Tokyo Electric Power Company Holdings Inc. and the government are considering a plan to release treated radioactive water from the crippled Fukushima No. 1 nuclear power plant into the sea about 1 kilometer from the coast, informed sources said Tuesday.
The plan calls for a pipeline to be set up at the bottom of the ocean, according to the sources.
Tepco, the government and the Nuclear Regulation Authority are expected to kick off full-fledged talks next month to decide whether to release the water directly from the coast near the power plant or offshore through a pipeline, the sources said.
The Tepco plant in Fukushima Prefecture was heavily damaged in the March 2011 earthquake and tsunami. The treated water contains tritium, a radioactive substance.
Groundwater and rainwater continue to flow into damaged reactor buildings at the nuclear power plant, ending up being contaminated with radioactive substances.
Such water is treated using special equipment and stored at tanks built at the site of the power station.
As tritium cannot be removed with existing technology, the levels of the radioactive substance will be diluted to about 1/40 of the state-set standard before the release of the treated water into the ocean.
Tepco and the government will have to make sure that seawater collected to dilute the treated water does not mix with water discharged from the plant.
The method to release the water offshore through a pipeline will be effective in preventing this from happening.
On the other hand, the technique may be costlier and require more time for preparation as it would involve steps such as conducting a drilling survey to determine whether a pipeline can be set up off the plant, the sources said.
Before the March 2011 accident, tritium-containing water from the Fukushima No. 1 plant had been released into the sea from the nearby coast. Equipment for the water release method has been kept at the plant.
Meanwhile, offshore release has been conducted for water from the Japan Atomic Energy Agency’s nuclear fuel-reprocessing plant in the village of Tokai, Ibaraki Prefecture.
Tepco and the government aim to begin releasing the treated water from the Fukushima No. 1 plant into the ocean in about two years.
They will examine the advantages and disadvantages of the two methods by analyzing past cases, the sources said.
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