Status of Fukushima Daiichi
Nuclear Power Station

Apr. 25, 2014

Tokyo Electric Power Co., Inc.
0

Confirmation of cold shutdown condition
All units remain in cold shutdown condition.
Spent Fuel Pool (SFP)

Building cover

Blowout panel(closed)Reactor building (R/B)
Primary
Containment
Vessel(PCV)
ReactorPressure
Vessel(RPV)

Cover for fuel removal

構台

Transferred fuel (assemblies)
福島第一
安全第一
福島第一
福島第一安全第一
安全
第一

ｸﾛｰﾗｸﾚｰﾝ726/1533(as of 4/23)

Water
injection

Water
injection

Water
injection

Fuel debris
福島第一
安全第一

Vent pipe
Torus room
Suppression chamber(S/C )

Unit 1

Unit 2

Reactor injection water temperature:
Air temperature:

Unit 1
Unit 2
Unit 3

Unit 4

Unit 3
Unit 1

Reactor injection water temperature:
Air temperature:

Unit 2
Unit 3

Unit 3: Water injection flow rate

Unit 3: Water injection flow rate

2/4 5.5→5.0m 3/h
2/10 5.0→4.5m3/h

2/4 5.5→5.0m 3/h
2/10 5.0→4.5m3/h

RPV bottom temperatures

PCV gas phase temperatures1

Situation of Unit 1

原子炉建屋
Reactor Building（※２）温度17.0℃
SFPＳＦＰ
temperature: 17.0 ℃

Air doserate inside the Reactor Building: Max. 5,150mSv/h
原子炉建屋内雰囲気線量：
最大5,150mSv/h（１階南東エリア）（(1F southeastarea) (measured on July 24,012/7/4測定）
2012)

窒素封入流量Nitrogeninjection flow rate（※３）：28.19Nm3/h
RPV
into the RPV:28.19Nm3/h

Building cover

3/h2.3m3/h
Reactor feed給水系：2.3m
water system:
Core spray system:
2.0m33/h/h
ＣＳ系：2.0m

Temperature inside
PCV: approx. 18℃

Temperature of the RPV
ＲＰＶ底部温度：約
bottom:approx. 18℃ 18℃

ＰＣＶhydrogen concentration
Ａ系：0.01vol%
System
A: 0.01vol%
Ｂ系：0.00vol%
System B: 0.00vol%

Nitrogeninjection flow
窒素封入流量3/h 3/h（※４）
PCVinto PCV:
rate
：- Nm
- Nm

Water level of the torus room: approx.
（2013/2/20測定）
OP3,700(measured on Feb.20, 2013)

Air dose rate inside PCV:PCV 内雰囲気線量：Max. approx. 11Sv/h
最大約11Sv/hWater temperature inside
20.3℃
PCV:ＰＣＶ内水温：
approx. 20.3℃

Water level inside the PCV
2.8m
ＰＣＶ内水位：ＰＣＶ底部＋約
PCV bottom+ approx. 2.8m

Water level at the triangular corner:
三角コーナー水位：OP3,910～4,420（2012/9/20
測定）
OP3,910-4,420(measured on Sep 20, 2012)
Temperature at the triangular corner:
32.4℃-32.6℃ (measured on Sep 20, 2012)

Air dose rate inside the torus room: approx.
トーラス室雰囲気線量：
180-920 mSv/h (measured on Feb.20, 2013)

約180～

Temperature of accumulated water
insideトーラス室滞留水温度：
the torus room: approx.
20-23℃(measured on Feb.20, 2013)
約20～23℃（2013/2/20測定）

OP2,986OP2,986
タービン建屋水位：
Water levelof the Turbine Building:* Indices related to plant are values as of 11:00, April 23, 20142

Situation of Unit 2
Reactor
Building
原子炉建屋（※２）温度：15.4℃
SFPＳＦＰ
temperature: 15.4℃

Air doserate inside the Reactor Building: Max. 4,400mSv/h
原子炉建屋内雰囲気線量：（※１）表面）（2011/(1F southeast
area, upper
penetration
surface)(measured on11/16測定）
Nov. 16, 2011)
最大4,400mSv/h
（１階南側
上部ペネ

Nitrogeninjection flow rate
窒素封入流量3/h（※３）
3/hRPVthe RPV:
：15.73Nm
into
15.73Nm

Reactor feedwater system: 2.0m3/h
給水系：2.0m
3 3/hCore sprayＣＳ系：2.5m
system: 2.5m
Temperature of the RPV
bottom:approx. 28℃
ＲＰＶ底部温度：約28℃

Temperature inside
PCV:PCVapprox. 28℃
ＰＣＶ hydrogen concentration
System A: 0.05vol%
System B: 0.04vol%

Nitrogeninjection flow
窒素封入流量3/h3/h
（※４）
rate
- Nm
PCVinto PCV:：- Nm

Water level of the torus room: approx.

トーラス室水位：約OP3,270(2012/6/6
OP3,270 (measured on June 6, 2012)

Air dose rate inside PCV:
PCV
内雰囲気線量：Max.
approx.
73Sv/h
最大約73Sv/h

Air dose rate inside the torus room:
30～on April 18, 2012)
トーラス室雰囲気線量：30-118 mSv/h (measured
6～ on April 11, 2013)6-134 mSv/h (measured

Water temperature inside
ＰＣＶ内水温：約50℃
PCV:
approx. 50℃

Water level at the triangular corner:
三角コーナー水位：OP3,050～3,190（OP3,050-3,190(measuredon June 28, 2012)

Water level inside the PCV
ＰＣＶ内水位：ＰＣＶ底部＋約60ｃｍ
PCV bottom + approx. 60cm

Temperature at the triangular corner:
三角コーナー水温：30.2～32.1℃（2012/6/28 測定）
30.2℃-32.1℃ (measured on June 28, 2012)

Water level of the Turbine Building: OP2,996* Indices related to plant are values as of 11:00, April 23, 20143

Situation of Unit 3

Air dose rate inside the Reactor Building: Max. 4,780mSv/h(1F 原子炉建屋内雰囲気線量：
northeast area, in front of the equipment hatch) (measured on Nov. 27, 2012)

構台

最大4,780mSv/h

原子炉建屋

2012/11/27

Reactor Building
SFP temperature : 5.4 ℃

Nitrogeninjection flow rate
窒素封入流量3/h
intothe
RPV: 16.64Nm（※２）
RPV：16.64Nm3/h
Reactor feed water system: 2.0m3/h
3/h2.5m3/h
Core給水系：2.0m
spray system:

Temperature of the RPV
bottom: approx.
24
℃
24℃

Temperature inside
PCV: approx. 23℃
ＰＣＶ hydrogen concentration
ＰＣＶ水素濃度
System A: 0.07vol%
Ａ系：0.07vol%
System B: 0.06vol%

Nitrogen injection flow
窒素封入流量 3
rate into（※３）
PCV: - Nm3 /h
PCV：- Nm /h
福島第一

安全第一

Water level of the torus room: approx.
OP3,370 (measured on June 6, 2012)

Water level inside the PCV: unconfirmed
ＰＣＶ内水位：未確認Water level at the triangular corner: OP3,150(measuredon June 6, OP3,150（
2012)
2012/6/6 測定）
三角コーナー水位：Air dose rate inside the torus room:
100-360mSv/h (measured on100～
July 11, 2012)

Water level of the Turbine Building: OP3,002
タービン建屋水位：* Indices related to plant are values as of 11:00, April 23, 20144

Outline of Countermeasures for Decommissioning and Contaminated Water Treatment
Preparation for fuel removal and fuel debris retrieval from Units 1-3 is promoted as well as
promotion of fuel removal from spent fuel at Unit 4 are carried out.
Major work items and operation step of “Decommissioning”
Units 1 and 2

Fuel removal
fromspent fuel pool

Unit 3

Unit 4

Removal of rubble, Install fueldecontamination removal facility

Fuel removal

Storage/Transfer

Water
stoppage

Fuel debris
retrievalStorage andTransfer

Verification of
scenario/technology

Facility design

Dismantlingetc.

1- Unit 3

Fuel debris(molten fuel)retrieval

Decontamination,
leakage point
investigation

Dismantling of
nuclear facility etc.

Fuel removal from spent fuel pool
Started fuel removal from Unit 4 Spent fuel pool from
Nov. 18, 2013.
Working on the preparation work aiming at thecompletion of fuel retrieval from Unit 4 by the end of 2014.

Transferred fuel(assemblies)

726/1533( as of Apr 23)(Fuel removal )5Outline of Countermeasures for Decommissioning and Contaminated Water Treatment
Three principles and major tasks of “Countermeasures on Contaminated water issues”- Underground water flowing into the water cooled down the fuel melted in the accident. Approx. 400
tons/day of contaminated water is generated, and stored in the tanks within the site.

(1) Purification of contaminated water bymulti-nuclide removal equipment.

(1) multi-nuclide
removal equipment
Planned site
for tank installation(8) Seaside
impermeable wall(2) Removing contaminated water in the trench.

Policy 2. Keeping water away from the contamination

Tank installed
area(3) Pumping ground water through a groundwater bypass(4) Pumping ground water from the well near the building.
(5) Installation of land impermeable barrier by thefrozen soil method.

(7) Underground soil improvement by liquid glass(8) Installation of impermeable barriers in the sea(9) Installation of additional tanks(e.g. Replace with welded joint tanks.)(6) Paving for water
ingress prevention(3) Groundwater bypass(4) Sub-drain(5) Sea side
impermeable barriers(6) Pave the ground surface to prevent the ingress of rainwater.

Policy 3. Avoiding leakage of the contaminated water

Groundwater flow

Policy 1. Eliminating the source of the contamination(8) Seaside
impermeable barriers(2) Elimination ofhigh-concentration
contaminated water inthe trenches.

(7) Undergroundsoil improvement

6

Status of Countermeasures for Decommissioning and Contaminated Water Treatment in the past one month(1) Started operation of pumping through a groundwater bypass
Activated each pump of 12 groundwater bypass
pumping wells sequentially from Apr. 9, and started
pumping up the groundwater.
Groundwater which was pumped up is stored in thetank and water quality test by the third party is
ongoing.

Pumping well (sealing structure)(2) Started removal of fuel exchanger at Unit 3 fuel exchangers
Started removal of rubble in Spent fuel pool from last Dec.
Removal of fuel exchangers was started on Apr. 19 earlier than expected due to the acceleration ofremoval of rebar, roof material, and concrete piece.
Fuel exchanger

Fuel exchanger

Mast

Removed fuel exchangers mast (3.27.2014)

curing material
Completed layout of fuel rack curing
material/Started removal of fuel exchangers 7

Status of Countermeasures for Decommissioning and Contaminated Water Treatment in the past one month(3) Wrong transfer of accumulated water to incineration workshop building Since Four temporary pumps, which is normally not used (Process main building →Site banker building: One unit, process main building →Incineration workshop building: One unit, Incineration workshop
building→Process main building : Two units) was operated, accumulated water was transferred from process
main building to the incineration workshop building, which is supposed not to store it.
 Now accumulated water in the incineration workshop building is being transferred to the process main building(Apr. 14- ). As countermeasures for management, security of power panel, control of valve, and locking ofbuilding/door are enhanced.

From
Turbine building

Incineration
workshop building
Normal transfer

Process mainbuilding

Site banker building

Building not normally used asstorage for accumulated waterWrong transfer

Layout of transfer route8

Status of Countermeasures for Decommissioning and Contaminated Water Treatment in the past one month(4) Validation of freezing of small-scale impermeable barriersA feasibility study has been conducted toward the installation of frozen impermeable barriers surrounding
Units 1 to 4.
Freezing test for small-scale impermeable barriers, about 10m x 10m on the west side of the common
pool began on Mar. 14.
Small-scale impermeable barriers were confirmed to be developed by the temperature / groundwaterlevel check, and confirmation by turning over the soil .

Groundwater level control test(6) (5)(1) (2) (3) (4)Small-scale freezing test for impermeable barriers

Coolant circulation pipe

Cooling duct installed barriers

9Status of Countermeasures for Decommissioning and Contaminated Water Treatment in the past one month(5) Design plan for additional storage tank of accumulated water
Accelerated to execute the plan from 2015 to 2014, to increase the number of tanks up to about 800000
m3 by transferring tank manufactured in the factory by the ship, in addition to the tank to be constructedon site.

Tank transported by the ship
Unloading tank(6) Fukushima Advisory Board for the countermeasures for Decommissioning and Contaminated Water Treatment
Second meeting was held on Apr. 14 (Iwaki-city) . Based on the opinions from last time(Feb. 17),
information on the current project was shared. We received suggestions from the attendees for further
improvement for timely information sharing .

(7) Established Fukushima Daiichi Decommissioning Promotion Company
Launched “Fukushima Daiichi Decommissioning Promotion Company” on Apr. 1 for the purpose of theclarification of responsibility structure of countermeasures for Decommissioning and Contaminated Water
Treatment for Fukushima Daiichi Nuclear Power Station and focusing on the project .

10

Progress of Fuel Debris Retrieval in the past one month(1) Demonstration of decontamination equipment in the buildingTo establish decontamination plan for reactor building in preparation of future debris retrieval , conducteddemonstration of decontamination equipment, and developed for the subsidized project by METI.
・Suction/blast decontamination equipment: 1/30-2/4 First floor at Unit 1 Reactor building
・Dry ice blast decontamination equipment: 4/15- 21 First floor at Unit 2 Reactor building
・High-pressure water decontamination equipment : 4/23- 29 First floor at Unit 1 Reactor building

Suction/blast
decontamination equipment

Decontamination equipment fordry ice blast

Decontamination equipment for
high-pressure water11

Progress of Fuel Debris Retrieval in the past one month(2) Boring on the floor in preparation of investigation for outer bottom
section of Suppression chamber of Unit 2
 In order to confirm the applicability of investigation equipment for outer bottom section, which is developed insubsidized project by METI, actual device verification for Unit 2 was planned during the month of July-Aug.
Boring process will be conducted in advance to prevent interference with other work. (4/17-26)

Bird'seye view camera
調査装置追跡俯瞰forinvestigation system
tracking（気中・水中両用）(Borehole for both
カメラ投下穴in-air/underwater)（φ250mm)Borehole for
調査装置投下穴
investigation
system（φ350mm)Borehole(気中)for全体俯瞰
Bird's eye view camera(in-air)
カメラ投下穴（φ250mm)

Magnet wheel (Four-wheel)
Front and rear camera
Side camera(left /right)

Investigationequipment

Borehole location on the 1st floorof reactor building at Unit 2
Image of actual device
verification

Marker mechanism

Investigation equipment for
S/C outer bottom section

12

Status of Fuel Debris Retrieval in the past one month(3) First floor of reactor building for Unit 3
Investigation of water flow from main steam isolation valve room
 Water flow was confirmed to be flown from around the door of the main steam isolation valve room located in the northeast areaof 1st floor of reactor building into adjacent floor drain funnel (outlet) on Jan. 18. The outlet is connected to the basement stairsof reactor building, and it will not be leaked outside the building.
 Based on the results of temperature of water flow and radioactive material , drawings etc., accumulated water is expected toexist in the PCV.
 From Apr. 23, started to conduct image acquisition by the camera and dose measurement for the piping for instrument thatconnected air conditioning machine room on the 2nd floor of reactor building and main steam isolation valve room of 1st floor.
Dosimeter(hotspot dosimeter)
Air conditioning
machine room on the
2nd floor of RB

Floor drain
funnelWater flow

North

(PCV side)

Water flow

MSIV roomon the 1st floor ofreactor building

Bird's eye view camera for investigation(panning tilt camera )Endoscope camera for investigation
Radiation monitor
for main steam piping
process

Feed water line

Grating

Floor drain
funnelOutline of water flow condition

main steam isolation valve room

Main steam
piping

MSIV room on the1st floor of reactor
building (cross section)

13

(Reference) Status of Fuel debris retrieval(1) Investigation around lower part of vent pipe at Unit 1(Outline)In preparation of PCV repair (water stoppage) required for fuel debris retrieval, conductedinvestigation around the lower part of vent pipe to estimate point of leakage from PCV.
Leakage from the vent pipes and the sand cushion drain pipes, and the external conditions of thesepipes were checked using images captured by cameras mounted on a surface boat.
PCV

Vacuum break line

S/C
Vent pipe
A

B
C

Sand
cushionD

Point A : Vent pipe sleeve
Point B : Vent pipe
Point C : Sand cushion drain pipe
Point D : Sand cushion ring header

Sandcushion
ドレンライン
Drain funnel

Surface boat

Suppression Chamber (S/C )Surface boat: Travel test at factory14

(Reference) Status of Fuel debris retrieval(1) Investigation around lower part of vent pipe at Unit 1 (investigation results)
Investigation results of suction drain pipe
Water was confirmed to be flown downward on the surface of S/C from the direction of upper part of
the S/C of vent pipe [4].
No leakage was found between [1]- [3] and [5]- [8].
Left side of the ventpipe at [4] (whenfacing toward S/C)
N

X-5B

(3)

X-5C

X-5A

X-5D

X-5H

X-5E
X-5G X-5F(6)

Right side of the ventpipe at [4] (whenfacing toward S/C)

Side surface of S/CSide surface of S/C(4)Side surface of S/C(7)

Vent pipe

(2)

(1)
(5)

Vent pipe

Side surface of S/C(8)Water surface in thetorus room

Water surface in thetorus room

15

(Reference) Status of Fuel debris retrieval(1) Investigation around lower part of vent pipe at Unit 1 (investigation results)
Investigation results on the sand cushion drain pipes- Damage and leakage were found on the sand cushion drain pipe at [1].
- Drain pipe was not damaged and there was no water flow between [2] and [8].
- The sand cushion ring header was found to have been damaged between [1] and [2].

SR 弁
ベン
スリ ト管
ーブ

排気
管

(2)

(1)

真空破壊ライン(3)

Sand cushion
drain pipe

Ｓ／Ｃ

サンドクッシ
ョン
ドレン管

(5)

Sand cushion drain pipe at (1)

(4)
(6)

(7)

(8)

Leakage spot on the sandcushion drain pipe
Spot that has broken off inthe sand cushion ring header

Sand cushion
ring header

Breaking off between [1] and [2]To the floor funnel

16

(Reference) Status of Fuel debris retrieval(2)Measuring inside the S/C at the Units 2(Outline) Conducted measurement for water level inside the S/C (Suppression chamber) for the purpose of estimating opening
status of point leaking from PCV in preparation of PCV repair (water stoppage) required for fuel debris retrieval.
(Estimating aperture area at leakage point by the difference of water level inside and outside the S/C (Torus room), andverifying possibility of releasing of water stopping material that fills the S/C from inside the S/C etc.)
 Demonstration of technology to measure water level inside the S/C of reactor building at Unit 2 by ultrasonic wave fromouter surface of S/C on Sep. 2013 by using remote control developed for Agency for Natural Resources and Energy
FY2012 Structural improvement project for technology related to the measurement on the power reactor accident.
(development of base technology for remote control for water level measurement inside the cylindrical container). Since
S/C surface condition was worse than expected, water level could not be detected instead of confirming the water phase.
Based on the experience and the result of mock-up test at plant and Unit 4, water level measurement was confirmed tobe capable of being conducted, and resumed demonstration at Unit 2.
External
surface of S/CTorus room

Monitoring device

S/C

Measuring device

Measuring device
TravelingSurface of accumulatingwater in Torus Room

Image of Measurement inside the S/C at the Units
2

Measurement
17

(Reference) Status of Fuel debris retrieval(2) Measuring inside the S/C at the Units 2(Measurement results)
The measuring was conducted from January 14 to 16 at multiple lines (multiple longitudes) in order toenhance the reliability of specifying the exact water level. The numerical values of January 14 and 15 in
the following chart were obtained in the middle of the series of the data collecting work.
Measurement date

January 14

January 15

January 16

Water level in S/Cabout OP3,210

about OP3,160

about OP3,150

Water level of accumulating water
inside Torus Room (Reference)about OP3,230

about OP3,190

about OP3,160

Water level difference

about 20ｍｍ

about 30ｍｍ

about 10ｍｍ

Measuring method

Direct distance measuring for structures the in the water[Note] It is estimated that the water level inside the S/C is influenced by the change of the water level of accumulating water inside the torus room.
S/C diameter: 8900ｍｍ

First floor level of the Unit 2
Reactor Building: OP 10,200 mm

S/C

S/C equator : OP 1,900 mm

During of the water level measuring

First basement floor of the Unit 2
Reactor Building (Lowest level): OP-3
3,360 mm

18

(Reference) Status of Fuel debris retrieval(2)Measuring inside the S/C at the Units 2 (Future effort)
Element test of water stoppage
method for vent pipe as a national
project is on-going.

Vacuum break valve
D/W
Vent pipe

Water stopping
material

S/C

Stopping watersupport material×Since cooling water in the D/W will
be flowing into S/C via piping inside
the vent pipe when increasing waterlevel inside the D/W, verification on
the filling inside the S/C with water
stopping material will be conducted(also isolate S/C connector).

×
Exhaust pipe of main
steam safety relief valve

S/C connector

Water stoppage method

Investigate on lower surface of S/C
to check possibility of releasing ofwater stopping material that fills the
S/C Torus room.
19