Facts Lessons FUKUGIMA

7/31/2019 Facts Lessons FUKUGIMA

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All Rights Reserved 2012The Tokyo Electric Power Company, Inc. 0

Facts and Lessons of the Fukushima NuclearAccident and Safety Improvement-The Operator Viewpoints-

February, 2012

Tokyo Electric Power Company


2/80


What I will present

1Overview of the Earthquake and Tsunami- Damages at Fukushima NPSs

-What made the difference between Fukushima Daiichi(1F) and Fukushimadaini(2F) ?

2. How we responded ?

- How the accident developed

- What difficulties existed

3. Other Relevant Items-Accident Management

-Presumption of Reactor Core State by Analysis Code

-Hydrogen Explosion

-Spent Fuel Pool

4. Current Status and Roadmap toward Decommissioning

5. Lessons Learned and Countermeasures


3/80


Overview of the Earthquake and Tsunami

Unit 6Unit 5Unit 1Unit 2

Unit 3Unit 4

Unit 1Unit 2

Unit 3Unit 4

Fukushma Daiichi(1F) Fukushma Daini(2F)


4/80


Overview of Fukushima Daiichi NPS (1F)

and Fukushima Daini NPS (2F)

Plant UnitIn

Operation

Since

Plant

Type

PowerOutput

(MWe)

Main

ContractorPre-earthquake Status

1F

1 1971.3 BWR-3 460 GE Operating

2 1974.7 BWR-4 784 GE/Toshiba Operating

3 1976.3 BWR-4 784 Toshiba Operating

4 1978.10 BWR-4 784 Hitachi

Shutdown for maintenance

Full core offloaded to spent

fuel pool

5 1978.4 BWR-4 784 Toshiba Shutdown for maintenance

6 1979.10 BWR-5 1100 GE/Toshiba Shutdown for maintenance

2F


2 1984.2 BWR-5 1100 Hitachi Operating




5/80


Seismic Intensity Distribution Hypocenter Distributionby Earthquake Research Institute, the University of Tokyo

Time: 2:46 pm on Fri, March 11, 2011.

Place: Offshore Sanriku coast (northern latitude of 38 degrees, east longitude of 142.9),24km in depth, Magnitude 9.0 Intensity: Level 7 at Kurihara in Miyagi Miyagi prefecture

Upper 6 at Naraha, Tomioka, Okuma, and Futaba in Fukushima pref.Lower 6 at Ishinomaki and Onagawa in Miyagi pref., Tokai in Ibaraki pref.Lower 5 at Kariwa in Niigata pref.Level 4 at Rokkasho, Higashidori, Mutsu and Ohma in Aomori pref., Kashiwazaki in Niigata pref.

Great East Japan Earthquake

1F

2F

epicenter

Issued at 14:53 onMarch 11, 2011

4th-largest magnitude on record in the world


6/80


Seismic Observed Data

Observation Point

(The lowest basement of

reactor buildings)

Observed dataMaximum Response Acceleration against

Basic Earthquake Ground Motion (Gal)Maximum Response

Acceleration (Gal)

Horizontal

(N-S)

Horizontal

(E-W) VerticalHorizontal

(N-S)

Horizontal

(E-W) Vertical

1F

Unit 1 460 447 258 487 489 412

Unit 2 348 550 302 441 438 420

Unit 3 322 507 231 449 441 429

Unit 4 281 319 200 447 445 422

Unit 5 311 548 256 452 452 427

Unit 6 298 444 244 445 448 415

2F

Unit 1 254 230

305 434 434 512

Unit 2 243 196 232 428 429 504

Unit 3 277 216 208 428 430 504

Unit 4 210 205 288 415 415 504

Comparison between Basic Earthquake Ground Motion and the record of intensity

: The recording time was about 130-150 seconds


7/80


Height: about 10m

Tsunami observed at 1F


8/80


Flooding in 1F

2011/3/11 15:43Date2011/3/11 15:43 2011/3/11 15:43Date2011/3/11 15:43 2011/3/11 15:44Date2011/3/11 15:44

2011/3/11 15:42 2011/3/11 15:42 2011/3/11 15:43

Date2011/3/11 15:42 Date2011/3/11 15:42 Date2011/3/11 15:43

Tank(Height:5.5m)


9/80


Damages by Tsunami at 1F

Heavy oil tank

floated

Large sizecrane moved


10/80


Sea water pumps are all damaged.

Damages by Tsunami at 1F


11/80


C)GeoEye

Inundated Areas at 1F

Inundation throughout almost all areas where main buildings sited

Units 1~4: Inundation height in areas where principal buildings sited:OP approx. 11.5m~15.5m

(Localized inundation height in southwest area: OP approx. 16m~17m)

Unit 5 & 6: Inundation height in areas where principal buildings sited: OP approx.

13m~14.5m

Almost whole area was floodedFukushima

Daiichi

Unit1

Unit2

Unit3

Unit4

Unit6

Unit5

RadwasteProcessing

building

Elevation of major

Unit-1-4 buildings:

O.P.10m

Elevation of major

Unit-5,6 buildings:

O.P.13m


12/80


O.P.+13mO.P.+13mO.P.+13mO.P.+13m

O.P.+10mO.P.+10mO.P.+10mO.P.+10m

O.P.+4mO.P.+4mO.P.+4mO.P.+4m

O.P.+4mO.P.+4mO.P.+4mO.P.+4m

3u Emergency D/Gair inlet louver

Location of Sea Water Ingression into Buildings at 1F

Turbinebuilding

Reactorbuilding

Unit 6 D/G building

Unit 5Unit 6Unit 1 Unit 2 Unit 3 Unit 4

Openings at the ground level fromwhich sea water could flow into buildings

Openings connected to undergroundtrenches/ducts where sea water could flow

into buildings


13/80


Inundated Areas at 2F

Inundation occurred throughout all areas along the sea, but it was not observed tohave inundated over the slope and into areas where major buildings are sited.

Run up of tsunami centered on the south side of Unit 1Inundation height in sea side area: OP approx. +7.0~7.5m

Inundation height in areas where principal buildings sited: OP approx. 12~14.5m

Inundation height in area south of Unit 1: OP approx. + 15~16m

Limited area was flooded

Inflowed

intensively

C)GeoEye

Unit 2 Unit 1Unit 3Unit 4

Elevation of major

Unit-1-4 buildings:

O.P.12m


14/80


[Overall view of 2F]

(1)

(2)(3)

(1)Tsunami run-up

(2)Tsunami damage in low-lying areas (shallow draft quay)

(3) No damage to the Unit 3 and 4Turbine Building

Tsunami damage at 2F

C)GeoEye


15/80


Location of Sea Water Ingression into Buildings at 2F

Inside Unit 1 heat

exchanger building

Units 3 & 4

Sea side of turbinebuilding

Openings at the ground level from which sea water could flow into buildings

Openings connected to underground trenches/ducts where sea water could flow into buildings

Heat exchangerbuilding

Turbinebuilding

Reactorbuilding

Unit

1

Unit

2

Unit

3

Unit

4


16/80


Tsunami Height 1F v.s. 2F

Base levelO.P.0m

Reactorbuilding

Ocean-sidearea Main building area

breakwater

Design basistsunami heightO.P.+5.2m

Site levelO.P. +12m

Water

intake

Safety measures has takenagainst 5.2m Tsunami heightSite levelO.P. +4m

Turbine building

2F

O.P.Onahama Peil

Hx building

Base levelO.P. 0m

--Inundation height apx. O.P. +7.0 ~ 7.5m

49

1F

Assumed highesttsunami water level

O.P. +5.7m

--

Design basis

tsunami heightO.P.+5.7m

Assumed highest

tsunami water levelO.P. +5.7m

Base levelO.P. 0m

Site levelO.P. +10m(Units 1 -4*)

* Site level on Units 5 and 6 is O.P. +13m

Turbine building

Reactor buildingInundation heightapx. O.P. +14-15m

Ocean-sidearea

Main building area

Water intake

Site levelO.P. +4m

Safety measures hastaken against 5.7m

Tsunami height

breakwater

WaterPump

Assumed highest

tsunami water levelO.P. +6.1m

Base levelO.P. 0m

Site levelO.P. +10m(Units 1 -4*)

* Site level on Units 5 and 6 is O.P. +13m

Turbine building

Reactor building-

Ocean-sidearea

Main building area

Water intake

Site levelO.P. +4m

Safety measures hastaken against 5.7m

Tsunami height

breakwater

WaterPump

Inundation height apx. O.P. +11.5 15.5m


17/80


Differences in Tsunami between 1F and 2F

1050

100150

0

24

6

8

10

12

14

[m]Sea floor

displacement[m]

Fukushima

Daiichi

Fukushima

Daini

Maximumtsunam

iheightm

Peaks coinciding

Tsunami height: High

Peaks not coinciding

Tsunami height: Low

Same amplification rate

Water level

fluctuation from

each blockTime T

Warm colored blocksgenerated massive

tsunami wave heights

Tsunami of various magnitudes at a depth ofaround 150m were amplified at the same rate

and struck at each nuclear power station

Water depth [m]

Postulated Tsunami Source Model


18/80


Permitted Design Basis(1) Tsunami assessment

Tsunami assessment in construction permit

Fukushima NPSs

Historical tsunamis of Iwate and Miyagi coast were larger than that of Fukushima

Approved design basis at Fukushima NPS was 3.1-3.7m

Fukushima NPSs

3.11.2011 tsunami heights (m)Historical tsunami heights (m)

Preliminary results by The 2011 Tohoku Earthquake Tsunami Joint SurveyGroup( http://www.coastal.jp/ttjt/) 07 May 2011

Inundation

Run-up

Unit Ground Level Tsunami Heightm

R/B,Tb/B

m

Pumps

m

Design Basis Modified in

2002 (2009)

11 march

2011

1F 1-4 10.2 4 3.1 5.7 (6.1) 14-15

1F 5-6 13.2 4 3.1

2F1-4 12 7 3.7 5.2 7-7.5


19/80


Permitted Design Basis(2) Tsunami assessment

Earthquake Magnitude Earthquake

#1 8.2 1952 Nemuro-oki

#2 8.4 1968 Tokachi-oki

#3 8.3 1896 Meiji-Sanriku

#4 8.6 1611 Keicho-Sanriku

#5 8.2 1793 Miyagi-oki

#6 7.7 1978 Miyagi-oki

#7 7.9 1938 Fukushima-oki

#8 8.1 1677 Enpo-Bousou

htt ://outreach.eri.u-tok o.ac. /e volc/201103 tohoku/#Inversion 2011/3/182011/3/11 source area

English editionhttp://www.jsce.or.jp/committee/ceofnp/Tsunami/eng/tsuna

mi_eng.html

In JSCE- 2002, assumed 8 earthquakes individually. March11 Earthquake occurred over several areas simultaneously.

Tsunami Assessment was revised based on the JSCE (Japan

Society of Civil Engineers) Method,2002


20/80


Damages of transmission line

& Shinfukushima substation by earthquake

500kV Disconnector 275kV Circuit Breaker

- About 10 km away from both 1F and 2F site

- Important switchgear station from which electricity of 1F & 2F is transmitted to Tokyo area

Transmission tower collapse

CollapseCGeoEye

Collapse of filled soil & sand

Tower collapse


21/80


4A4B

4D 4C

4E

DG

4B

DG

4A

DG

3B

DG

3ADG

2B

DG

2A

DG

1B

DG

1A

3A3B

3C3D

3SA3SB

2A2B

2C2D

2E

2SA2SB

1A1B

1C1D

1S

Shutdown by earthquake

Shutdown by Tsunami

Power supply of Unit 1-4 @ 1F after Tsunami

The DG lost the function due to either M/C failure, loss of

sea water system, or DG main unit failure.

Okuma Line 1L, 2L: Receiving circuit breaker damaged in earthquake

Okuma Line 3L: Renovation work in progressOkuma Line 4L: Circuit breaker shutdown by protection relay activation

Ohkuma

4L

Ohkuma

3L

Ohkuma

2L

Ohkuma

1L


22/80


5A

5C

5B

5D

DG

5A

DG

5B

DG

HPCS

DG

6A

DG6B

5SA-1 5SA-2 5SB-25SB-1 6A-1 6A-2

HPCS6C

6B-1 6B-2

6D

Shutdown by earthquake

Shutdown by Tsunami

Survived after Tsunami

Power supply of Unit 5/6 @ 1F after Tsunami

Futaba1L

Futaba

2L

Yonomori

2LYonomori1L

For transmittinggeneratedpower

For transmittinggeneratedpower


23/80


2F Offsite Power was secured after the Tsunami

6.9kV 6.9kV

Offsite Power

500kV66kV

H STr

Unit #1, 2 STr Unit #3, 4 STr

/

Emergency

Power for Unit #1

/

1H 1A 1B

6.9kV

/ /

2H 2A 2B

/

3H 3A 3B

6.9kV

/ /

4H 4A 4B

One 500 kV line was available.

66 kV lines were outage because of scheduled

maintenance and substation trouble but

recovered.

PPPP

Emergency

Power for Unit #2

Emergency

Power for Unit #3

Emergency

Power for Unit #4

/

P : Cooling Pumps

/ : Diesel Generator

/

P/

P/

P/

P

Tomioka Line Iwaido Line


24/80


25/80


1F Unit 1 Schematic System Diagram (After Tsunami )

Sea

TbTbTbTb

Condenser

H/WH/WH/WH/W

GenGenGenGen

CSTCSTCSTCST

FiltratedFiltratedFiltratedFiltrated

WaterWaterWaterWater

TankTankTankTank

SLC

Stack

Sea

CCSCCSCCSCCS

D/GD/GD/GD/GCCSW

SRVSRVSRVSRV

CRD

HPCIHPCIHPCIHPCI

CPCPCPCPRFPRFPRFPRFP

WWWW

CSCSCSCSMUWCMUWCMUWCMUWC

DD FPDD FPDD FPDD FP

ICICICIC

S/CS/CS/CS/Cvent valvevent valvevent valvevent valve

D/W vent valveD/W vent valveD/W vent valveD/W vent valve

RP

V

from

CSTH/W

Sea

::::Operable

::::Inoperative due

to power loss:::: Briefly

Operative


26/80


1F Unit 2 Schematic System Diagram (After Tsunami)

Sea

TbTbTbTb

Condenser

H/WH/WH/WH/W

GenGenGenGen

CSTCSTCSTCST



TankTankTankTank

SLCSLCSLCSLC

Stack

Sea

RHRRHRRHRRHR

D/GD/GD/GD/GRHRS

SRVSRVSRVSRV

CRDCRDCRDCRD

HPCIHPCIHPCIHPCI

LPCPLPCPLPCPLPCPMDMDMDMD----

RFPRFPRFPRFP

WWWW

CSCSCSCS

MUWCMUWCMUWCMUWC DD FPDD FPDD FPDD FP


D/W vent valveD/W vent valveD/W vent valveD/W vent valve

::::Operable

::::Inoperative due

to power loss

RP

V

TDTDTDTD----

RFPRFPRFPRFP

from

CSTH/W

CSTCSTCSTCST

RCICRCICRCICRCIC

HPCPHPCPHPCPHPCP

Sea

::::Inoperative


27/80


1F Unit 3 Schematic System Diagram (After Tsunami)

Sea

TbTbTbTb

Condenser

H/WH/WH/WH/W

GenGenGenGen

CSTCSTCSTCST



TankTankTankTank

SLCSLCSLCSLC

Stack

Sea

RHRRHRRHRRHR

D/GD/GD/GD/GRHRS

SRVSRVSRVSRV

CRDCRDCRDCRD

HPCIHPCIHPCIHPCI

LPCPLPCPLPCPLPCPMDMDMDMD----

RFPRFPRFPRFP

WWWW

CSCSCSCS

MUWCMUWCMUWCMUWC DD FPDD FPDD FPDD FP


D/W ventD/W ventD/W ventD/W vent

valvevalvevalvevalve

RP

V

TDTDTDTD----

RFPRFPRFPRFP

from

CSTH/W

CSTCSTCSTCST

RCICRCICRCICRCIC

HPCPHPCPHPCPHPCP

Sea

::::Operable

::::Inoperative dueto power loss

::::Inoperative


28/80


2. How we responded ?

- How the accident developed

- What difficulties existed

- What were effectively utilized


29/80


Status of 1F 1-3 immediately after the Tsunami

Fallen into the Station Black Out (SBO):All safety and non-safety systems driven by electricity were unavailable.

No lights in the control rooms, R/Bs, T/Bs, etc.

No important instrumentations for Unit 1 &2 due to loss of AC powersources and DC 125V batteries; the reactor water level/ pressure,drywell pressure, wet-well (S/C) pressure, etc. ; Operators were totallyblind!

The instrumentation of Unit 3 was available immediately after the tsunami but

only lasted for about 30hours.

Almost no communication tools between the Emergency ResponseRoom and workers at the field: only hotline and land-line phone wereavailable between the ERR and each control room.

The sea water systems were totally destroyed: no ultimate heatsink

P d b h l t t d ld h td ( tli )


30/80


1F Units 1 - 4 1F Units 5 & 6 2F Units 1 - 4

Progress made by each plant towards cold shutdown (outline)

Units 1-3 in operationUnit 4: outage in progress

[Power supply] Total loss of off-sitepower supply and DG

[Sea water system] Total loss

Water injection using IC, RCIC,

HPCI

PCV Venting, SRV operation

& Sea water injection

Switch to freshwater

Heat removal route has been

continuously improved

Currently the closed cyclecooling is in function

Sea water was initially injected intothe spent fuel pool; currentlyinjecting freshwater

Outage in progress

[Power supply] Emergency DG 6Bstart up

[Sea water system] Total loss

3/19

Alternative RHRS wasstarted and the spent fuel

pool and reactor were cooled

Water makeup by MUWC

(DG6B power used for

Units 5, 6)

3/20

Units 5, 6 cold shutdown

Installation of temporary RHRS

Installation of temporary power

supply

In operation

[Power supply] One off-site power

supply system secured

[Sea water system] Total loss apartfrom Unit 3

3/12

Unit 3 coldshutdown

Units 1, 2, 4

Water injection using MUWC

3/14 RHR startup

Water injection using RCIC

3/14 Units 1, 2 cold shutdown

3/15 Unit 4 cold shutdown

RHRC motor was replaced

Installation of temporary powersupply


31/80

All Rights Reserved 2012The Tokyo Electric Power Company, Inc.

Chronology of Accident (Fukushima Daiichi)

Unit 1 Unit 2 Unit 3 Unit 4 Unit 5-6 Common SF Pool

12thStart injecting

sea water

Start injecting

sea water

Start injecting

sea water

Switch from

seawater to

fresh waterSwitch from sea

water to fresh water

Recover Main

Control Room

lighting

Recover MainControl Room lighting

13th

14th

17th

20th21th

22th

23th

24th

25th

26th

27th

Reactor cooling

shutdown

One D/G

survived

Switched fromD/G

to offsite power

Fresh waterinjection

Received

electricity from

offsite

Start cooling by

existing system

Recover Main

Control Room lighting

Earthquake

31st

Start watering

(sea water, freshwater)

SF Pool Reactor Power Supply

Start watering

fresh water

Switch from sea


Cooling by injecting fresh water

March 11, 14:46

Switch from

seawater to

fresh water

Switch from

sea water to

fresh water

Recover Main

Control Room

lighting

Start injecting

sea water

Start watering

(sea water,

fresh water)

Switch from sea


Rx Building Explosion



15th

Suppression Chamber

Depressurization


32/80


0.000

0.200

0.400

0.600

0.800

1.000

3/11

12:00

3/11

18:00

3/12

0:00

3/12

6:00

3/12

12:00

3/12

18:00

3/13

0:00

0.53MPa abs

0.954MPa abs

0.00

2.00

4.00

6.00

8.00

10.00

3/11

12:00

3/11

18:00

3/12

0:00

3/12

6:00

3/12

12:00

3/12

18:00

3/13

0:00

7.2 8,7.35 ,7.41MPa abs

8.7MPa abs

7.0MPa abs

-3000

-1000

1000

3000

5000

3/11

12:00

3/11

18:00

3/12

0:00

3/12

6:00

3/12

12:00

3/12

18:00

3/13

0:00

)(Amm

)(Bmm

In Operation(Over Scale)In Operation(Over Scale)In Operation(Over Scale)In Operation(Over Scale)

RxWater

Level[mm]

IC

HPCI No Operation

SRV No Operation

FP/Fire Engine

PCV Vent

Fuel Range (A) (mm)

Fuel Range (B) (mm)

Rx Pressure (A) (MPa)

Rx Pressure (B) (MPa)

S/C Pressure (A) (MPa)

D/W Pressure (B) (MPa)

19:04Sea Water

Order for Vent Preparation 0:06

4:00 Fresh Water 80t 14:53

18:18 - 2521:3014:52

Earthquake

14:46

Tunami

15:27

Operation Unclear

Order for Vent 8:03 14:30 D/W Pr decrease confirmed

Unit 1 R/B

Explosion 15:36

Core Damage Started due to

MAAP Analysis

RxPressure

[MPa]

D/W&

S/C

Pressure[MPa]

1F Unit 1 Plant Parameter and Operation

0(TAF)

Rx water level data revealed incorrect afterward


33/80


-4000

-2000

0

2000

4000

6000

3/11

12:00

3/11

18:00

3/12

0:00

3/12

6:00

3/12

12:00

3/12

18:00

3/13

0:00

3/13

6:00

3/13

12:00

3/13

18:00

3/14

0:00

3/14

6:00

3/14

12:00

3/14

18:00

3/15

0:00

3/15

6:00

3/15

12:00

3/15

18:00

3/16

0:00

In Operation (Over Scal e)In O eration (Over ScaleIn O eration (Over ScaleIn Operation (Over Scale)

0.00

2.00

4.00

6.00

8.00

10.00

3/11

12:00

3/11

18:00

3/12

0:00

3/12

6:00

3/12

12:00

3/12

18:00

3/13

0:00

3/13

6:00

3/13

12:00

3/13

18:00

3/14

0:00

3/14

6:00

3/14

12:00

3/14

18:00

3/15

0:00

3/15

6:00

3/15

12:00

3/15

18:00

3/16

0:00

7.44,7.51,7.58MPa abs8.7MPa abs

7.0MPa abs

0.000

0.200

0.400

0.600

0.800

1.000

3/11

12:00

3/11

18:00

3/12

0:00

3/12

6:00

3/12

12:00

3/12

18:00

3/13

0:00

3/13

6:00

3/13

12:00

3/13

18:00

3/14

0:00

3/14

6:00

3/14

12:00

3/14

18:00

3/15

0:00

3/15

6:00

3/15

12:00

3/15

18:00

3/16

0:00

0.53 MPa abs

0.95 4MPa abs

RxWater

Level[mm]

RCIC

HPCI No Operation

SRV

FP/Fire Engine

PCV Vent

Fuel Range (A) (mm)

Fuel Range (B) (mm)



S/C Pressure (MPa)

D/W Pressure (MPa)

19:Sea Water

Order for Vent Preparation 17:30

Depressurization~18:00

Earthquake

14:46 Tunami15:27

(2:55) Operation confirmed

(11:00

Vent LineConfiguration Completed

Unit1 R/B

Explosion15:36

Core Damage Started due toMAAP Analysis

RxPressure

[MPa]

D/W&

S/C

Pressure[MPa]

1F Unit 2 Plant Parameter and OperationUnit3 R/B

Explosion11:01 Impact sound6:00-6:10

Valve Condition Unclear

Order for Sea Water InjectionPreparation 12:05

2Valves Open

Small Vent Valves Opened

(13:25)Out of Service Judged

0(TAF)


34/80


0.000

0.200

0.400

0.600

0.800

1.000

3/11

12:00

3/11

18:00

3/12

0:00

3/12

6:00

3/12

12:00

3/12

18:00

3/13

0:00

3/13

6:00

3/13

12:00

3/13

18:00

3/14

0:00

3/14

6:00

3/14

12:00

3/14

18:00

3/15

0:00

3/15

6:00

3/15

12:00

3/15

18:00

3/16

0:00

0.53MPa

0.954 MPa

0.00

2.00

4.00

6.00

8.00

10.00

3/11

12:00

3/11

18:00

3/12

0:00

3/12

6:00

3/12

12:00

3/12

18:00

3/13

0:00

3/13

6:00

3/13

12:00

3/13

18:00

3/14

0:00

3/14

6:00

3/14

12:00

3/14

18:00

3/15

0:00

3/15

6:00

3/15

12:00

3/15

18:00

3/16

0:00

7 .44MPa,7.5 1MPa,7.58MPa8.7MPa

7.0MPa

-4000

-2000

0

2000

4000

6000

3/11

12:00

3/11

18:00

3/12

0:00

3/12

6:00

3/12

12:00

3/12

18:00

3/13

0:00

3/13

6:00

3/13

12:00

3/13

18:00

3/14

0:00

3/14

6:00

3/14

12:00

3/14

18:00

3/15

0:00

3/15

6:00

3/15

12:00

3/15

18:00

3/16

0:00

In O peration(Over Scale)In O peration(Over Scale )In O peration(Over Scale)In O peration(Over Scale )

RxWater

Level[mm]

RCIC

HPCI

SRV

D/D-FP

FP/Fire Engine

PCV Vent

Fuel Range (A) (mm)

Fuel Range (B) (mm)

Fuel Range (mm)

Wide Range (mm)



S/C Pressure (MPa)

D/W Pressure (MPa)

16:30Sea WaterOrder for Vent Preparation 17:30

Earthquake

14:46 Tunami15:27

Unit1 R/B

Explosion15:36

Core Damage Started due to

MAAP Analysis

RxPressure

[MPa]

D/W&

S/C

Pressure[MPa]

1F Unit 3 Plant Parameter and OperationUnit3 R/B

Explosion11:01

Order for Preparation17:12

0(TAF)

(11:36) TripAutomatic Start(12:35)

(16:03)

(2:42) Stop

13:12Sea WaterFresh Water 9:25

(8:41 Vent Line Configuration Completed

~9:08Depressurization

(22:15) Stop due to running out of fuel

After HPCI shut down, water injectionusing D/D FP was implemented, howevernot possible due to high reactor pressure


35/80


-1000

1000

3000

5000

7000

3/11

12:00

3/11

18:00

3/12

0:00

3/12

6:00

3/12

12:00

3/12

18:00

3/13

0:00

3/13

6:00

3/13

12:00

3/13

18:00

3/14

0:00

3/14

6:00

3/14

12:00

3/14

18:00

3/15

0:00

3/15

6:00

3/15

12:00

3/15

18:00

3/16

0:00

0.00

2.00

4.00

6.00

8.00

10.00

3/11

12:00

3/11

18:00

3/12

0:00

3/12

6:00

3/12

12:00

3/12

18:00

3/13

0:00

3/13

6:00

3/13

12:00

3/13

18:00

3/14

0:00

3/14

6:00

3/14

12:00

3/14

18:00

3/15

0:00

3/15

6:00

3/15

12:00

3/15

18:00

3/16

0:00

7.47 ,7.54 ,7.61MPa abs

8 .7MPa abs

7.0MPa abs

0.000

0.200

0.400

0.600

0.800

1.000

3/11

12:00

3/11

18:00

3/12

0:00

3/12

6:00

3/12

12:00

3/12

18:00

3/13

0:00

3/13

6:00

3/13

12:00

3/13

18:00

3/14

0:00

3/14

6:00

3/14

12:00

3/14

18:00

3/15

0:00

3/15

6:00

3/15

12:00

3/15

18:00

3/16

0:00

0.38MPa abs

0.723MPa abs

RxWater

Level[mm]

RCIC

HPCS No Operation( Inoperative due to submersion of power source and inoperative auxiliary cooling system)

SRV

MUWC

RHR

PCV Vent

S/C Pressure (MPa)

D/W Pressure (MPa)

Earthquake14:46

Tunami15:23

RxPressure

[MPa]

D/W&

S/C

Pressure[M

Pa]

(Ref.) Fukushima Daini Unit 1 Plant Parameter and Operation

0(TAF)

3:50 ~ DepressurizationPressure Control

0:00 ~

3:45 ~

(18:30 Vent LineConfiguration Completed

Cold Shut Down14:46

Overscale

Restoration of RHR system

Major Activities at 1F


36/80


Work in complete darkness.

Many scattered objects werealso on the floor.

Connected temporarybatteries to recoverinstrumentations.

j

Factors disturbing the recovery work (inside the building)

Scramresponse

Preparationsfor waterinjection

Preparations

for venting

Waterinjection

started

Venting

Deterioratedoperability

due to thetsunami

Due to lack of power sources, initial recovery activities had to be conducted incomplete darkness, without any instrumentation, and without most

communications means.



37/80


Instruments were monitored wearing a full face mask with a flashlight incomplete darkness

Supervising at a deputysupervisors desk wearinga full face mask incomplete darkness

Checking indicated valuesonly with a flashlight in

complete darkness

j

Factors disturbing the recovery work (inside the buildings)

Scramresponse


Preparations

for venting

Waterinjection

started

Venting


due to thetsunami



38/80


Image of mobile power truck

Used batteries taken from cars for recovery of importantinstrumentations.

Put Engine-Generators to provide power for the control roomlightingsand PCV vent valve actuation.

Tried to connect a mobile power truck to P/C 2C with temporarycable. The hydrogen explosion of Unit 1 caused damage of thetemporary cable.

Scramresponse


Preparations

for venting

Waterinjection

started

Venting


due to thetsunami

j

Factors disturbing initial recovery of instrumentations and power supply

Hurdles for the work: Darkness and suspensions due

to aftershocks, tsunami alarms, Puddles, openings of manholes,

debris and other obstacles

caused by the tsunami, Influence of the hydrogen

explosions



39/80


1. Tried to inject fresh water using the diesel driven fireprotection pump (DDFP): failed. Unit 1: mechanical problem of the DDFP Unit 2: the DDFP was flooded

Unit 3: the RPV pressure was too high2. Injection of fresh water from underground water tank

(16units/site40m3/unit) using the fire engine pumps :succeeded but did not last for long time

3. Injection of sea water using the fire engine pumps.

Hurdles for the work: Interruptions due to aftershocks and tsunami alarms Damages of the fresh water lines due to the earthquake

Debris and damages of the gates caused by the tsunami R/B explosions (debris, damage of fire engines and other

devices, injury of field workers and fear of another explosion) No lights. Problem with the PHS telephone and radio

communication

Scramresponse


due to thetsunami

Waterinjection

started

Venting


Preparations

for venting

Factors disturbing alternative water injection into the reactors



40/80


Factors disturbing the recovery work (outside the buildings)

Scramresponse


due to thetsunami

Waterinjection

started

Venting


Preparations

for venting

Many obstacles on access routes disturbed access to the field.

Vehicles had to avoid passing over fire protection hoses laid in the field.

Almost no communication tools between the ERC and workers at thefield were available.



41/80


Scramresponse


due to thetsunami

Waterinjection

started

Venting

j

Factors disturbing the Primary Containment Vessel Venting Operation

Self-containedbreathing apparatus

72

AO

210

MO

1

AO

83

AO

90AO

0.549MPabs

RPV

D/W

RPVRPV

D/W

IA

IA

D/W0.528MPabs

0.954MPabs

213

AO

Shift workers operation tomanually open valve

MO

AO

AO

AO

AO

MO

Exhauststack

Closed

Closed

Closed

Closed

Solenoidvalve

Solenoid valve

Cylinder

Cylinder

D/W maximumoperating pressure:

0.528MPaabs

Ruptureddisc Broke at

0.549MPabs

Ventingpressure:0.954MPaabs


Preparations

for venting

No power source for the MO-valve Manual operation No power source to the solenoid valve Engine driven generator

Low IA pressure to actuate the AO-valve Engine driven air compressor

High radiation level in R/B


42/80


3.Other Relevant Items

How the Pre-planed Accident Management Worked


43/80


How the Pre planed Accident Management Worked(The Tsunami was beyond AM )

Facilities Outline Practical use at 1F-13 at 2F-1

Shutdown Recirculation Pump Trip

Alternative Rod Insertion

:CRs are fully inserted

Injecting

water

Alternative Injection by

MUWC /FP

:Injected from AM coupler

:Using Fire engineMUWC & FP aredowned as loss of AC power etc.

Automatic ADS :Manual operated as loss of power

.Containment

Cooling

Alternative Cooling byDrywell Cooler

Restoration of CCS

:Inoperable as loss of AC power

Hardened Vent : Manual operated (preparedline up)

Support of

SafetyFacilities

Interchangeability of 6.9kV

& 480V Power Sources

: Inoperable as loss of power including

the next(1~4) plant (But operable 1F-5,6 BUS tie)

Restoration ProcedureGuidelines (RHR & D/G)

: Cooling and Electric supply facilitiesare Inoperable

no relation couldn't apply partially apply apply

Presumption of Reactor Core State by Analysis Code (MAAP ) etc.


44/80


Unit 1

Almost no fuel was left at the originalposition, and fuel completely moveddownward after it damaged.

The moved fuel likely damaged RPVand is assumed that most of it had

dropped to the bottom of PCV. Dropped fuel is assumed to have

caused core concrete reaction.

As of Nov.21, water injection isconducted through the feed water

system and the temperature at bottomas well as inside the PCV remainstable below 100.

Therefore, it is evaluated that all themoved fuel is expected to be cooled

directly by water injection. It is alsoevaluated that the core concretereaction has been stopped.

Erosion depth by core concrete reaction:0.65m

Presumption of Reactor Core State by Analysis Code (MAAP ) etc.


45/80


Unit 2 & 3 Even though the fuel was damaged, it

is assumed that there has been no largedamage of the RPV that would make alarge amount of fuel dropped to thebottom of PCV.

There is a range in the evaluation result

from part of damaged fuel dropped tothe bottom of PCV to Almost all thefuel is left inside RPV.

If the part of damaged fuel were tohave dropped to the bottom of PCV, it

can be assumed that core concretereaction was caused.

Currently, water injection is conductedthrough the feed water system and CSsystem. The temperature in the PCV

remain stable below 100. Therefore, it is evaluated that all the

moved fuel is expected to be cooleddirectly by water injection. It is alsoevaluated that the core concrete

reaction has been stopped.

Erosion depth by core concrete reaction:Unit 2: 0.12m

Unit 3: 0.20m

Hydrogen Explosions at Units 1 and 3 R/B


46/80


Hydrogen Explosions at Units 1 and 3 R/B

Hydrogen is supposed to have leaked through heat affectedseals on the D/W flange, hatch and electric penetrations.Reactor building

D/W flange

Hatch

Electricpenetration

Move to upper floor bystairs or through hatches

1st

floor

2ndfloor

3rdfloor

4thfloor

5thfloor

RPV

Hydrogen Explosion at Units 4 R/B


47/80


Hydrogen generated in the Unit 3 reactor back-flowed intoUnit 4 through SGTS line.

AO

AO

AO

AO

AO

AO

AO

AO

AO

SGTS

SGTS

SGTS

SGTS

3------4

1F

3F

4F

5F

GL

2F

4

5 4

Ventinggas flow

Unit4 reactorbuilding

4th level east-sideexhaust duct

4th level west-sideexhaust duct

5th floor south-side exhaust duct

Back-flowgas Unit4Unit3

Exhauststa

ck

Hydrogen Explosion at Units 4 R/B

Measurement Result of Unit 4 SGTS Radiation Dose


48/80


Measurement Result of Unit 4 SGTS Radiation Dose

Number of Stored Fuel Assemblies and Decay Heat

in Spent Fuel Pool (SFP)


49/80


in Spent Fuel Pool (SFP)

Stored fuel assemblies Decay heat (MW)

Irradiated fuel Fresh fuel As of March 11 As of June 11

Unit 1 SFP 292 100 0.18 0.16

Unit 2 SFP 587 28 0.62 0.52

Unit 3 SFP 514 52 0.54 0.46

Unit 4 SFP 1331 204 2.26 1.58

Unit 5 SFP 946 48 1.01 0.76

Unit 6 SFP 876 64 0.87 0.73

Common SFP 6375 0 1.13 1.12

LOPA caused loss of cooling Largest Heat load in Unit 4, but

Rx well and DS pit was full

Water injected by helicopter, fire

engines, and then concrete pumps

No fuel was uncovered in anypools

Now all pools are cooled by heat

exchangers

Unit 4 Spent Fuel Pool Evaluation

Waterlevel(topoffuelrack=0

m)

Conditions of SFPs


50/80


Unit 3 SFP (Water surface and underwater)

As many debris have fallen into the SFP,the status of the fuel racks and fuels can

not be confirmed.

Unit 4 SFP (Water surface and underwater)

Although some debris have fallen into the

SFP, it can be confirmed that the status of

the fuel racks and fuels are normal.


51/80


. Current Status

and Roadmap towardsDecommissioning

Inside of 1F unit 2 PCV

Inside wall

Grating

Accumulated Water Processing Facilities


52/80


g

Process MainBldg.

Turbine Bldg.

Reactor Bldg.

Condenser

#1:91.2m3/d,FDW#2:187.2m3/d,FDW/CS

#3:288m3/d,FDW /CS

RPV

PCVSPT(B)

CesiumAdsorptionFacility

WastewaterSupply Tk

DesalinationPlant

Conc.SaltwaterReceivingTk

FreshwaterReceiving Tk

FiltrateTk Conc.Waste liq.Storage Tk

EvaporativeConcentrationApparatus

BufferTk

High Temp.Incinerator Bldg.

Sludge

Vessels

Accumulated WaterAccumulated WaterAccumulated WaterAccumulated Waterin Turbine Buildingin Turbine Buildingin Turbine Buildingin Turbine Building

Cumulative treated volume:approx.246,810m3

(As of Feb.21, 2012)

Temperature inside PCV got low and stable


53/80


Monitoring Data (at Site Boundary of Fukushima Daiichi)


54/80


:Sv/h as of 0:00 onJan. 16th , 2012Dose Rate Trend at the Site Boundary of

Fukushima Daiichi

Monitoring data at the site boundary of Fukushima Daiichi shows continuous decrease at

each monitoring post.Air dose rate measured at on-

site monitoring posts

WestGate

Main Gate

Unit1Unit2Unit3

Unit4

Monitoring Post(MP-1~8)Temporary Monitoring Post

Unit6Unit5

67

88

32

14

11

12

194

11284

27


55/80

Mid-and long term Roadmap towards the Decommissioning(1/2)


56/80


Period to the commencement of the fuel removal from

the Spent Fuel Pools (Within 2 years)-Commence the removal of fuels from the spent fuel pools(Unit 4 in 2 years)

-Reduce the radiation impact due to additional emissionsfrom the whole site and radioactive waste generated after theaccident (secondary waste materials via water processingand debris etc.) Thus maintain an effective radiation dose of

less than 1 mSv/yr at the site boundaries caused by theaforementioned.

-Maintain stable reactor cooling and accumulated waterprocessing and improve their credibility.

-Commence R&D and decontamination towards the removal

of fuel debris-Commence R&D of radioactive waste processing anddisposal

-Condition equivalent tocold shutdown

-Significant Suppression of

Emissions

Step 1,2 Phase 1

Dec. 16th 2011(Step 2 Completed) Within 2 years

Actions towards systematic staff training and allocation, improving motivation, and

securing worker safety will be continuously implemented.

Mid-and long term Roadmap towards the Decommissioning(2/2)


57/80


Within 2 years

Period to the end of thedecommissioning(In 30-40 years)

Phase 3

Within 10 years Within 30-40 years

Period to the commencement of the removal offuel debris (Within 10 years)

-Complete the fuel removal from the spent fuel

pools at all Units

-Complete preparations for the removal of fuel

debris such as decontaminating the insides of the

buildings, restoring the PCVs and filling the PCVs

with water. Then commence the removal of fueldebris (Target: within 10 years)

-Continue stable reactor cooling

-Complete the processing of accumulated water

-Continue R&D on radioactive waste processing

and disposal, and commence R&D on the reactor

facilities decommission

-Complete the fuel debris removal(in 20-25 years)

-Complete the decommission (in 30-

40 years)

-Implement radioactive waste

Actions towards systematic staff training and allocation, improving motivation, and

securing worker safety will be continuously implemented.

Phase 2


58/80


5.Lessons Learned and Countermeasures

Lessons Learned and Countermeasures


59/80


Thorough equipment protection measures against tsunami to prevent powerloss and loss of the heat removal function are important.

Preventing the flooding of buildings

Embankment

Flood Barriers & Walls

Preventing the flooding of important equipment

Water tight doors in R/B etc.

Embankment

Flood Barrier

Wall

WatertightDoors



60/80


Regardless of the initial cause of the accident, flexible alternative measureswith improved applications and mobility to prevent core damage againstlong simultaneous loss of AC and DC power and long loss of heatremoval function are important.

Enhancing high-pressure & low-pressure cooling water injectionManual startup of steam-driven cooling water injection equipment

Preparation ofmobile power trucks and backup water source

Establishment of water injection means using fire engines

Enhancing reactor depressurization

Preparation ofspare batteries and gas cylinders

Enhancing heat removal and cooling

Backup AC power

Preparation ofspare replacement motor for emergency sea water systems

Preparation of a portable mobile heat exchanger (pump, heat exchanger set) Securing power for monitoring instruments

Mobile power trucks

To RHRTo SFP

Sea

Heat exchanger truck



61/80


From the perspective of defense-in-depth, it is important to takefurther measures in case core damage does occur.

Preventing hydrogen accumulation in R/B

Opening holes on the roof ofR/B (top vent) etc.

Suppressing the release of radioactive materials

Preparation for water injection to the PCV through fire engines, etc

Backup AC power and modification of design to facilitate PCV

venting

It is important to prepare further equipment and auxiliary facilities for

support of on-site response.

Debris removal equipment

Communication methods

Lighting equipment

Protective equipment (protective wears, masks, APDs etc.)

Top vent



62/80


Without newly built Emergency Response Center, the post-accidentactivities could not have been carried out.

Measures taken after Niigata Chuetsu Oki Earthquake were effective:

Emergency response center in robust building (Seismic isolation,

Shielding, Communication, etc.)

Underground water tank and Fire Engines (3/site)

SlidingSlidingSlidingSliding

bearingbearingbearingbearing

Seismically Isolated ERCSeismically Isolated ERCSeismically Isolated ERCSeismically Isolated ERC

LaminatedLaminatedLaminatedLaminatedrubber bearingrubber bearingrubber bearingrubber bearing

Embankment (Kashiwazaki-Kariwa NPS)


63/80


Unit 1Unit 1Unit 1Unit 1----4444

: Reinforced concrete wall (image) :Clay embankment image

Unit 5Unit 5Unit 5Unit 5----7777

T.P.+15.0lene

10.0

3.0

T.P.+5.0

T.P.+15.0

T.P.+12.0

T.P.+15.0

T.P.+15.0

T.P.+15.0m line

Gate

Gate

Access road

Access road

Access road

Flooding barriers


64/80


Flood barrier wallFlood barrier plate

Watertight door

R/B

R/B

LouverVentilation holeDoor

Louver

Flood barrier plate(balcony type)

Flood barrier plate(closing type)

Watertight doors


65/80


Penetrations sealed with silicon rubber


66/80


Backup AC Power (Air Cooling GTG & Mobile Power Truck )


67/80


M/C 1CEmergencyM/C

Air cooling GTG

66kV BUS

Construction Power Tr

4500KVA

Air cooling GTGMobile power

trucks

500KVA Mobile

power trucks

Enhancing Reactor Depressurization


68/80


Spare cylindersSpare cylindersSpare cylindersSpare cylinders

2222ndndndnd

floor of R/Bfloor of R/Bfloor of R/Bfloor of R/B

Stand-by

System A cylindersSystem A cylindersSystem A cylindersSystem A cylinders

Regular useRegular use

System B System A

SRVs withSRVs withSRVs withSRVs with

ADS functionADS functionADS functionADS function

N2supply

N2supply

Manual switching by lowpressure

Stand-by

System B cylindersSystem B cylindersSystem B cylindersSystem B cylinders

Manual switching by lowpressure

SRVSRVSRVSRV

AccumulatorAccumulatorAccumulatorAccumulator

NO

Temporary switch

TemporaryTemporaryTemporaryTemporary

BatteryBatteryBatteryBattery

Temporary Spare Battery

Low Pressure Injection by Fire Engine


69/80


Sea water

Fire Engine

FiltratedWaterTankRun outRun outRun outRun out

InoperativeInoperativeInoperativeInoperative

R/B

Coupling for

fire fighting

FPFPFPFP----MUWCMUWCMUWCMUWCTie LineTie LineTie LineTie Line

O O

MCC1C-1-2

MCC1C-1-3

OO

MCC1C-1-5

GTG MobilePowerTruckEmergency M/C

M/C1C

MCC1C-1-2 MCC1C-1-5

P/C1C-1

RHR

MCC1C-1-3

Water Reservoir


70/80


Fresh water tankFresh water tankFresh water tankFresh water tank

T.P.+13.0mT.P.+13.0mT.P.+13.0mT.P.+13.0m

Water reservoirWater reservoirWater reservoirWater reservoir

T.P+45.0mT.P+45.0mT.P+45.0mT.P+45.0m

18,000m18,000m18,000m18,000m3333Water pipeWater pipeWater pipeWater pipe

Fresh water tankFresh water tankFresh water tankFresh water tank

T.P.+12.0mT.P.+12.0mT.P.+12.0mT.P.+12.0mWellWellWellWell

Alternative Heat Removal


71/80


Prepared

connector

Temporary Submerged

Pump

75kW

75kW Alternative Heat Exchanger Vehicle

T/BT/BT/BT/B

Sea waterSea waterSea waterSea water

TrTrTrTr

PPPP

To Submerged pumpTo Submerged pumpTo Submerged pumpTo Submerged pump

HxHxHxHx

T/B

Trench

MO

RHRIW Hx (A)

R/B

RHR HxFPC Hx

Alternative HeatExchanger vehicle

TemporarySubmergedPump

Mobile Power Truck

500kVA6600V

Tr Truck

6600V400VTemporarySubmerged

Pump

Sea water

intake channel

R/B

PCV Venting (Ensuring Actuation)


72/80


IA

IA

Exhauster

SGTS

StackRuptureDisk

SGTS(B

)SGTS(A)

PCVPCVPCVPCV

D/W

S/C

RPV

R/B

MOAO

AO

R/BBF4

Vital UPS

Vital UPSGTG Mobile

powertrucks

P/C1C-1

Emergency M/C

M/C1C

MCC1C-1-1

Vital UPS

MCC1C-1-4

Operation at

Main ControlRoom

MCC1C-1-1

R/BBF1

Manualoperation

SpareSpareSpareSpare

SpareSpareSpareSpare

PCV Venting (Manual Operation at Field)


73/80


Exhauster

SGTS

Stack

S/C vent prior use

RuptureDisk

SGTS(B)

SGTS(A)

RPV

R/B

OAO

AO

Manual operation possible

R/B

BF1

R/B

BF4 OpenOpenOpenOpen

AO-valvesmodified sothat manualoperation ispossible witha ratchetwrench

PCVPCVPCVPCV

D/W

S/C

ManualOperation

R/B top vent


74/80


R/BR/BR/BR/B

WireWireWireWire Lever LeverLeverLever blockblockblockblock

Provision of Heavy Machinery


75/80


Wheel loaderWheel loaderWheel loaderWheel loader

Crawler hydraulicCrawler hydraulicCrawler hydraulicCrawler hydraulicshovelshovelshovelshovel

Wheel loaderWheel loaderWheel loaderWheel loaderWheel loaderWheel loaderWheel loaderWheel loaderWheel loaderWheel loaderWheel loaderWheel loader

Crawler hydraulicCrawler hydraulicCrawler hydraulicCrawler hydraulicshovelshovelshovelshovel

Wheel hydraulicWheel hydraulicWheel hydraulicWheel hydraulicshovelshovelshovelshovel

Image of Light Oil Storage Facility


76/80


Fixed oilFixed oilFixed oilFixed oilfeed pumpfeed pumpfeed pumpfeed pump

Tank 1Tank 1Tank 1Tank 1 Tank 2Tank 2Tank 2Tank 2 Tank 3Tank 3Tank 3Tank 3

FillerFillerFillerFillerthroatthroatthroatthroat


FeedFeedFeedFeedthroatthroatthroatthroat

Underground oil storage facilityUnderground oil storage facilityUnderground oil storage facilityUnderground oil storage facility

Other cars andOther cars andOther cars andOther cars and

heavy machineryheavy machineryheavy machineryheavy machineryMiniMiniMiniMini----tanker (900 )tanker (900 )tanker (900 )tanker (900 )

Mobile power truckMobile power truckMobile power truckMobile power truck

PPPP

PPPP

Underground light oil tank(50K:2.4mX11.7m)X3




GTGGTGGTGGTG

GTGGTGGTGGTG

Portable PHS Antenna (Image)


77/80


650mm300mm

520mm

Storage rack

Door

Fiber cabledrum

IP phone

Cable drum100m

Web camera

(for future)

Junction box

To ERC

PortableGenerator

Switch

Switch

Switch

Switch

IP PHSantenna

Added Monitoring Cars


78/80


Portable Monitoring PostPortable Monitoring PostPortable Monitoring PostPortable Monitoring PostIonisation chamber type

survey meter

Dust SamplerDust SamplerDust SamplerDust Samplervane anemometer

Portable generatorPortable generatorPortable generatorPortable generator Satellite cell-phone

In Closing


79/80


Achieved Stable ConditionsCondition equivalent to cold shutdown

Significant suppression of radioactivity emissions

Commenced the phase 1of Mid-and-long-Term Roadmaptowards the Decommissioning of Fukushima Daiichi

Nuclear Power Units 1-4

Phase 1: Period to the commencement of the fuel

removal from the Spent Fuel Pools (Within 2 years)

Implementing measures to enhance safety of Kashiwazaki

Kariwa NPS.

Deployed mobile power trucks, additional fire engines,

spare pumps and motors, etc.


80/80


Thank you for your attention!

Facts Lessons FUKUGIMA

Documents