Date post: | 06-Apr-2018 |
Category: |
Documents |
Upload: | iaeainformation |
View: | 216 times |
Download: | 0 times |
of 76
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
1/76
All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 0
The Facts in the Recovery Process ofFukushima Nuclear Accident
March 21, 2012
@IAEA IEM, ViennaAkira Kawano
Tokyo Electric Power Company
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
2/76
All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 1
What I will present
1.How the Earthquake and the Tsunami affectedthe Power Supply at 1F and 2F sites ?
2.How the Accident Developed and was Stabilizedat 1F and 2F Sites ?
3.How We Responded to the Accident at 1F and2F Sites ?
4.Summary5.Reference
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
3/76
All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 2
How the Earthquake and the Tsunami Affectedthe Power Supply at 1F and 2F Sites ?
Unit 6Unit 5Unit 1Unit 2
Unit 3Unit 4
Unit 1
Unit 2Unit 3
Unit 4
Fukushma Daiichi(1F) Fukushma Daini(2F)
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
4/76
All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 3
Overview of Fukushima Daiichi NPS (1F)
and Fukushima Daini NPS (2F)
Plant UnitIn
Operation
Since
Plant
Type
Power
Output
(MWe)
Main
Contractor
Pre-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 HitachiShutdown for maintenanceFull 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
1 1982.4 BWR-5 1100 Toshiba Operating
2 1984.2 BWR-5 1100 Hitachi Operating
3 1985.6 BWR-5 1100 Toshiba Operating
4 1987.8 BWR-5 1100 Toshiba Operating
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
5/76
All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 4
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 DGlost 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 progress
Okuma Line 4L: Circuit breaker shutdown by protection relay activation
Ohkuma4L
Ohkuma3L
Ohkuma2L
Ohkuma1L
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
6/76
All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 5
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
Futaba
1L
Futaba
2L
Yonomori 2LYonomori 1L
For transmitting
power
For transmitting
power
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
7/76
All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 6
Damages of transmission line
& Shinfukushima substation by earthquake
500kV Disconnector275kV 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
Collapse CGeoEye
Collapse of filled soil & sand
Tower collapse
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
8/76All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 7
6.9kV 6.9kV
2F Offsite Power was secured after the TsunamiOffsite Power
500kV66kV
H STr
Unit #1, 2 STr Unit #3, 4 STr
/
EmergencyPower 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 scheduledmaintenance and substation trouble but recovered.
Many power centers and motors were damagedbecause of the flooding.
PPPP
EmergencyPower for Unit #2
EmergencyPower for Unit #3
EmergencyPower for Unit #4
/
P: Cooling Pumps
/ : Diesel Generator
/P
/P
/P
/P
Tomioka Line Iwaido Line
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
9/76All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 8
Integrity of Power Supply System After the Tsunami at 1F and 2F
*1 functionality lost due to inundation of power panels *2 functionality lost due to the damage of sea water system
Power panelCan/can
not be
usedPower panel
Can/can
not be
usedPower panel
Can/can
not be
usedPower panel
Can/can
not be
usedPower panel
Can/can
not be
usedPower panel
Can/can
not be
usedPower panel
Can/can
not be
usedPower panel
Can/can
not be
usedPower panel
Can/can
not be
usedPower panel
Can/can
not be
used
DG 1A DG 2A DG 3A DG 4A DG 5A(*2) DG 6A (*2) DG 1A DG 2A (*2) DG 3A (*2) DG 4A (*2)
DG 1B DG 2B
air-cooled(*1) DG 3B
DG 4Bair-cooled
(*1) DG 5B(*2) DG 6B
air-cooled DG DG 2 (*2) DG 3 DG 4 (*2)
HPCS DG (*2) DG 1 DG 2 (*2) DG 3 DG 4
M/C 1C M/C 2C M/C 3C M/C 4C M/C 5C M/C 6C M/C 1C M/C 2C M/C 3C M/C 4C
M/C 1D M/C 2D M/C 3D M/C 4D M/C 5D M/C 6D M/C 1D M/C 2D M/C 3D M/C 4D
M/C 2E M/C 4E HPCS DG
M/C M/C 1H M/C 2H M/C 3H M/C 4H
M/C 6A-1 M/C 1A-1 M/C 2A-1 M/C 3A-1 M/C 4A-1
M/C 6A-2 M/C 1A-2 M/C 2A-2 M/C 3A-2 M/C 4A-2
M/C 6B-1 M/C 1-1 M/C 2-1 M/C 3-1 M/C 4-1
M/C 6B-2 M/C 1-2 M/C 2-2 M/C 3-2 M/C 4-2
M/C 5SA-1 M/C 1SA-1 M/C 3SA-1
M/C 5SA-2 M/C 1SA-2 M/C 3SA-2
M/C 5SB-1 M/C 1SB-1 M/C 3SB-1
M/C 5SB-2 M/C 1SB-2 M/C 3SB-2
P/C 1C P/C 2C P/C 3C P/C 4C P/C 5C P/C 6C P/C 1C-1 P/C 2C-1 P/C 3C-1 P/C 4C-1
P/C 1D P/C 2D P/C 3D P/C 4D P/C 5D P/C 6D P/C 1C-2 P/C 2C-2 P/C 3C-2 P/C 4C-2
P/C 2E P/C 4E P/C 6E P/C 1D-1 P/C 2D-1 P/C 3D-1 P/C 4D-1
P/C 2A P/C 3A P/C 4A P/C 5A P/C 6A-1 P/C 1D-2 P/C 2D-2 P/C 3D-2 P/C 4D-2
P/C 2A-1 P/C 5A-1 P/C 6A-2 P/C 1A-1 P/C 2A-1 P/C 3A-1 P/C 4A-1
P/C 1B P/C 2B P/C 3B P/C 4B P/C 5B P/C 6B-1 P/C 1A-2 P/C 2A-2 P/C 3A-2 P/C 4A-2
P/C 5B-1 P/C 6B-2 P/C 1B-1 P/C 2B-1 P/C 3B-1 P/C 4B-1 P/C 1S P/C 3SA P/C 5SA P/C 1B-2 P/C 2B-2 P/C 3B-2 P/C 4B-2
P/C 5SA-1 P/C 1SA P/C 3SA
P/C 2SB P/C 3SB P/C 5SB P/C 1SB P/C 3SB
DC125V mainbus panel A
DC125V P/C
2A
DC125V mainbus panel 3A
DC125V mainbus panel 4A
DC125V P/C
5A
DC125V DISTCENTER 6A
DC125V mainbus panel A
DC125V mainbus panel A
DC125V mainbus panel A
DC125V mainbus panel A
DC125V mainbus panel B
DC125V P/C
2B
DC125V mainbus panel 3B
DC125V mainbus panel 4B
DC125V P/C
5B
DC125V DISTCENTER 6B
DC125V mainbus panel B
DC125V mainbus panel B
DC125V mainbus panel B
DC125V mainbus panel B
A RHRS A RHRS A RHRS A RHRS A RHRS A RHRS A RHRS A RHRS A RHRS A
B RHRS B RHRS B RHRS B RHRS B RHRS B RHRS B RHRS B RHRS B RHRS B
SW
- -
Regularuse
P/C
P/C 1A
Seawater
system
DC
power
supply
125V
DC
EmergencyDG
M/C
Regularuse
Emergency
use
M/C 2SB
M/C 2SA
M/C 3SA
M/C 3SB
M/C 2B
M/C 3A
M/C 5BM/C 4B
M/C 5AM/C 4A
M/C 3B
M/C 1S
M/C 1
M/C 2A
Emergencyuse
M/C 1A
Unit 3 Unit 5Unit 4 Unit 6
- -
Fukushima DaiichiUnit 1 Unit 2
Fukushima DainiUnit 1 Unit 2 Unit 3 Unit 4
1F:No off-site power available 2F:Off-site power survived
DG
6.9KVM
/C
480VPC
DC
O: operable X: damagedSea Water System
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
10/76All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 9
2. How the accident developedand was stabilized at 1F & 2F
Sites?
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
11/76All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 10
Fukushima Daiichi Units 1 - 4 Fukushima Daiichi Units 5 & 6 Fukushima Daini Units 1 - 4
Progress made by each plant towards cold shutdown (outline)
Units 1-3 in operation
Unit 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 beencontinuously improved
Currently the closed cyclecooling is in function
Sea water was initially injected intothe spent fuel pool; currently
injecting 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
Increase in spent fuel pool
temperature to near 70C
3/20
Units 5, 6 cold shutdown
Installation of temporary RHRS
Installation of temporary powersupply
In operation
[Power supply] One off-site powersupply 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 shutdown3/15 Unit 4 cold shutdown
RHRC motor was replacedInstallation of temporary power
supply
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
12/76All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 11
-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
0.38 MPa abs
0.723MPa abs
RxW
ater
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
R
xPressure
[M
Pa]
D/W
&S/C
Pressure[MPa]
0(TAF)
3:50 ~ DepressurizationPressure Control
0:00 ~
3:45 ~
(18:30Vent LineConfiguration Completed
Cold Shut Down14:46
Overscale
Restoration of RHR system
2F Unit 1 Plant Parameter and Operation
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
13/76All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 12
Operators initial response
MSIVs closed manually, and reactor
pressure controlled by SRVs.
RCIC actuated manually to maintain
reactor water level. RCIC repeated
automatic trip due to high water level
signal and manual restart.
MUWC actuated for alternative
water injection measure introduced
for Accident Management, as stated
in EOP manual for seamless water
injection.
Reactor depressurized and RCIC
stopped due to steam pressure
decrease.
Water level maintained by MUWC.
Sea
Steam
Water
Condensate Storage
Tank
RPV
Reactor Building
Heat Exchanger Building
Heat rejection byopening SRVs
Temperatureincrease
Tsunami floodingInoperable by
flooding
Equipment cooling system was notavailable.
RHRC Pump
RHRS Pump
RHR Pump
RCIC MUWC
MSIV
SuppressionChamber
(S/C)
Response at Main Control Room and TSC
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
14/76All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 13
0
1
2
3
4
5
6
7
8
3/11 3/12 3/13 3/14 3/15
(MPa [gage])
3/11 16:15 Reactor depressurization
started (SRV automatically opened)
3/14 10:05
LPCI and S/C
cooling and spray
by RHR(B)
3/14 13:40
Cold shutdown3/12 0:00
MUWC started
3/11 15:36 - 3/12 4:58
RCIC Operation
(intermittent)
-1000
-500
0
500
1000
1500
3/11 3/12 3/13 3/14 3/15
(mm)
Out of measurement range
3/11 16:15
Reactor depressurization started
(SRV automatically opened)
Successful Reactor Cooling during Transient
Reactor Pressure (Unit 1)Reactor Water Level (Unit
1)
Securing uninterrupted water injection throughout the
depressurization process with RCIC at high pressure condition andMUWC at low pressure condition was a critical factor for successfulreactor cooling.
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
15/76All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 14
0
20
40
60
80
100
120
140
3/11 3/13 3/15 3/17 3/19
3/12 06:2007:47
S/C injection by FCS(A)
3/12 07:10 D/W spray
3/12 07:37 S/C spray
3/13
11:3213:26 14:2914:37
D/W spray
0
50
100
150
200
250
300
3/11 3/13 3/15 3/17 3/19
kPa[gage]
3/14 01:24
RHR(B) started with
S/C cooling mode
3/17 20:0320:20Water transfer from
Condenser to S/C via
CST to monitor
Condenser water level
3/13
11:3213:26
14:2914:37
D/W spray
3/12 06:2007:45
S/C injection by FCS(A)
3/12 07:10 D/W spray
3/12 07:37 S/C spray
S/C Temperature (Unit 1)S/C Pressure (Unit 1)
S/C water temperature reached 100C (212F). It eventually increased up to about 130C (266F).
Water injected to S/C through Hydrogen Recombiner cooler discharge line in orderto mitigate temperature and pressure increases.
Alternative injection to reactor using MUWC switched to D/W spray, then S/C spray.
S/C temperature decreased after restoration of RHR.
EOP includes an alternative water injection measures employing MUWC .
Flexible approach to cool S/C using Hydrogen Recombiner worked well.
Efforts to Control Temperature and Pressure in PCV
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
16/76All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 15
Preparation for Venting
PCIS and SGTS actuated to secure isolation of the PCV and
maintained negative pressure of the reactor building.
Judging from the increasing PCV pressure trend and projectedrestoration time, as a back-up plan, TSC decided to make PCV ventline up ready.
PCV pressure went up to about 280 kPa [gage] before restoration ofRHR, but did not reach its design maximum pressure 310 kPa [gage].
PCV vent line up was made ready as a back-up plan. This would enable feed and breed cooling to avoid potential
core damage.
(As restoration of cooling capability was successful and coldshutdown was achieved, venting was not conducted actually.)
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
17/76All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 16
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
7.28,7.35,7.41MPa 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)
RxWater
Level[m
m]
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
4:00Fresh Water 80t 14:53
18:18 - 2521:3014:52
Earthquake14:46
Tunami15:27
Operation Unclear
Order for Vent
8:03 14:30 D/W Pr decrease confirmed
Unit 1 R/BExplosion 15:36
Core Damage Started due toMAAP Analysis
Rx
Pressure
[MP
a]
D
/W
&S/C
P
ressure[MPa]
1F Unit 1 Plant Parameter and Operation
0(TAF)Rx water level data revealed incorrect afterward
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
18/76All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 17
-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
0:000
2
4
6
8
10
In 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
0.53MPa abs
0.954MPa abs
RxWater
Level[m
m]
RCIC
HPCI No Operation
SRV
FP/FireEngine
PCV Vent
Fuel Range (A) (mm)
Fuel Range (B) (mm)
CAMS D/W(A)(Sv/ CAMS S/C(A)(Sv/
Rx Pressure (A) (MPa)
Rx Pressure (B) (MPa)
S/C Pressure (MPa)
D/W Pressure (MPa)
19:Sea Water
Order for Vent Preparation 17:30
Depressurization~18:00
Earthquake14:46 Tunami
15:27
(2:55) Operation confirmed
(11:00Vent LineConfiguration Completed
Unit1 R/BExplosion15:36
Core Damage Started due toMAAP Analysis
Rx
Pressure
[MP
a]
D
/W
&S/C
P
ressure[MPa]
1F Unit 2 Plant Parameter and OperationUnit3 R/BExplosion11:01
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)
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
19/76All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 18
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
0.954MPa
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,7.51MPa,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
I n Operat ion(Over Scale )
RxWater
Level[m
m]
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)
Rx Pressure (A) (MPa)
Rx Pressure (B) (MPa)
S/C Pressure (MPa)
D/W Pressure (MPa)
16:30Sea Water
Order for Vent Preparation 17:30
Earthquake14:46 Tunami
15:27
Unit1 R/BExplosion15:36
Core Damage Started due toMAAP Analysis
Rx
Pressure
[MP
a]
D
/W
&S/C
P
ressure[MPa]
1F Unit 3 Plant Parameter and OperationUnit3 R/BExplosion11:01
Order for Preparation17:12
0(TAF)
(11:36) Trip
Automatic Start(12:35)
(16:03)
(2:42) Stop
13:12Sea WaterFresh Water9:25
(8:41Vent 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
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
20/76All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 19
3. How We Responded to theAccident at 1F & 2F Sites?
- What difficulties existed- What were effectively utilized
- How the difficulties were overcome- Testimonies
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
21/76All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 20
Establishing an alternative method to inject water into the
reactor pressure vessel (RPV)
Venting of the primary containment vessel (PCV)
Recovery of the most important instrumentations:
reactor water level
reactor pressure
drywell pressure
wet-well (suppression chamber: S/C) pressure
Recovery of the lights in the control rooms and other powersupply sources
What 1F site focused on during March 11-15
M j A ti iti t F k hi D ii hi U it 1
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
22/76All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 21
Activities were done in complete darkness due to lack of power sources.
Work in complete darknessIn the service building. Manyscattered objects were alsoon the floor.
Temporary power supplyConnect temporarybatteries to recoverinstrumentations.
Major Activities at Fukushima Daiichi Unit 1
Factors disturbing the recovery work (inside the building)
Scram
response
Preparationsfor waterinjection
Preparations
for venting
Waterinjectionstarted
Venting
Deterioratingoperabilitydue to the
tsunami
M j A ti iti t 1F
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
23/76All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 22
Image of a power supply cart
Used batteries taken from cars for recovery of important
instrumentations. Put Engine-Generators to provide power for the control room
lightings and PCV vent valve actuation.
Tried to connect a mobile power supply vehicle to P/C 2C/4Dwith temporary cable. The hydrogen explosion of Unit 1&3
caused damage of the temporary cable.
Scram
response
Preparationsfor waterinjection
Preparations
for venting
Waterinjectionstarted
Venting
Deterioratedoperabilitydue to the
tsunami
Major Activities at 1F
Factors disturbing initial recovery of instrumentations and power supply
Hurdles for the work:
Darkness and suspensions dueto aftershocks, tsunami alarms,
Puddles, openings of manholes,
debris and other obstaclescaused by the tsunami,
Influence of the hydrogenexplosions
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
24/76All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 23
Number of Aftershocks Greater than M 5.0
3/11Dates (from March 11, 2011 to Dec. 5th, 2011)
12/54/1
DailyNum
berofAftershock
sGreaterthanM
5.0
CumulativeN
umberofAftersho
cksGreaterthanM5.0
On March 11th alone
155 times > M 5.0
37 times > M6.03 times > M7.0
Total during first week358 times > M 5.0
Major Activities at Fukushima Daiichi Unit 1
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
25/76All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 24
Instruments were monitored wearing a full face mask with a flashlight incomplete darkness
Supervising (2)Supervising at a deputysupervisors desk wearing
a full face mask incomplete darkness
Supervising (1)Check indicated values onlywith a flashlight in completedarkness
Major Activities at Fukushima Daiichi Unit 1
Factors disturbing the recovery work (inside the buildings)
Scram
response
Deterioratingoperabilitydue to the
tsunami
Waterinjectionstarted
Venting
Preparationsfor waterinjection
Preparations
for venting
M j A i i i 1F U i 1
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
26/76All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 25
Many obstacles on access routes disturbed access to the field.
Vehicles had to avoid passing over fire protection hoses laid in the field.
Most of the prepared communication tools between the ERC and thecontrol room were unavailable.
Scram
response
Deterioratingoperabilitydue to the
tsunami
Waterinjectionstarted
Venting
Preparationsfor waterinjection
Preparations
for venting
Major Activities at 1F Unit 1
Major Activities at Fukushima Daiichi Unit 1
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
27/76
All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 26
Scram
response
Deterioratingoperabilitydue to the
tsunami
Waterinjectionstarted
Venting
Major Activities at Fukushima Daiichi Unit 1
Containment Vessel Venting Operation (1)
Self-containedbreathing apparatus
Two valves, a PCV vent valve (MO valve) and a S/C vent valve (AO valve: small) were selectedas the target for manual PCV venting operation .
Manual valve operation were planned to be conducted by 3 teams with 2 shift workers per team(one worker per team would be difficult due to the total darkness) and shift supervisors and vice-
supervisors were selected to the team members. Equipment for the teams included fire-resistant clothing, self-contained breathing apparatus,
APD, survey meter and flash light.
At 9:03, it was confirmed that evacuation from the vicinity of south side of the NPS completed.At 9:04, the team members headed to the site for the venting operation.
72AO
210
MO
1AO
83
AO
90AO
0.549MPabs
RPV
D/W
RPVRPV
D/W
IA
IA
D/W0.528MPabs
0.954MPabs
213
AO
Shift workers operation tomanually openvalve
MO
AO
AO
AO
AO
MO
Exhauststack
Closed
Closed
Closed
Closed
Solenoidvalve
Cylinder
Cylinder
D/W maximumoperating pressure:
0.528MPaabs
Ruptureddisc Broke at
0.549MPabs
Venting
pressure:0.954MPaabs
Preparationsfor waterinjection
Preparations
for venting
Major Activities at Fukushima Daiichi Unit 1
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
28/76
All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 27
Waterinjectionstarted
Venting
Major Activities at Fukushima Daiichi Unit 1
Containment Vessel Venting Operation (2)
72AO
210MO
1AO
83
AO
90AO
0.549MPabs
RPV
D/W
RPVRPV
D/W
IA
IA
D/W0.528MPabs
0.954MPabs
213
AO
25%
1st team proceeded to site to operatePCV vent valve (MO valve) on the2nd level of the R/B, and implementedoperation to open the valve manually.
R/B 2nd levelR/B 1st level
South-sidedouble door
To 2nd level bysoutheast stairs PCV vent valve
(MO valve)
North-sidedouble door
Operation to open PCV ventvalve (MO valve) successful
Access route to PCV vent valve (MO valve)
Manualopening
operationsuccessful
MO
MO
AO
AO
AO
AO
Ruptured disc
Broke at 0.549MPabs
Air stack
Closed
Closed
Closed
Solenoid valve
Solenoid valve
Cylinder
Cylinder
D/W maximum operating pressure
Venting pressure
Closed
(25% open)
Operation to manually openPCV vent valve (MO valve)
Scram
response
Deterioratingoperabilitydue to the
tsunami
Preparationsfor waterinjection
Preparations
for venting
Major Activities at Fukushima Daiichi Unit 1
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
29/76
All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 28
Waterinjectionstarted
Venting
Major Activities at Fukushima Daiichi Unit 1
Containment Vessel Venting Operation (3)
72AO
210MO
1AO
83
AO
90AO
0.549MPabs
RPV
D/W
RPVRPV
D/W
IA
IA
D/W0.528MPabs
0.954MPabs
213AO
25%
2nd team entered the torus room (R/B
B1F), but the valve was located at adirection of 180 degrees from where theteam entered the torus room.
The survey meter rose up to the limit onthe way, and the team members returned.
R/B 1st floor R/B B1F
S/C ventvalve
(AO valve)
Dose at thenorth-sidedouble
door washigh, andsouth-boundcourse wasselected
Manual operation was abandoned
and another means were selected
Access route to S/C vent valve (AO valve)
Manual openingoperation
successful
AO
AO
Manual openingoperation abandoned
due to high dose
AO
AOMO
MORuptured disc
Broke at 0.549MPabs
Air stack
Closed
Closed
Closed
Solenoid valve
Solenoid valve
Cylinder
Cylinde
r
D/W maximum operating pressure
Ventingpressure
Closed
(25% open)
Operation to manually open S/Cvent valve (AO valve) valves
South-sidedouble door
North-sidedouble door
Deterioratingoperabilitydue to the
tsunami
Scram
response
Preparationsfor waterinjection
Preparations
for venting
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
30/76
All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 29
What were available for the recovery work after the tsunami?
There were only the following limited number of
devices and tools available!
Fire Engines: only a few people knew howto operate them.
Flashlights
Cable Tools (screwdrivers, etc.)
Batteries taken from cars Engine driven Generators* Engine driven Air Compressors**They were in the warehousesof the affiliated companies anddifficult to find.
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
31/76
All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 30
System Status after the Tsunami at 2F
secure (power, pump and motor all working) loss of function (power, pump or motor inoperable)
malfunction (inoperable due to factor other than power, pump or motor)
RHR(A) inoperable due to the
loss of power source
and cooling system
inoperable due to the
loss of cooling system
inoperable due to the
loss of cooling system
inoperable due to the
loss of cooling system
RHRC/RCRS(A,C)
inoperable due to the
submerge of powersource and motor
inoperable due to the
submerge of powersource and motor
inoperable due to the
submerge of powersource and motor
inoperable due to the
submerge of powersource and motor
EECW(A) inoperable due to the
submerge of power
source and motor
inoperable due to the
submerge of power
source and motor
inoperable due to the
submerge of power
source and motor
inoperable due to the
submerge of power
source and motor
inoperable due to the
loss of power source
and cooling system
inoperable due to the
loss of cooling system
inoperable due to the
loss of cooling system
inoperable due to the
loss of cooling system
inoperable due to
submerge
inoperable due to the
loss of cooling system
inoperable due to the
loss of cooling system
inoperable due to the
loss of cooling system
RHR(B) inoperable due to the
loss of cooling system inoperable due to the
loss of cooling system stand-by inoperable due to the
loss of cooling system
RHRC/RCRS(B,D) inoperable due to the
submerge of power
source and motor
inoperable due to the
submerge of power
source
stand-by inoperable due to the
submerge of power
source and motor
EECW(B) inoperable due to the
submerge of power
source and motor
inoperable due to the
submerge of power
source
operation inoperable due to the
submerge of power
source
inoperable due to the
loss of cooling system
inoperable due to the
loss of cooling system stand-by
inoperable due to the
loss of cooling system
inoperable due tosubmerge
inoperable due to theloss of cooling system
operation inoperable due to theloss of cooling system
inoperable due to the
loss of cooling system
inoperable due to the
loss of cooling system
inoperable due to the
loss of cooling system
inoperable due to the
loss of cooling system
MUWC
(alternative water injection)MUWC() stand-by stand-by stand-by stand-by
stand-by stand-by stand-by stand-by
RHR(C )
EDG(B)
RWCU
RCIC
Unit 4Unit 3Unit 2Unit 1System
RHR(A)
including coolingsystems
RHR(B)
including cooling
systems
LPCS
EDG(A)
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
32/76
All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 31
Field Walkdown
Challenges in conducting field walkdown
Under continuous tsunami alerts, walkdown must be done in the field where alot of debris, openings and flooding areas existed in the dark.
Preparation for emergency evacuation in case of further tsunami and other
safety measures for personnel going out to the field. Successful access to the field was 6 hours after the tsunami flooding.
Field walkdown after the tsunami
Plant equipment status checked / componentfunctionality verified.
Results were summarized and shared at TSC.
TSC set priorities on recovery of RHR (B) coolingsystems by replacing motors and supplying powerfrom survived electrical buses and mobile powervehicles through temporary cable.
In order to establish a well-prioritized restoration strategy,degree of damage and possibility of short-term restoration
must be understood through walkdown.
L i ti i E Sit ti
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
33/76
All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 32
Logistics in Emergency Situation Procurement and transportation of Materials and Equipment
Emergency procurement of motors, cable, mobile power vehicles, fuel oil andmobile transformers with close cooperation between site TSC and corporate ERC.
Rated output of some motors were not the same as that of the original motors.TSC determined to install them based on the evaluation of actual load conditions.
Difficulties experienced in logistics
Motors were transported from Toshiba by a chopper of SDF and from KashiwazakiKariwa NPP by trucks.
Securing redundant communication measures were critically important when majorhighway was damaged and public cell phone services were disrupted.
Mobile Power Vehicles Fuel oil delivery to the siteNecessary materials andequipment prioritized and listed
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
34/76
All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 33
Emergency Restoration Efforts in the Field
Pumps of RHR cooling systems (RHRC, RHRS, EECW) were inspected.
Motors were replaced for pumps in RHRC and EECW.
In order to restore the inundated electrical buses, temporary cable andhigh voltage mobile power vehicles were deployed.
Temporary cable was laid from survived power cubicles in Rad-Waste
Building and Unit 3 Heat Exchanger Building.Drawing made at TSC for temporary cable laying
Motor replacement
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
35/76
All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 34
Recovering Electricity
Temporary cable of 9 km length was laid by about 200 personnel within a day.Usually this size of cable laying requires 20 personnel and more than 1 month period.
After the pumps for RHR cooling systems were restored and temporary cable was laidRHR (B) of Unit 1 started up at 1:24 on March 14 and other units followed.
Finally at 15:42 on March 14with the start up of Unit 4 RHR,RHR of all four reactors ofFukushima Daini startedoperation.
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
36/76
All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 35
Temporary Power Supply and Motor Replacement at 2FUnit #3
Hx
Building
Unit #1
Reactor
Rad-WasteBuilding
TSC
Main Office
Unit #4Turbine
Unit #2Hx
Building
Unit #1Hx
Building
Unit #4Hx
Building
Unit #2
ReactorUnit #3Reactor
Unit #4
Reactor
Unit #3Turbine
Unit #1Turbine
Unit #2Turbine
MobilePowerSupplyTruck(500kVA)
Temporary Cables
MobilePowerSupplyTruck(500kVA)
6.6kV/480VTransformer
6.6kV/480VTransformer
About 9 km of temporary cableswere laid and motors were
replaced.
System Status after Emergency Restoration at 2F
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
37/76
All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 36
System Status after Emergency Restoration at 2F
secure (power, pump and motor all working) loss of function (power, pump or motor inoperable)
malfunction (inoperable due to factor other than power, pump or motor)
RHR(A) inoperable due to
loss of power source
and coolin s stem
inoperable due to
loss of cooling
s stem
inoperable due to
loss of cooling
s stem
inoperable due to
loss of cooling
s stem
RHRC/RCRS(A,C) inoperable due to
submerge of power
source and motor
inoperable due to
submerge of power
source and motor
inoperable due to
submerge of power
source and motor
inoperable due to
submerge of power
source and motor
EECW(A) inoperable due to
submerge of power
source and motor
inoperable due to
submerge of power
source and motor
inoperable due to
submerge of power
source and motor
inoperable due to
submerge of power
source and motor
inoperable due to
loss of power source
and cooling system
inoperable due to
loss of cooling
system
inoperable due to
loss of cooling
system
inoperable due to
loss of cooling
system
inoperable due to
submerge
inoperable due to
loss of cooling
system
inoperable due to
loss of cooling
system
inoperable due to
loss of cooling
system
RHR(B) operation operation operation operation
RHRC/RCRS(B,D) operation operation operation operation
EECW(B) operation operation operation operation
stand-by stand-by stand-by stand-by
operable using t ie-line
from unit #2 stand-by stand-by stand-by
inoperable due to the
loss of purge line
inoperable due to the
loss of purge line
inoperable due to the
loss of purge line
inoperable due to the
loss of purge line
MUWC
(alternative water injection)MUWC(B) stand-by stand-by stand-by operation
inoperable for loss of
core pressure
inoperable for loss of
core pressure
inoperable for loss of
core pressure
inoperable for loss of
core pressureRCIC
RWCU
EDG(B)
RHR(C )
Unit 2 Unit 3 Unit 4System
RHR(A)
including coolingsystems
RHR(B)
including cooling
systems
Unit 1
LPCS
EDG(A)
O i f th 10 U it Si lt A id t
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
38/76
All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 37
Overview of the 10-Unit Simultaneous Accidents
Date1F 2F
1 2 3 4 5 6 1 2 3 4
3/11
3/12
3/13
3/14
3/15
3/16-19
3/20
3/14 17:00
3/14 1:24RHR
3/14 7:13RHR
3/14 15:42RHR
3/14 18:00
3/15 7:15
3/12 12:15
3/20 14:30
3/19 22:14RHR
3/12 8:13D/G-6B
3/22 10:35P/C-4D
3/22 10:36P/C-4D
3/20 15:46P/C-2C
3/20 15:46P/C-2C
3/19 5:00RHR
3/20 14:30
Station Black-Out
Loss of Ultimate Heat Sink
Cold Shutdown
3/12 15:36 Unit 1 Explosion
3/15 6:00-6:10 Unit 4 Explosion (?)
3/14 11:01 Unit 3 Explosion
3/11 15:27 1st Tsunami, 15:35 2nd Tsunami 3/11 15:22~ Tsunamis
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
39/76
All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 38
Testimonies from the Field (Operators)
In an attempt to check the status of Unit 4 D/G, I wastrapped inside the security gate compartment. Soon the
tsunami came and I was a few minutes before drowning,when my colleague smash opened the window and savedmy life.
In total darkness, I could hear the unearthly sound of SRV
dumping steam into the torus. I stepped on the torus to
open the S/C spray valve, and my rubber boot melted. The radiation level in the main control room was
increasing 0.01 mSv (1 mrem) every 3 seconds but Icouldnt leaveI felt this was the end of my life.
I asked for volunteers to manually open the vent valves.
Young operators raised their hands as well; I wasoverwhelmed.
Unit 3 could explode anytime soon, but it was my turn togo to the main control room. I called my dad and askedhim to take good care of my wife and kids should I die.
Testimonies from the Field (Maintenance Persons)
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
40/76
All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 39
Testimonies from the Field (Maintenance Persons)
We saw our car crashed by the explosion of the Unit 3. Ifwe had gotten on the car a few minutes earlier, all of uswould have been dead.
We were replacing fire hoseswhen the explosion of Unit 3occurred. We felt almost dying since many large rubbleswere falling down to us.I urgently ran underneath a nearbyfire engine. One of my colleagues got injuries in his leg andstomach.
There were so many manholes opened by the tsunami. Inorder to lay cables, we had to proceed step by stepcarefully checking safety in the complete darkness.
We were working in the Unit 3/4 control room when theexplosion occurred. I was resigned to my fate. Dose ratewas going up in the room after the explosion and wedesperately tried to find places with lower dose rate.
After replacing an air cylinder for the PCV ventilation of
Unit 3, I heard sound of steam and saw white mist aroundus. I got into a panic for a while.
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
41/76
All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 40
4. Summary
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
42/76
All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 41
The 1F accident was caused by the simultaneous loss of multiple safetyfunctions due to far beyond design basis of tsunami. The main factors of the
accident are the simultaneous loss of total AC power and DC power fora extended period of timeand the loss of the heat removal function ofthe emergency seawater system for a extended period of time.
Preparations had been previously made to receive power from neighboringunits in the event that AC power and DC power were not available. During the
accident, direct tsunami damage was so widespread that the neighboringunits were all in the same condition.
Summary of Lessons Learned
Carefully consider the robustness of current design ofnuclear power plants and emergency preparedness
againstbeyond design basis eventsthat could lead tocommon cause failuresregardless of their assumedprobability demonstrating a continuous learningorganization.
Technical Lessons Learned
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
43/76
All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 42
Success path regarding Cooling and Heat Removal from the Reactor
1)Promptly initiate core injectionmethods using high-pressure coolingwater injection equipment
2)Initiate depressurization methods before losingof high-pressure cooling water injection function
3)Stable low-pressure cooling water injection methodsshould be available during the depressurization stage
4)Provide reliable PCV venting methods (heat removal
through the atmospheric discharge of heat)
5)Provide measures to restore the
cooling function using sea water
6)Provide measures which enable necessary monitoring for those operationand plant conditions.
It is inevitable to maintain water injection and core cooling function thoroughlyand continuously even in poor environmental conditions.
Technical Lessons Learned
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
44/76
All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 43
2F Key Success Factors
Accident mitigation by applying EOP and AMG
Prioritized restoration strategy based on Field Walkdown
Prompt restoration with success of emergencyprocurement for materials and equipment
Logistics for long term emergency response
Organizational integrity: Leadership, Communication,Accountability, Professionalism
Organization and Management Features
Design/Engineering Features
Availability of most of M/C, P/C and Battery
Availability of off-site power
Website Information
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
45/76
All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 44
Website Information
TEPCO English websitehttp://www.tepco.co.jp/en/nu/fukushima-np/index-e.html
Internal Investigation Committee Interim Report (Dec. 2nd, 2011)http://www.tepco.co.jp/en/press/corp-com/release/11120205-e.html
Report on initial responses to the accident (Dec. 22nd,2011)
The Latest version of accident Timeline (Dec.22nd, 2011)English version will be on the following website soon.
http://www.tepco.co.jp/en/press/corp-com/release/11122208-e.html
INPOSpecial Report on Fukushima Daiichi Nuclear Power Stationhttp://www.nei.org/resourcesandstats/documentlibrary/safetyandsecurity/reports/special-report-
on-the-nuclear-accident-at-the-fukushima-daiichi-nuclear-power-station
EPRIFukushima Daini Independent Review and Walkdown
http://my.epri.com/portal/server.pt?Abstract_id=000000000001023422
http://www.tepco.co.jp/en/nu/fukushima-np/index-e.htmlhttp://www.tepco.co.jp/en/press/corp-com/release/11120205-e.htmlhttp://www.tepco.co.jp/en/press/corp-com/release/11122208-e.htmlhttp://www.nei.org/resourcesandstats/documentlibrary/safetyandsecurity/reports/special-report-on-the-nuclear-accident-at-the-fukushima-daiichi-nuclear-power-stationhttp://www.nei.org/resourcesandstats/documentlibrary/safetyandsecurity/reports/special-report-on-the-nuclear-accident-at-the-fukushima-daiichi-nuclear-power-stationhttp://my.epri.com/portal/server.pt?Abstract_id=000000000001023422http://my.epri.com/portal/server.pt?Abstract_id=000000000001023422http://my.epri.com/portal/server.pt?Abstract_id=000000000001023422http://www.nei.org/resourcesandstats/documentlibrary/safetyandsecurity/reports/special-report-on-the-nuclear-accident-at-the-fukushima-daiichi-nuclear-power-stationhttp://www.nei.org/resourcesandstats/documentlibrary/safetyandsecurity/reports/special-report-on-the-nuclear-accident-at-the-fukushima-daiichi-nuclear-power-stationhttp://www.nei.org/resourcesandstats/documentlibrary/safetyandsecurity/reports/special-report-on-the-nuclear-accident-at-the-fukushima-daiichi-nuclear-power-stationhttp://www.nei.org/resourcesandstats/documentlibrary/safetyandsecurity/reports/special-report-on-the-nuclear-accident-at-the-fukushima-daiichi-nuclear-power-stationhttp://www.nei.org/resourcesandstats/documentlibrary/safetyandsecurity/reports/special-report-on-the-nuclear-accident-at-the-fukushima-daiichi-nuclear-power-stationhttp://www.nei.org/resourcesandstats/documentlibrary/safetyandsecurity/reports/special-report-on-the-nuclear-accident-at-the-fukushima-daiichi-nuclear-power-stationhttp://www.nei.org/resourcesandstats/documentlibrary/safetyandsecurity/reports/special-report-on-the-nuclear-accident-at-the-fukushima-daiichi-nuclear-power-stationhttp://www.nei.org/resourcesandstats/documentlibrary/safetyandsecurity/reports/special-report-on-the-nuclear-accident-at-the-fukushima-daiichi-nuclear-power-stationhttp://www.nei.org/resourcesandstats/documentlibrary/safetyandsecurity/reports/special-report-on-the-nuclear-accident-at-the-fukushima-daiichi-nuclear-power-stationhttp://www.nei.org/resourcesandstats/documentlibrary/safetyandsecurity/reports/special-report-on-the-nuclear-accident-at-the-fukushima-daiichi-nuclear-power-stationhttp://www.nei.org/resourcesandstats/documentlibrary/safetyandsecurity/reports/special-report-on-the-nuclear-accident-at-the-fukushima-daiichi-nuclear-power-stationhttp://www.nei.org/resourcesandstats/documentlibrary/safetyandsecurity/reports/special-report-on-the-nuclear-accident-at-the-fukushima-daiichi-nuclear-power-stationhttp://www.nei.org/resourcesandstats/documentlibrary/safetyandsecurity/reports/special-report-on-the-nuclear-accident-at-the-fukushima-daiichi-nuclear-power-stationhttp://www.nei.org/resourcesandstats/documentlibrary/safetyandsecurity/reports/special-report-on-the-nuclear-accident-at-the-fukushima-daiichi-nuclear-power-stationhttp://www.nei.org/resourcesandstats/documentlibrary/safetyandsecurity/reports/special-report-on-the-nuclear-accident-at-the-fukushima-daiichi-nuclear-power-stationhttp://www.nei.org/resourcesandstats/documentlibrary/safetyandsecurity/reports/special-report-on-the-nuclear-accident-at-the-fukushima-daiichi-nuclear-power-stationhttp://www.nei.org/resourcesandstats/documentlibrary/safetyandsecurity/reports/special-report-on-the-nuclear-accident-at-the-fukushima-daiichi-nuclear-power-stationhttp://www.nei.org/resourcesandstats/documentlibrary/safetyandsecurity/reports/special-report-on-the-nuclear-accident-at-the-fukushima-daiichi-nuclear-power-stationhttp://www.nei.org/resourcesandstats/documentlibrary/safetyandsecurity/reports/special-report-on-the-nuclear-accident-at-the-fukushima-daiichi-nuclear-power-stationhttp://www.nei.org/resourcesandstats/documentlibrary/safetyandsecurity/reports/special-report-on-the-nuclear-accident-at-the-fukushima-daiichi-nuclear-power-stationhttp://www.nei.org/resourcesandstats/documentlibrary/safetyandsecurity/reports/special-report-on-the-nuclear-accident-at-the-fukushima-daiichi-nuclear-power-stationhttp://www.nei.org/resourcesandstats/documentlibrary/safetyandsecurity/reports/special-report-on-the-nuclear-accident-at-the-fukushima-daiichi-nuclear-power-stationhttp://www.nei.org/resourcesandstats/documentlibrary/safetyandsecurity/reports/special-report-on-the-nuclear-accident-at-the-fukushima-daiichi-nuclear-power-stationhttp://www.nei.org/resourcesandstats/documentlibrary/safetyandsecurity/reports/special-report-on-the-nuclear-accident-at-the-fukushima-daiichi-nuclear-power-stationhttp://www.nei.org/resourcesandstats/documentlibrary/safetyandsecurity/reports/special-report-on-the-nuclear-accident-at-the-fukushima-daiichi-nuclear-power-stationhttp://www.tepco.co.jp/en/press/corp-com/release/11122208-e.htmlhttp://www.tepco.co.jp/en/press/corp-com/release/11122208-e.htmlhttp://www.tepco.co.jp/en/press/corp-com/release/11122208-e.htmlhttp://www.tepco.co.jp/en/press/corp-com/release/11122208-e.htmlhttp://www.tepco.co.jp/en/press/corp-com/release/11122208-e.htmlhttp://www.tepco.co.jp/en/press/corp-com/release/11122208-e.htmlhttp://www.tepco.co.jp/en/press/corp-com/release/11120205-e.htmlhttp://www.tepco.co.jp/en/press/corp-com/release/11120205-e.htmlhttp://www.tepco.co.jp/en/press/corp-com/release/11120205-e.htmlhttp://www.tepco.co.jp/en/press/corp-com/release/11120205-e.htmlhttp://www.tepco.co.jp/en/press/corp-com/release/11120205-e.htmlhttp://www.tepco.co.jp/en/press/corp-com/release/11120205-e.htmlhttp://www.tepco.co.jp/en/nu/fukushima-np/index-e.htmlhttp://www.tepco.co.jp/en/nu/fukushima-np/index-e.htmlhttp://www.tepco.co.jp/en/nu/fukushima-np/index-e.htmlhttp://www.tepco.co.jp/en/nu/fukushima-np/index-e.htmlhttp://www.tepco.co.jp/en/nu/fukushima-np/index-e.html8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
46/76
All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 45
Thank you for your attention!
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
47/76
All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 46
5. References
Intensit of the earthq ake at the po er stations
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
48/76
All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 47 47
Intensity of the earthquake at the power stations
*: The records were stopped approximately 130-150 seconds after recording started.
Observation Point
(The lowest basement of
reactor buildings)
Observed DataMaximum Response Accelerationagainst Basic Earthquake Ground
Motion (Gal)Maximum Response
Acceleration (gal)
Horizontal
(N-S)
Horizontal
(E-W)Vertical
Horizontal
(N-S)
Horizontal
(E-W)Vertical
Fukushima
Daiichi
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
Fukushima
Daini
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
In Fukushima Daiichi the observed data partially exceeded the maximum response acceleration with respect to the
design-basis earthquake, however most data was below the baseline
Note) Standard ground motion Ss: Seismic motion that was newly established to evaluate seismic safety, taking into account the
earthquakes, etc., that could occur around the power station, based on the revised seismic design review guidelines.
Intensity of the earthquake at the power stations
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
49/76
All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 48
In Fukushima daiich observation record partially exceeded the design-basis earthquake
ground motion, however it was confirmed to be almost the same level
0.02 0.05 0.1 0.2 0.5 1 2 50
1000
2000
3000
()
(Gal)
(h=0.05)
0.02 0.05 0.1 0.2 0.5 1 2 50
1000
2000
3000
()
(Gal)
(h=0.05)
Fukushima daiich
periodsperiods
0 50 100 150-800
-400
0
400
800
(Gal)
550
0 50 100 150
-800
-400
0
400
800
(Gal)
277
Fukushima daini
Observation recordsDesign-basis seismic ground motion Ss-1HDesign-basis seismic ground motion Ss-2HDesign-basis seismic ground motion Ss-3H
Observation recordsDesign-basis seismic ground motion Ss-1HDesign-basis seismic ground motion Ss-2HDesign-basis seismic ground motion Ss-3H
Unit 2W-E Unit 3N-S
timestimes
Acceleration
Gal
Acceleration
Gal
550 277
Accele
ration
Gal
Acceleration
Gal
Intensity of the earthquake at the power stations
Inundated Areas at 1F
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
50/76
All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 49
C)GeoEye
Inundated Areas at 1F
Inundation throughout almost all areas where main buildings sitedUnits 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 majorUnit-1-4 buildings:
O.P.10m
Elevation of majorUnit-5,6 buildings:
O.P.13m
Location of Openings from which Sea Water
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
51/76
All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 50
O . P .+ 1 3 m
O . P .+ 1 0 m
O .P .+ 4 mO .P .+ 4 m
3u Emergency D/Gair inlet louver
p gcould Flow into Main Buildings
(Fukushima Daiichi Nuclear Power Station)
Turbinebuilding
Reactorbuilding
Unit 6 D/G building
Unit 5Unit 6
Unit 1 Unit 2 Unit 3 Unit 4
Openings at the ground level fromwhich sea water could flow into buildingsOpenings connected to undergroundtrenches/ducts where sea water could flowinto buildings
Inundated Areas at 2F
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
52/76
All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 51
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. 12~14.5mInundation height in area south of Unit 1: OP approx. + 15~16m
Limited area was flooded
Inflowedintensively
C)GeoEye
Unit 2 Unit 1Unit 3Unit 4
Elevation of majorUnit-1-4 buildings:
O.P.12m
Location of Openings from which Sea Waterld fl i t M i B ildi
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
53/76
All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 52 52
could flow into Main Buildings(Fukushima Daini Nuclear Power Station)
Inside Unit 1 heat exchanger buildingUnits 3 & 4
Sea side of turbinebuilding
Openings at the ground level from which sea water could flow into buildingsOpenings connected to underground trenches/ducts where sea water could flow into buildings
Heat exchangerbuilding
Turbinebuilding
Reactorbuilding
Unit1
Unit2
Unit3
Unit4
Tsunami Height @1F v s 2F
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
54/76
All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 53
Base levelO.P.0m
Reactor
building
Ocean-sidearea Main building area
breakwater
Design basistsunami heightO.P.+5.2m
Site levelO.P. +12m
Water
intake
Inundation height apx. O.P. +6.5 - 7mSafety measures has taken
against 5.2m Tsunami height
Site levelO.P. +4m
Turbine building
Tsunami Height @1F v.s. 2F
49
The new design basis Tsunami height for 1F & 2F were evaluated based on the JSCE Tsunami assessmentmethodology. (1F: O.P.+5.7m, 2 F: O.P.+5.2m)
The countermeasures were implemented at both NPSs, such as pump motor elevation raised @1F andopenings sealed @2F, that were all equivalent from the viewpoint of resistance against Tsunami hazard.
The 15m class Tsunami caused by M9.0 class earthquake that accidentally attacked 1F was far beyond design
basis and whatever evaluation and whatever countermeasures did not matter at this time.1F
2F
O.P.Onahama Point
Hx building
Assumed highesttsunami water level
O.P. +5.7m
Base levelO.P. 0m
-
-
-
-Assumed highest
tsunami water level
O.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 highesttsunami water level
O.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
Design basistsunami heightO.P.+5.7m
Differences in Tsunami that hit Fukushima Daiichi
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
55/76
All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 54 54
and Daini NPSs
1050
100150
0
2
4
6
8
10
12
14
[m]Sea floor
displacement[m]
Fukushima
Daiichi
Fu
kushima
Da
ini
Maximumtsunamiheight
m
Peaks coinciding
Tsunami height: High
Peaks not coinciding
Tsunami height: Low
Same amplification rate
Water levelfluctuation fromeach blockTime T
Warm colored blocksgenerated massivetsunami 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 Model
Permitted Design Basis(1) Tsunami assessment
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
56/76
All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 55
g ( )
Tsunami assessment in construction permit
Fukushima NPSs
Historical tsunamis of Iwate and Miyagi coast were larger than that of FukushimaApproved 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
Permitted Design Basis(2) Tsunami assessment
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
57/76
All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 56
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/tsunami_eng.html
In JSCE- 2002, assumed 8 earthquakes individually. March
11 Earthquake occurred over several areas simultaneously.
Tsunami Assessment was revised based on the JSCE (Japan
Society of Civil Engineers) Method,2002
Damage Status of Unit 1 & 2 Emergency DG and Emergency High
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
58/76
All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 57
Unit 1 Unit 2
Equipment
Installedbuilding
Installed floor
Possibility
ofuse
StatusEquipme
ntInstalledlocation
Installedfloor
Possibility ofuse
Status
DG
DG 1A T/B B1FL Submerged DG 2A T/B B1FL Submerged
DG 1B T/B B1FL Submerged DG 2BShared
pool1FL
M/Csubmergedcannot be
used
(M/C)
Emergencyhigh
voltageswitchb
oard
M/C 1C T/B 1FL Water
damageM/C 2C T/B B1FL Submerged
M/C 1D T/B 1FL Water
damageM/C 2D T/B B1FL Submerged
M/C 2E Sharedpool
B1FL Submerged
Voltage Switchboard (Immediately after the Tsunami)
Damage Status of Unit 3 & 4 Emergency DG and Emergency High
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
59/76
All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 58
Unit 3 Unit 4
Equipment
Installedlocation
Installed floor
Possibility
ofuse
StatusEquipme
ntInstalledlocation
Installed
floor
Possibility ofuse
Status
DG
DG 3A T/B B1FL Submerge
d DG 4A T/B B1FL Submerged
(Constructionin progress)
DG 3B T/B B1FL Submerge
d DG 4BShared
pool1FL
M/Csubmergedcannot be
used
(M/C)
Emergencyhigh
voltageswitchboard
M/C 3C T/B B1FL Submerge
d M/C 4C T/B B1FL Submerged(Inspection
in progress)
M/C 3D T/B B1FL Submerge
d M/C 4D T/B B1FL Submerged
M/C 4E Sharedpool
B1FL Submerged
Voltage Switchboard (Immediately after the Tsunami)
Damage Status of Unit 5 & 6 Emergency DG and Emergency High
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
60/76
All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 59
Unit 5 Unit 6
Equipment
Installedlocation
Installed
floor
Po
ssibility ofuse
Status EquipmentInstalledlocation
Installed
floor
Possibility ofuse
Status
DG 5A T/B B1FL
Relatedequipment
Waterdamage
DG 6A R/B B1FL
Relatedequipment
Waterdamage
DG 5B T/B B1FL
Relatedequipment
Waterdamage
DG 6BDGbuilding
1FL
HPCSD/G R/B B1FL Related
equipmentWater
damage
(M/C)Emerge
ncyhigh
voltageswitchb
oard
M/C 5C T/B B1FL Submerged M/C 6C R/B B2FL
M/C 5D T/B B1FL Submerged M/C 6D R/B B1FL
HPCSDG M/C
R/B 1FL
Voltage Switchboard (Immediately after the Tsunami)
Fukushima Daiichi: DG System Outline
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
61/76
All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 60
All functionwas lost after
the tsunami
Power was
secured inUnit 6 (B)only
[Fukushima Daini: DG System Outline]
Power wassecured inUnit 3(B)(H) andUnit 4 ()only
Sea water-cooled DG (10)
Unit 1 (A)(B), Unit 2 (A), Unit 3 (A)(B), Unit 4 (A), Unit 5 (A)(B), Unit 6 (A)(H)
Air-cooled DG (3)
Unit 2 (B), Unit 4 (B), Unit 6(B)
Sea water-cooled DG (12)Unit 1 to Unit 4(A)(B)(H)
Sea waterpump
D/GHeatexchanger
Sea
Outsideair
Air cooler D/G
Cooling water pump
Heatexchanger
Sea waterpump
Heatexchanger
Cooling waterpump
D/GSea
Power Access/Restoration Status Immediately
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
62/76
All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 61
yafter 1F-1,2 Shutdown
Date Operation and Restoration Status
March 11 Temporary MCR lighting on (Temporary small engine generator)
March 12
Power source for Unit 1 Instrument restored (Temporary smallengine generator)
Power source for Unit 1 Instrument restored (power source cart)
Temporary small engine generator destroyed by H2 explosion
Temporary MCR lighting on (another temporary small enginegenerator)
March 19 Backup transformer ~ Unit 1 & 2 temporary M/C (A) cable laidMarch 20 Off-site power restored (P/C2C power received)
Power Access/Restoration Status Immediately
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
63/76
All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 62
after 1F-3,4 Shutdown
Date Operation and Restoration Status
March 11 Temporary MCR lighting on (Temporary small engine generator)
March 13 P/C 4D restored (power source cart)
March 14
Yonomori Line 1L step-down transformer cart (66/6.9kW)connected to the Shin-Fukushima Substation
Yonomori Line 1L ~ Okuma Line 3L connected
Power source for Unit 1 Instrument restored (power source cart)The power source cart destroyed by H2 explosion
March 18 Unit 3 & 4 MC, Switch installation location
March 22 Off-site power restored (P/C4D power received)
Power Access/Restoration Status Immediately
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
64/76
All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 63
after 1F-6 Shutdown
Date Operation and Restoration Status
March 11
DG6B startup (6A and 6H were shut down by the tsunami,6B is an air-cooled type
SGTS(B) startup, DC125V/250V (B system) restoration
March 12 DC125V/250V (A system) restoration
March 13 MUWC(B) startup
March 19
RHR 6B startup, temporary RHRS alternative pump startup(power source cart)
DG6A startup (March 21 shutdown)
March 20 Cold shutdown condition
March 22 Off-site power restored (M/C6C, 6D power received)
March 23Temporary RHRS alternative pump switched to off-sitepower
Power Access/Restoration Status Immediately
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
65/76
All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 64
Date Operation and Restoration Status
March 12 DC125V/250 restoration
March 13 MUWC(A), SGTS(A) startup
March 18 Temporary RHRS alternative pump startup (power source cart)
March 19 RHR 5C startup
March 20 Cold shutdown condition
March 22 Off-site power restored (M/C6C, 6D power received)
March 23 Temporary RHRS alternative pump switched to off-site power
after 1F-5 Shutdown
Recovery Process of I&C equipments @1F (1/2)
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
66/76
All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 65
Recovery Process of I&C equipments @1F (1/2)
After tsunami Total loss of instrumentations due to loss
of offsite power and DC 125V
March 11-14: to install temporary batteries to importantinstrumentations, such as reactor water level, reactorpressure, D/W pressure, S/C pressure etc. (1F-1-3: March 11,
1F-5/6: March 14) and to start to obtain plant data
March 22-25: to recover AC 120V bus for I&C (1F1: March23, 1F2: March 25, 1F3/4: March 22)
Present: to prioritize the recovery of redundantinstrumentations for their reliability and to change step by stepfrom temporary battery to original power source
Recovery Process of I&C equipments @1F (2/2)
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
67/76
All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 66
y q p @ ( )
May 9: to go into R/B to calibrate the D/W pressureinstrument @1F1
May 10-12: to calibrate the fuel zone reactor water levelinstrument @1F1
- water level assumed as lower than -500cm of TAF
June 3-4: to install the temporary reactor pressure andpressure instrument at the test line of fuel zone reactorwater level instrument @1F1, to obtain more precise data onreactor pressure and water level
June 22-24: to install the temporary reactor pressure andpressure instrument at the test line of fuel zone reactor
water level instrument @1F2
- not successful due to rapid evaporation of water inside instrumentation line byhigh PCV temperature
Current status of important instrumentations @1F
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
68/76
All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 67
p
Parameter/unit
1F1 1F2 1F3 1F4 1F5 1F6
Reactorwater level
N/A
Reactorpressure
N/A
Reactorwater temp.
Not sampled Not sampled Not sampled N/A
Temperature around
RPV N/A N/A N/A
D/Wpressure
N/A N/A N/A
S/Cpressure
N/A N/A N/A
CAMS radmonitor
D/WS/C
D/WS/C
D/WS/C
N/A N/A N/A
S/Ctemparature
- - -calibrated,assumed to be intact, under continuous observation, failure
Unit 1 Isolation Condenser
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
69/76
All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 68
Unit 1 Isolation Condenser
RPV
Primary Containment
Open to the Air
Fire protection systemPure water make up system
MO
system systemIsolationCondensor
1B
10A10B
3A
3B
PLR PP
MO
MO
MO
MO
MO
MO
MOMO
MO
1A
2BA
4A
4BInitiating system by
opening the valve
Reactor steamiscooled byIsolationcondenser coolanttank
Condensate water returnback to RPV driven bynatural convection force
Heated water in the tankreleased to the open air
MSIV
Function of the Isolation condenser
Depressurization of the reactor by steam condensation during reactor Isolation(MSIV closure condition)
Redundancy design(2 systems)
1F Unit 1 Schematic System Diagram (After Tsunami )
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
70/76
All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 69
Sea
TbCondenser
H/W
Gen
CST
FiltratedWaterTank
SLC
Stack
Sea
CCS
D/GCCSW
SRV
CRD
HPCI
CPRFP
W
CS MUWCDD FP
IC
S/C vent valve
D/W vent valveRPV
from
CSTH/W
Sea
:Operable:Inoperative dueto power loss
: BrieflyOperative
Summary of the Plant Behavior in Unit 1 (1/2)
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
71/76
All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 70
The automatic isolation interlock of the IC was actuated due to the loss of powercaused by the tsunami and then lost its function. Afterwards, the reactor waterlevel decreased in a short period of time and the core was exposed (Dropped toTAF), leading to the core damage. During this time, it was difficult to understandplant status due to the loss of power.
Based on the analysis results, it is evaluated that the core would have beendamaged regardless of the continuation of the operation of the IC after 18:18.
When the water level gauge was temporarily restored using a temporary powersource after 21:00 on March 11, a reading was obtained showing that the reactorwater level was above TAF. However at this point, there was not enoughinformation to comprehensively determine that this reading was erroneous. At theEmergency Response Headquarters on the site and the Head Office, it was not
deemed at this point that the IC had stopped. The possibility of the core damagewas recognized due to the increase in dose rate in front of the double doors of thereactor building at around 23:00 on March 11 and the unusually high reading forthe dry well pressure that was obtained for the first time at around 0:00 on March12.
Summary of the Plant Behavior in Unit 1 (1/2)
Summary of the Plant Behavior in Unit 1 (2/2)
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
72/76
All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 71
On March 12 at around 3:00, the reactor pressure decreased, although reactordepressurization operation was not conducted. This implies that damage to thereactor cooling water pressure boundary had occurred due to core damage. Thisimplies that core damage might have progressed to a considerable extent in ashort period of time.
Based on the results using the accident analysis codes, it took about 3 hours to
drop to TAF after the earthquake and about 4 hours until core damage began,which indicates the rapid event progress to the core damage. This result isconsistent with the events actually observed.
Summary of the Plant Behavior in Unit 1 (2/2)
1F Unit 2 Schematic System Diagram (After Tsunami)
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
73/76
All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 72
y g ( )
Sea
TbCondenser
H/W
Gen
CST
FiltratedWaterTank
SLC
Stack
Sea
RHR
D/GRHRS
SRV
CRD
HPCI
LPCPMD-RFP
W
CS
MUWC DD FP
S/C vent valve
D/W vent valve
:Operable:Inoperative dueto power loss
RPV
TD-RFP
fromCSTH/W
CSTRCIC
HPCP
Sea
:Inoperative
Summary of the Plant Behavior in Unit 2
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
74/76
All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 73
As the RCIC of Unit 2 functioned for a relatively long period of time, the core
decay heat was lower than immediately after shutdown. However as the high-pressure systems (RCIC) lost its function, decrease in the reactor water levelstarted.
About 1 hour and 20 minutes later after the RCIC shutdown, the fire enginespump was started up and preparations for low-pressure water injection wereready. However the SRV did not immediately operate during reactor
depressurization.
It is considered that core damage occurred because low-pressure water injectiondid not function immediately after the SRV was activated and reactordepressurization was achieved. Because of the rapid decrease in the retainedwater due to the outflow of steam to the S/C associated with reactor
depressurization, cooling function degraded furthermore.
According to the analysis by using the MAAP code, it is evaluated that coredamage started due to the decrease in reactor water level followed bydegradation of the function of the RCIC.
Summary of the Plant Behavior in Unit 2
1F Unit 3 Schematic System Diagram (After Tsunami)
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
75/76
All Rights Reserved 2011The Tokyo Electric Power Company, Inc. 74
Sea
TbCondenser
H/W
Gen
CST
FiltratedWaterTank
SLC
Stack
Sea
RHRD/GRHRS
SRV
CRD
HPCI
LPCPMD-RFP
W
CS
MUWC DD FP
S/C vent valve
D/W ventvalve
RPV
TD-RFP
fromCSTH/W
CSTRCIC
HPCP
Sea
:Operable:Inoperative dueto power loss:Inoperative
Summary of the Plant Behavior in Unit 3
8/2/2019 The Facts in the Recovery Process of Fukushima Nuclear Accident (Kawano)
76/76
In Unit 3, preparations for low-pressure water injection were performed by
activating the diesel-driven fire pump. However, because the reactor pressurewas higher than the water injection pressure, switching to low-pressure waterinjection was not immediately successful after shutdown of the high-pressuresystems (HPCI). This caused degradation of cooling and thus leading to coredamage.
S/C venting was conducted and repeated several times. The monitoring carreading near the main gate increased temporarily. However no large increase inthe background level was observed.
In addition, the hydrogen that was generated following the core damage was notcompletely retained in the PCV and leaked into the reactor building, and is
considered to have caused the explosion of the reactor building.
Summary of the Plant Behavior in Unit 3