since the Fukushima accident as the country's nuclear regulator insisted thorough review of safety measures before re-starting the plants. It had also forced the Japanese government to evolve a new energy policy that seeks to do away with nuclear energy by 2030.
Meanwhile, a former worker at the Fukushima Daiichi nuclear plant filed a criminal complaint against a sub-contractor saying that the company knowingly instructed him to work in a dangerously contaminated zone in the plant.
The 46-year-old whistle-blower had worked at the tsunami-crippled plant in March and April last year.
Accompanied by his lawyer, the man told a news conference that he was instructed along with five others to lay cable in the basement of the No.3 reactor and turbine building on March 24. The radiation at the basement was extremely high at 400 millisieverts an hour, and workers employed by TEPCO had been evacuated.
But he says sub-contractor Kandenko told him to stay. He refused the order and moved to work on the first floor where he was exposed to radiation of about 11 millisieverts over an hour.
The former worker said Kandenko violated the industrial safety and health laws that protected workers, and urged the labor authorities to instruct the main contractor and plant operator TEPCO to take corrective measures so that workers at the plant could work safely.
Infrastructure giant Kandenko claims it was unaware of the high radiation level until it was informed by TEPCO after the work was done. TEPCO declined to comment on the case, saying it does not know the details of the complaint.
The whistle-blower was working for a sub-contractor of Kandenko, which in turn sub-contracts to TEPCO. Many nuclear workers in Japan are employed in such pyramid-like arrangements.
The Fukushima accident sent radioactive materials into the ocean and atmosphere, contaminated the food and water supply, and forced the evacuation of 160,000 residents in a 30-kilometer radius of the stricken plant.
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April 17, 2026 15:29 ET The ongoing conflict in the Middle East continues to raise concerns for policymakers who worry about the impact of the supply shock and high energy prices on the real economy. Producer price data and various survey results on the housing market were the main news from the U.S. this week. In Europe, industrial production data for the euro area gained attention. GDP figures out of China and the policy move by the Singapore central bank were in focus in Asia.