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Thursday, 31 July 2014

Nuclear waste “flowing out to sea” from underground tunnels at Fukushima


Nuclear waste “flowing out to sea” from underground tunnels at Fukushima — 950 Billion Bq/m³ of cesium in Unit 2 shaft next to ocean — 11,000 tons estimated in tunnels — ‘Stream’ of moving water — Gov’t regulators ‘urgently assessing’ problems, ‘sense of crisis’ needed

July 30th, 2014

NHK, July, 30, 2014 (emphasis added): TEPCO initially planned to freeze radioactive wastewater that’s been flowing into underground utility tunnels at the plant. It hoped the measure would prevent the wastewater from mixing with groundwater and flowing out to sea. But 3 months into the project, the water hasn’t frozen as planned. [...] Utility tunnels between the No. 2 and No. 3 reactors and the sea are estimated to hold a total of 11,000 tons of radiation-contaminated wastewater.

TEPCO: Progress of blocking water at connection of trenches, July 23, 2014: Sampling results of water inside seawater piping trenches (m³ = 1,000,000 cm³)

> Unit 2 Vertical Shaft C:

Cs-134 @ 110,000-300,000 Bq/cm³
Cs-137 @ 230,000-650,000 Bq/cm³

> Unit 3 Vertical Shaft C:

Cs-134 @ 100,000-130,000 Bq/cm³
Cs-137 @ 220,000-260,000 Bq/cm³

NHK transcript, July 23, 2014: The work isn’t going as planned [...] Water used to cool melted fuel [...] has been reaching the soil [...] and seeping into the sea. Workers want to freeze the water inside the tunnels before it can leak into the ground. [...] Regulators have been skeptical [and] suggested other options such as filling the tunnels with concrete.

Asahi Shimbun, July 24, 2014: NRA instructed TEPCO to pump out contaminated water in the trenches as early as possible because water inside the underground tunnels could be leaking into the surrounding soil. […] A large volume of radioactive water […] has to be removed. […] Although the operations were scheduled to be completed at the end of May [...] TEPCO said a small stream of water in the trenches has hampered the freezing operations. […] The delay in draining the radioactive water from the tunnels could slow the construction of the frozen wall [...]

NHK, July 9, 2014: At Wednesday’s meeting of the Nuclear Regulation Authority [officials] decided to urgently assess a range of problems [and] discussed a delay in work to freeze wastewater in underground utility tunnels at the plant to block further inflows of water and stop contaminated water from leaking out to sea. Members urged that the effort be speeded up. Some expressed doubt as to whether the plant’s operator has a sense of crisis.

See Tepco’s June 1, 2011 ‘Plan to prevent water leakage containing highly concentrated radioactive materials to outside environment in Fukushima Daiichi nuclear power plant’ showing a two month ‘roadmap’ for containing the leaking tunnels (appendix 19) here.

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