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Current Status of Each Countermeasure for Contaminated Water

September 8-10th, 2014Yoshitaka HAGIWARA

Fukushima Daiichi Decontamination and DecommissioningEngineering Company, TEPCO


Contents1. Current groundwater conditions

2. Contaminated water storage

3. Measures against contaminated water

4. Operation of groundwater bypass

5. Construction of seaside impermeable wall

6. Restoration of sub-drains

7. Construction of frozen soil wall

8. Seawater piping trench

9. Water stop of connection between trench and building

10. Facing

11. Radionuclide concentration of water

12. Video about Frozen soil wall


1. Current groundwater conditions

1号機 2号機 3号機 4号機

地下水

地下水

(c) GeoEye/Japan Space Imaging CorporationCurrent flow of groundwater

Unit 1

Unit 1 Unit 2 Unit 3 Unit 4

groundwater

groundwater

The water level of the contaminated water inside the buildings is kept lower than that of the outer groundwater, which prevents water inside from flowing out. Therefore, contaminated water in the buildings does not mix with the groundwater flowing around the buildings. However, the difference of water level raises the inflow of groundwater into buildings.

The water level of the contaminated water inside the buildings is kept lower than that of the outer groundwater, which prevents water inside from flowing out. Therefore, contaminated water in the buildings does not mix with the groundwater flowing around the buildings. However, the difference of water level raises the inflow of groundwater into buildings.


2-1. Circulating water and reactor cooling

④Water storage (approx.400m3/day)

TanksTanks

Desalination

Turbinebuilding

Reactor building

Groundwater

Cooling water tank

ALPS(Advanced Liquid

Processing System)

Cs removal

②Groundwater inflow(approx. 400m3/day)

①Reactor cooling water (approx.300m3/day)

Contaminated water

Treated water contaminated water)

③Treatment(approx. 700m3/day)


Steel horizontal tank

Flange type steel cylindrical tank

Steel square type tank

Welded type steel cylindrical tank

*As of June 17, 2014

【Amount of contaminated water stored in tanks＊】

Fresh water： approx. 21,000m3

Waste water generated by evaporative concentration：approx. 9,000m3

Concentrated salt water at RO device：

approx. 367,000m3

Water treated by ALPS： approx. 128,000m3

Total amount of 525,000m3 * is stored in tanks. Current available storage capacity* is 570,000m3. Available storage capacity will be increased up to 800,000m3. (by the end of March 2015 )

Total amount of 525,000m3 * is stored in tanks. Current available storage capacity* is 570,000m3. Available storage capacity will be increased up to 800,000m3. (by the end of March 2015 )

2-2. Contaminated water storage


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2013/8/27

2013/9/24

2013/10/22

2013/11/19

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2014/1/14

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0

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建屋内滞留水貯蔵量（①）

廃液供給タンク、SPT(B)（②）

処理水タンク貯蔵量（④）

貯蔵量増加量（①＋②＋④）

その他移送量除く貯蔵量増加量（①＋②＋④－※）

浪江降水量＊

滞留水貯蔵量

平均の日増加量／浪

万m3

m3/日mm/週

Water in buildings (a)Water in buffer tanks (b)Water in storage tanks (c)Increased volume of stored waterIncreased volume excluding artificial inflowRainfall

olum

e (1

0 th

ouda

nd m

3 )

m3 /d

ay),

rainfa

ll (m

m/w

eek)

2-3. Stored water volumeS

tore

d w

ater

vol

ume

(thou

sand

m3 )

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700

Incr

ease

rate

(m3 /d

ay),

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nfal

l (m

m/w

eek)



Urgent① Ground improvement/pumping groundwater/ facing

Fundamental a)Seaside impermeable wall

Fundamental c) Sub-drain

Urgent② Removing contaminatedwater from trench

-Stopping flow to the port ① Ground improvement/pumping groundwater/paving at contaminated area<Leakage prevention> <Contaminant isolation>

-Elimination of pollution source ② Removing contaminated water from trench <Contaminant removal>-Suppression of contaminated water increase ③ Pumping up groundwater from hillside（groundwater bypass） <Contaminant isolation>

-Stopping flow to the port ① Ground improvement/pumping groundwater/paving at contaminated area<Leakage prevention> <Contaminant isolation>

-Elimination of pollution source ② Removing contaminated water from trench <Contaminant removal>-Suppression of contaminated water increase ③ Pumping up groundwater from hillside（groundwater bypass） <Contaminant isolation>

- Stopping flow to the ocean a) installing seaside impermeable wall <Leakage prevention>- Suppression of contaminated water increase/ stopping flow to the port b) installing landside frozen soil wall (“Ice wall”)

< Contaminant isolation>- Reducing groundwater flow into reactor facilities etc. c) pumping up groundwater through “Subdrain” <Contaminant isolation>

- Stopping flow to the ocean a) installing seaside impermeable wall <Leakage prevention>- Suppression of contaminated water increase/ stopping flow to the port b) installing landside frozen soil wall (“Ice wall”)

< Contaminant isolation>- Reducing groundwater flow into reactor facilities etc. c) pumping up groundwater through “Subdrain” <Contaminant isolation>

Fundamental measures

Urgent measures

3-1. Measures against contaminated water

(c) GeoEye/Japan Space Imaging CorporationUnauthorized copying and replication of the contents are strictly prohibited. All Rights Reserved. Tokyo Electric Power Company

Fundamental b) Frozen soil wall (“Ice wall”)

Urgent③ Groundwater bypass

After confirmation of pumping up, purification and discharge, due to be closed.

Construction started in June.Due to start freezing in FY2014.

Pumping up, purification and discharge of ground water planned


3-2. Emergency measures

•Emergency measure(2) Improve ground at the contaminated area with water glass, pave the ground surface with asphalt and pump up groundwater. [Isolation], [Leakage prevention]

•Emergency measure (1)Eliminate highly contaminated water in trenches. [Removal]

•Emergency measure (3)Pump up groundwater from

the mountain side (groundwater bypass)

[Isolation]

• April 9,2014, pumping up ground water at the wells was started.

•Groundwater pump up•(Groundwater bypass)

•Pump-up well•Sub drain

•Water level

•Reactor Building

•Turbine Building

•Pump-up well

•Pump-up

Improve ground and pump up groundwater Pave ground surface with asphalt to curb rainwater

infiltration

Improve ground and pump up groundwater Pave ground surface with asphalt to curb rainwater

infiltration

•Trench

•Groundwater drain pump-up

•Sea level

•Sub drain

•Pump-up

•Isolation of water from the contamination source


3-3. Fundamental measures•Fundamental Measure(4) Pump up

groundwater by sub-drains. [Isolation]

•Fundamental Measure (6) Install the frozen-soil wall to curb increase contaminated water generated by groundwater flowing into buildings. [Isolation]

•Fundamental Measure (5) Install the ocean-side impermeable walls. [Leakage prevention]

•Pump-up well

•Water level

•Pump-up•Pump-up

•Sub drain

•Groundwater drain pump-up

•Reactor Building

•Turbine Building

•Sub drain

Freezing began in March, 2015. [Supported by METI]

Freezing began in March, 2015. [Supported by METI]

•Isolating water from the contamination source

•Sea level


4-1. Operation of groundwater bypass

To reduce groundwater inflow into buildings, groundwater is pumped up at the hillside of the buildings and discharged into the ocean after conducting rigorous radioactive analysis.

It is expected that the amount of inflow into the buildings is to be reduced by tens tons of water.

After getting approval from relevant stakeholders, some groundwater have already discharged several times in batches (approx. 28,000m3 by Aug.25).

To reduce groundwater inflow into buildings, groundwater is pumped up at the hillside of the buildings and discharged into the ocean after conducting rigorous radioactive analysis.

It is expected that the amount of inflow into the buildings is to be reduced by tens tons of water.

After getting approval from relevant stakeholders, some groundwater have already discharged several times in batches (approx. 28,000m3 by Aug.25).

Overview of Groundwater bypass system

Cs134 1 Bq/L or less

Cs137 1 Bq/L or less

Gross β 5 Bq/L or less

H3 1,500 Bq/L or less

Operational Targets for Discharge


4-2. Facilities of groundwater bypass


4-3. Operation of groundwater bypass

OP9m

OP10m

Well

Well

Well

Well

Well

Pumped up volume

Rainfall

Water level of well

Water level of observation borehole (A,B)

Water level of observation borehole (C)

Rai

nfa

ll (m

m)

Wat

er

leve

l (m

)W

ater

leve

l (m

)W

ater

leve

l (m

)

Commissioning Operation Wat

er

volu

me m

3/da

y

Mar. 1 Apr. 1 May 1 Jun. 1 Jul. 1 Aug. 1


Seaside impermeable wall is to surround the sea bank of unit 1 through 4 with steel pipe. Currently landfill work between the seat pile and sea bank is underway.

Remaining opening section is planned to be closed after water purification and transfer is confirmed to work stably.

Seaside impermeable wall is to surround the sea bank of unit 1 through 4 with steel pipe. Currently landfill work between the seat pile and sea bank is underway.

Remaining opening section is planned to be closed after water purification and transfer is confirmed to work stably.

Construction the wall

Inside wall

5. Construction of seaside impermeable wall

Groundwater drain

Transfer pipe


6-1. Pumping up groundwater from groundwater drain and sub-drain systems

Groundwater levelReactor building

Turbine building

Sub-drainGroundwater bypass

Groundwater drainUpper permeable layer

Lower permeable layer

Aquiclude

Aquiclude

Seaside impermeable wall

The well placed on the seaside (groundwater drain) pumps up groundwater flowing to the sea.

Flow of groundwater will also be reduced by the upper-stream well around the buildings （sub-drain）.

Since pumping up through sub-drain greatly reduces the amount of groundwater flowing into the reactor facilities, consequently the increasing rate of highly contaminated water stored at the site will be reduced, reducing risks of ocean contamination.

The well placed on the seaside (groundwater drain) pumps up groundwater flowing to the sea.

Flow of groundwater will also be reduced by the upper-stream well around the buildings （sub-drain）.

Since pumping up through sub-drain greatly reduces the amount of groundwater flowing into the reactor facilities, consequently the increasing rate of highly contaminated water stored at the site will be reduced, reducing risks of ocean contamination.


6-2．Effect of pumping up from sub-drain

Pumping

Contaminated water accumulated

in the building

Reactor building

Water level decline

Current After operation of sub-drain

Sub-drain

Inflow of groundwater: small

Contaminated water accumulated in the

building

Reactor building

Sub-drain

Inflow of groundwater: large

Sub-drain pumping will lower groundwater level around the reactor facilities. Especially, as the difference of water levels inside and outside the buildings is 4 – 5 meters at the mountain side, it is estimated to be able to reduce water amount of 200m3/day by the operation of the sub-drain system. Therefore, reducing groundwater inflow will consequently lead to reducing the increasing rate of contaminated water stored at the site.

Sub-drain pumping will lower groundwater level around the reactor facilities. Especially, as the difference of water levels inside and outside the buildings is 4 – 5 meters at the mountain side, it is estimated to be able to reduce water amount of 200m3/day by the operation of the sub-drain system. Therefore, reducing groundwater inflow will consequently lead to reducing the increasing rate of contaminated water stored at the site.


6-3. Discharge of purified groundwater


Purification

Discharge to port

Pumping-up（Subdrain）

Water collecting

tank

Temporary storage tank

Pumping-up（Groundwater drain）

The purified groundwater will be discharged to inside of port after confirming it meets the water quality standards (management objective) set by groundwater bypass.

Discharge will not be carried out without the understanding of such stakeholders as the relevant ministries and the fishermen.

The purified groundwater will be discharged to inside of port after confirming it meets the water quality standards (management objective) set by groundwater bypass.

Discharge will not be carried out without the understanding of such stakeholders as the relevant ministries and the fishermen.


7-1. Frozen soil wall The walls surround the buildings with frozen soil and reduce groundwater inflow into them. Test at the site was conducted, and the formation of expected ice wall was confirmed. Freezing pipes are being installed and it is aimed at starting freezing the soil by next March.

The walls surround the buildings with frozen soil and reduce groundwater inflow into them. Test at the site was conducted, and the formation of expected ice wall was confirmed. Freezing pipes are being installed and it is aimed at starting freezing the soil by next March.

Freezing plant

-Total length; 1,500m-Amount of soil to be froze; 70,000m3

Ice wall

Ice wall (30 m deep)permeableimpermeable

Overview and cross-section of ice wall

① ② ③ ④⑤⑥

Japan Space Imaging Inc., (C)DigitalGlobeSmall scale test

test for ground water controlIce wall

Coolant circulation pipes

Wells for freezing pipes

（Frozen soil）

Chunk of frozen soil

Ground-water level T/BR/B

Feasibility study


7-2. Groundwater flow after installation of frozen soil wall

Seaside impermeable wall

Frozen soil wall (“Ice wall”)

As a fundamental measure, we are constructing the frozen soil wall around Units 1 to 4, as well as pumping groundwater through sub-drain and closing the impermeable wall. The construction started in June, 2014, and freezing is scheduled to start by next March.

The “Frozen soil wall” will prevent groundwater from flowing into the buildings, instead making it flow around the Units 1 to 4 buildings and lead to the sea.

Since flow of underground water around Units 1 to 4 will be greatly reduced if the “Frozen soil wall” operates, the amount of water pumped up by sub-drain will also be greatly reduced.

Amount of water pumped up through groundwater drain will also be reduced since flow of groundwater to the seaside impermeable wall will be greatly reduced after the start of “Frozen soil wall” operation.

As a fundamental measure, we are constructing the frozen soil wall around Units 1 to 4, as well as pumping groundwater through sub-drain and closing the impermeable wall. The construction started in June, 2014, and freezing is scheduled to start by next March.

The “Frozen soil wall” will prevent groundwater from flowing into the buildings, instead making it flow around the Units 1 to 4 buildings and lead to the sea.

Since flow of underground water around Units 1 to 4 will be greatly reduced if the “Frozen soil wall” operates, the amount of water pumped up by sub-drain will also be greatly reduced.

Amount of water pumped up through groundwater drain will also be reduced since flow of groundwater to the seaside impermeable wall will be greatly reduced after the start of “Frozen soil wall” operation.


8-1. Removing contaminated water from the Seawater Piping Trench

Unit 2 seawater piping trench

Unit 3 seawater piping trench

Shaft A

Shaft B Shaft C

Shaft D

Tunnel B

Tunnel A

Open‐cut duct

Shaft A

Shaft B Shaft C

Shaft D

Ｎ

Unit 2 turbine building Unit 3 turbine building

Blocked

Seawater piping trench of Unit 2 and 3 contains highly contaminated water which came from turbine buildings just after the accident.

To prevent from leaking to ocean, this contaminated water will be removed from the trench.

Seawater piping trench of Unit 2 and 3 contains highly contaminated water which came from turbine buildings just after the accident.

To prevent from leaking to ocean, this contaminated water will be removed from the trench.

: Planned freezing areas

Volume of water in Trench (m3)

Unit 2 5,000Unit 3 6,000


Freezing the connection to the turbine building

Transfer of contaminated water inside the trench

Injection of coolant in the trench and shafts

Unfreezing the connection to the building and injecting coolant

１

２

３

４

O .P .+1 0 m

１

２３

３２

４

配管

立坑

立坑

トンネル

ケーブルトレイ

P

タービ

ン建屋

滞留水水位O .P .約+3 m

O .P .+7 .4 m

：充填範囲

8-2. Removing contaminated water from the Seawater Piping Trench

【Steps involved in the measure for removing contaminated water from seawater piping

trenches】

O.P. +3.8m

O.P. -0.6m

Connection

O.P. -12.0m

O.P. 2.7-3.1m

Seawater piping trench cross section

O.P. +10.0m

Approx. 70m

: Scope of coolant injection

Turbine bu

ilding

Shaft Cable tray

Level of remaining water

Shaft

TunnelDuct

The connections between the turbine building and seawater piping trenches are separated by a wall, but ducts, etc. penetrate the wall and the remaining water is able to travel between the turbine building and seawater piping trenches.

To remove the contaminated water, the feasibility of creating an ice wall is being examined as a means to separate the turbine building from the seawater piping trenches and thereby stop the flow of water.

The connections between the turbine building and seawater piping trenches are separated by a wall, but ducts, etc. penetrate the wall and the remaining water is able to travel between the turbine building and seawater piping trenches.

To remove the contaminated water, the feasibility of creating an ice wall is being examined as a means to separate the turbine building from the seawater piping trenches and thereby stop the flow of water.


To be surveyed

Tons of Inflow from the connected duct to HTI (High Temperature Incinerator) building was identified and water stop work was completed this March.

Under construction

No inflow:

Water stop completed

9. Water stop of connection between trench and building

Accumulated water

TrenchBuilding wall

Bedding

▽Groundwater level

▽GL

Radionuclide concentration > 103Bq/cm3



Empty

Unknown


10. Facing

建屋

降雨

フェーシングImprovement of air dose rate

Lower the groundwater level

①

②

RainfallFacing

buildings

Objectives of facing- To improve air dose rate in the site- To lower the groundwater level, consequently to reduce inflow to buildings

Objectives of facing- To improve air dose rate in the site- To lower the groundwater level, consequently to reduce inflow to buildings

complied with


5,6号機放水口北側

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I-131Cs-134Cs-137

（Bq/L）

<Reference> Notified concentrations (Concentration limits for water outside environmental monitoring area)・Cesium 137: 90 Bq/L・Cesium 134: 60 Bq/L

南放水口付近

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I-131Cs-134Cs-137

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シルトフェンス設置：4/11～4/14

11-1. Radionuclide concentration of seawater

Installation of silt fence: April 11 to April 14

Vicinity of south side of water outlet

North side of water outlets at Units 5 and 6 Front of cargo unloading wharf

Concentration of radioactive materials has been reduced up to one-100,000th to one-1,000,000th as compared to the time right after the accident.Concentration of radioactive materials has been reduced up to one-100,000th to

one-1,000,000th as compared to the time right after the accident.


11-2. Radionuclide concentration of groundwater around the buildingRecent measurement results (Bq/L)(As of June 10, 2014)

Gross beta : 36H-3: 31 Cs-134: <0.55Cs-137: 0.97

(Collected on Sep.’13)

Gross beta : <21H-3: 150Cs-134: 0.64Cs-137: 1.3


Gross beta : <21H-3:200Cs-134:<0.37Cs-137:<0.47(Collected on 9/5)

Gross beta : <21H-3: 80,000Cs-134:<0.54Cs-137:<0.52

(Collected onSep.’13)

Collection points

Upper layer

Lower layerGross beta : 5,000 H-3: 2,500Cs-134:<0.73Cs-137:0.98(Collected on Oct.’13)

Gross beta : <24 H-3:20,000Cs-134:<0.36Cs-137:0.66


Gross beta : 830H-3: 770Cs-134:<0.47Cs-137:<0.60


Gross beta : <17 H-3: 1,800Cs-134:<0.38Cs-137:<0.44

(Collected onSep.’13)

Gross beta : <18H-3: <7Cs-134:<0.46Cs-137:<0.59


Gross beta : <18 H-3:200 Cs-134:<0.38Cs-137:<0.45


Gross beta : <17H-3: 1,100Cs-134:<0.43Cs-137:<0.58


Gross beta : 8,500 H-3:12,000Cs-134:<0.67Cs-137:<0.74(Collected on Oct.’13)

1T-4

1T-5

Gross beta : <15 H-3: <110Cs-134: <0.26Cs-137: <0.23

(Collected on Apr.’14)

H25J④

1T-6

Gross beta : 13,000 H-3: 3,300Cs-134:<0.82Cs-137:<0.84

(Collected on Dec.’13)

H25J⑦

Gross beta : <17 H-3: 140Cs-134: <0.3Cs-137: <0.3

(Collected on Jun.’14)

Gross beta : <16 H-3: <110Cs-134: <0.4Cs-137: <0.5

(Collected on May,’14)

No.2-4

June 23June 23


Video about Frozen Soil Wall


For more information

Updated information regarding decommissioning is shared on TEPCO website.http://www.tepco.co.jp/en/decommision/index-e.html

current status of each countermeasure for … presentations...ice wall ice wall (30 m deep)...

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