The word "uncontaminated" in the title above is in quotation marks, because there may be radionuclides left in the groundwater to be released, particularly tritium, even though it is the water drawn from the wells placed on the west side of the reactor buildings - i.e. before the groundwater enters the reactor buildings and gets contaminated.
From Jiji Tsushin (2/3/2014), after the regular press conference by TEPCO:
地下水放出へ運用目標=トリチウム1500ベクレル未満-福島第1
Fukushima I NPP targets set for releasing groundwater into the ocean, tritium less than 1500 Bq/L
東京電力は3日、福島第1原発で汚染される前の地下水を海に放出する計画について、放射性物質の濃度を定めた運用目標を策定した。セシウム134、同137は1リットル当たり1ベクレル未満、ストロンチウム90などベータ線を出す放射性物質は同5ベクレル未満、トリチウムは同1500ベクレル未満とした。
On February 3, TEPCO announced the operating targets for densities of radioactive materials in groundwater to be relased into the ocean. The groundwater is drawn before it enters the reactor buildings and gets contaminated. The targets for cesium-134 and cesium-137 will be less than 1 Bq/L each, all-beta less than 5 Bq/L, and tritium less than 1,500 Bq/L.
放出計画は汚染水抑制策の一環。海に流せる法定の基準に比べ、運用目標は濃度を4分の1以下にした。地元漁業者に説明し、放出計画への理解を求める。
The groundwater release is part of the plan to reduce contaminated water. The densities of radioactive materials are less than 1/4 of the legal limits for release into the ocean. TEPCO will talk with the local fishermen to obtain their understanding of [consent to] the release.
基準を上回った場合は放出を中止して浄化し、基準値未満にして再開する。ベータ線を出す放射性物質は、目標よりさらに低い同1ベクレル未満になるまで浄化する方針。
If the densities are above the operating targets, the release will be suspended and the water will be purified before the release resumes. For beta nuclides, TEPCO plans to purify until the density is less than 1 Bq/L, lower than the operating target.
And here's METI (Ministry of Economy, Trade and Industry)'s effort in persuading the fishermen.
From Kyodo News (2/3/2014):
地下水バイパス稼働に理解求める 経産副大臣、全漁連に
Vice Minister of Economy asks National Federation of Fisheries Co-operative Associations for understanding of the start of groundwater bypass
経済産業省の赤羽一嘉副大臣は3日、全国漁業協同組合連合会に対し、東京電力福島第1原発の汚染水対策として、地下水をくみ上げて海に放出する地下水バイパスの稼働への理解を求めた。
Vice Minister of Economy, Trade and Industry Kazuyoshi Akaba asked National Federation of Fisheries Co-operative Associations for understanding of the start of groundwater bypass, which is part of dealing with the contaminated water at Fukushima I Nuclear Power Plant. The groundwater bypass will draw groundwater and release the water into the ocean.
経産省側は、漁業者の懸念を取り除くため、くみ上げた地下水を放出する際、放射性物質の濃度について、現行基準より厳しい運用基準を適用する考えを明らかにした。
[Vice Minister Akaba said] METI will apply the operating standards that are stricter than the existing standards in radioactive material density in the groundwater that will be drawn, in order to mitigate concerns from fishermen.
原子炉建屋に流れ込む地下水は、汚染水増加の原因となっている。地下水バイパスは汚染される前に地下水をくみ上げるが、漁業関係者を中心に、風評被害などへの懸念が強く、運用できない状況が続いている。
The groundwater that leaks into the reactor building is one of the causes for increase in contaminated water. According to the groundwater bypass scheme, the water will be drawn before it gets contaminated. However, concerns for baseless rumors remain strong particularly among fishermen, which has prevented the scheme from being implemented.
I wonder how TEPCO is going to "purify" the water to less than 1Bq/L. My guess is dilution, particularly if it is tritium which cannot be effectively removed on a large scale.
But it probably doesn't matter, as one day later Minister of Economy, Trade and Industry says METI has already obtained "a certain level of understanding" from the fisheries co-op.
From Jiji Tsushin (2/4/2014):
全漁連から一定の理解=福島第1原発の地下水対策-茂木経産相
Minister of Economy Motegi says a certain level of understanding from the fisheries co-op in dealing with the groundwater at Fukushima I NPP
茂木敏充経済産業相は4日の閣議後記者会見で、東京電力福島第1原発の汚染水対策である「地下水バイパス」計画について、全国漁業協同組合連合会(JF全漁連)から「必要性については一定の理解を得ている」との認識を示した。赤羽一嘉経産副大臣が3日、全漁連の岸宏会長に計画の概要を説明し、理解を求めていた。
In the press conference after the cabinet meeting on February 4, 2014, Minister of Economy, Trade and Industry Toshimitsu Motegi said [the ministry] has obtained "a certain level of understanding as to the necessity" of the groundwater bypass plan from the National Federation of Fisheries Co-operative Association in dealing with the contaminated water at Fukushima I Nuclear Power Plant. Vice Minister Kazuyoshi Akaba had met with Hiroshi Kishi, Chairman of the National Federation of Fisheries Co-operative Association on February 3 to explain the outline of the plan and ask for understanding.
So the National Federation of Fisheries C-op Association will bear down on the Fukushima Federation of Fisheries Co-op Association, who will then bear down on the local Fisheries Co-ops in cities like Iwaki. The local Co-Ops will bear down on individual fishermen, who will probably need little persuasion, as they are eager to resume fishing.
TEPCO/METI plan to release groundwater seems to be back on track, as if the ground contamination in the very area where the wells were dug for the groundwater drawing had never happened in August 2013.
Right near where the wells are, there are huge tanks, mostly riveted together and meant to last for no more than 5 years, that contain highly radioactive (mostly beta nuclides, not gamma) waste water after reverse osmosis (desalination) treatment. Several of the tanks in the area were found to have leaked this waste water although no one knows exactly how much waste water leaked or how it leaked, and the leak may be slowly finding its way towards the wells. The elevated levels of tritium have already been measured, although they are well below the operating target of 1500 Bq/L.
Locations of the wells for drawing groundwater for the groundwater bypass scheme, and the sample water analysis (from TEPCO, 1/30/2014): the highest contamination of tritium recorded was 1,000 Bq/L from No.12 well on 12/24/2013.
Latest measurement of contamination levels in the H4 tank area, located southeast of the wells (from TEPCO, 2/6/2014):
For more on the "RO Waste Water Leak of August 2013", click here.
Nuclear Regulation Authority is yet to approve the operating targets, so all is not yet clear for TEPCO/METI. It is muddled as ever as to who is in charge of regulating TEPCO on the Fukushima I NPP accident cleanup efforts. It is supposed to be NRA, but it is increasingly tied up with the evaluation of nuclear power plants under the new guidelines in preparation for the restart. It looks METI is there (as it has always been there) to give the plant operators like TEPCO a way out, a bypass around the regulators.