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Shield machine to dig undersea tunnel to discharge ‘treated water’ has not yet been approved nor has the local government… Preparations are steadily underway at TEPCO’s Fukushima Daiichi Nuclear Power Plant.

A shield machine is carried by a cart and installed at the bottom of a shaft at TEPCO’s Fukushima Daiichi Nuclear Power Plant on April 25 (courtesy of TEPCO).

April 25, 2022
 On April 25, TEPCO installed a “shield machine” at the launch site to dig an undersea tunnel to the discharge port 1 km offshore over plans to discharge contaminated water from the Fukushima Daiichi Nuclear Power Plant (Okuma and Futaba towns, Fukushima Prefecture) into the sea after purification treatment. The plan for the facilities to discharge the contaminated water has not been approved by the Nuclear Regulation Authority, and the local government has not yet given its approval for the start of construction. However, TEPCO explained at a press conference on the same day, “We are preparing for the construction work, and we will move ahead to the extent that there are no problems.

Contaminated water generated when cooling water injected into the reactors of Units 1-3 came into contact with nuclear fuel debris melted down in the accident and mixed with groundwater and rainwater that entered the buildings. Tritium, a radioactive substance that cannot be removed, remains in concentrations exceeding the national discharge standard. The government and TEPCO have been working on a plan to use large amounts of seawater to dilute the tritium concentration to less than 1/40th of the discharge standard and discharge the water into the sea.

 TEPCO began preparatory work on the 24th, bringing a shield machine (about 3 meters in diameter and 7 meters in length) to the port of the power plant, and on the 25th, placed it at the bottom of a shaft (16 meters deep) where they will begin digging an undersea tunnel built in the port area. The tunnel is now ready for construction to begin immediately. The tunnel will connect the shaft, which will temporarily store water to be discharged, with the offshore water discharge port.
 Preparations for the construction of the water discharge outlet will begin on the 25th, and excavation of the seafloor will begin on the 29th.

Although the regulatory commission has completed its review of the facility plan, TEPCO has yet to submit a revised plan to the regulatory commission based on the content of the review. The approval is expected to come after June, when the public will be invited to comment on the plan. The approval of Fukushima Prefecture and the towns of Okuma and Futaba must also be obtained before tunnel excavation can begin. (Kenta Onozawa)

May 1, 2022 Posted by | Fuk 2022 | , , , | Leave a comment

Japan’s Tepco to build underwater tunnel for Fukushima water release

December 21, 2021

The operator of Japan’s crippled Fukushima nuclear power plant intends to build an underwater tunnel to release water from the plant into the sea, it said on Tuesday (Dec 21), as part of a project to treat and dispose of contaminated water.

A decade after a massive earthquake and tsunami ravaged the north-eastern coast, disabling the plant and causing the world’s worst nuclear disaster since Chernobyl, nearly 1.3 million tonnes of contaminated water have accumulated at the site.

The water, enough to fill about 500 Olympic-sized swimming pools, is stored in huge tanks at an annual cost of about 100 billion yen (S$1.2 billion), and space is running out.

This year, Tokyo Electric Power Company (Tepco) outlined plans to discharge more than one million tonnes of the water, after treatment and dilution, from a point about 1km offshore from the power station.

Tepco submitted detailed plans on Tuesday to the nuclear regulation authority for approval, company official Junichi Matsumoto told reporters.

Pumps would move the treated water from the tanks to the seashore and through a seabed tunnel to release it at a depth of 12m, and about 1km out at sea, the firm said.

Although the international authorities support the water discharge effort, it has provoked concern from neighbours China and South Korea and worried local farmers and fisherfolk.

December 23, 2021 Posted by | Fukushima 2021 | , , , | Leave a comment

Preparations for discharging treated water into the ocean in earnest at TEPCO’s Fukushima Daiichi Nuclear Power Plant

November 26, 2021

 The Tokyo Electric Power Company (TEPCO) announced on April 26 that it will begin a survey on April 27 to construct an undersea tunnel that will connect to the outlet of the Fukushima Daiichi Nuclear Power Plant (Okuma and Futaba towns, Fukushima Prefecture), 1 km offshore, in order to proceed with a plan to release contaminated water into the sea after purification and treatment. In December, preparations began for the construction of a shaft to temporarily store the treated water, with the aim of releasing the water in the spring of 2023. In December, preparations began for the construction of a shaft to temporarily store the treated water, and the move to release the water in the spring of 2003 will be in full swing.

According to TEPCO, magnetic sensors will be used to check the seafloor at the drilling site for any obstructions in order to conduct a ground survey by boring.
 Then, over a period of about a month starting in early December, the geology will be examined by drilling 10 to 30 meters into the seabed at three points along the construction route of the undersea tunnel, about 400 meters offshore from the plant, about 700 meters, and about 1 kilometer from the discharge port.
 From early December to March next year, a 10-plus meter square hole will be dug at the site along the coast east of Unit 5, where a shaft will be installed. The timing of the construction of an undersea tunnel connecting the shaft to the discharge port has not yet been decided.
Explanations to the local community have been difficult, and there is deep-rooted opposition, especially from the fishing industry.

 The release of treated water into the ocean is strongly opposed by people in the fishing industry, and explanations to the local community by TEPCO and the government have been difficult.
 Even now, seven months after the government’s decision, TEPCO has not been able to apply for the facility plan to the Nuclear Regulation Authority. TEPCO is continuing to explain the plan to the people concerned by carrying out the seabed survey and preparatory work ahead of the plan. (Kenta Onozawa)

November 27, 2021 Posted by | Fukushima 2021 | , , | Leave a comment