Incorporated Administrative Agency
Japan Nuclear Energy Safety Organization
Niigataken Chuetsu-oki Earthquake and its
Influences on the Kashiwazaki-Kariwa NPP
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Incorporated Administrative Agency
Japan Nuclear Energy Safety Organization
Summary of the Earthquake and
Situation of the Kashiwazaki-Kariwa NPP
• Summary of the Earthquake
– Occurrence: July 16, 2007 at 10:13 am JST
– Earthquake Source:
• 17km below the seabed off Jo-chuetsu area in Niigata
prefecture (37°33.4′North、138°36.5′East）
• Epicenter Distance: 16km from the NPP
– Magnitude: 6.8
• Situation of the NPP
– When the earthquake occurred:
Niigata city
Kashiwazaki-Kariwa NPP
• Unit 2 was in start-up
• Unit 3, 4 and 7 were in normal operation
• Unit 1, 5 and 6 were out of operation for the periodic
inspections
Epicenter
– Units 2, 3, 4 and 7 were automatically shut down
following the high seismic acceleration trip signals
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Unit 1
Unit 2
Unit 3
Rx. Coolant Temp.
Unit 2
Unit 4
Unit 7
Japan Nuclear Energy Safety Organization
Unit 6
Unit 5
Rx. Water Level
19:40 <100℃
under Stat up
Unit 3
23:07 <100℃
100% Power
Unit 4
100% Power
Unit 7
7/17 6:54 <100℃
7/17 1:15 <100℃
100% Power
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Incorporated Administrative Agency
Japan Nuclear Energy Safety Organization
Unit 1 RPV Inspection Schedule
August
September
Phase 1
8/21
Phase 2
October
November
December
Phase 3
8/23
Visual inspection using
under water TV camera
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Unit 1 : Phase 1 Inspection
Flange
Guide Rod
Feed Water Sparger
Upper Grid
Core Shroud
Core Spray Pipe
Core Spray Sparger
As a result of phase 1
inspection, the abnormality
such as the damage /
transformation / the falling
off was not confirmed.
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Japan Nuclear Energy Safety Organization
Unit 1 : Flange
Guide Rod
Flange
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Unit 1 :Guide Rod
Guide Rod
FW Sparger
Core Spray Pipe
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Japan Nuclear Energy Safety Organization
Unit 1 :Feed Water Sparger
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Unit 1 :Core Spray Pipe
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Unit 1 :Core Spray Sparger
Core Shroud(upper ring)
Core Spray Sparger
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Japan Nuclear Energy Safety Organization
Unit 1 :Upper Grid
LPRM
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Incorporated Administrative Agency
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Unit 1 : RPV base bolts(A,As)
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Incorporated Administrative Agency
Japan Nuclear Energy Safety Organization
Unit 1 : Leakage of water into B5 floor
Break of Fire Extinguishing Pipe (B,C)
Reactor Combination Building
Pene
Duct
B1 Floor
Water Flow-in
B2 Floor
B3 Floor
B4 Floor
B5 Floor
Sump
Leakage of water into B5 floor of
the reactor combination building (Unit 1)
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Incorporated Administrative Agency
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Unit 1 : Oil Tank (B,C)
Land Subsidence
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Unit 3 :Fire of House Transformer(1/3)
(B,C)
As for the duct,
16 - 18cm dropped
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Unit 3 :Fire of House Transformer(2/3)
House Transformer
Bus Duct
1 – 3 cm
dropped
20 – 25 cm
dropped
Bedrock
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Incorporated Administrative Agency
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Unit 3 :Fire of House Transformer(3/3)
Start-up Transformer
Unit 7
6
5
4
2
1
Unit 3 Main Transformer
House Transformer
Unit 3
Main
Generator
Normal Bus
Fire of House Trans. was not safety related problem
Emergency Bus
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Unit 3 : DG(A,As)
Upside
Downside
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Unit 3 : HCU (A,As)( Hydraulic Control System (CRD))
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Unit 3 : MSIV (A,As)
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Unit 3 : PLR Pump (A,As)
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Unit 3 : RHR Pump (A,As)
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Unit 3 : Blow-out Panel came off
(B,C)
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Unit 3 : Displacement of the main exhaust duct
(B,C)
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Unit 6 : Leakage of water including
radioactive materials
(B,C)
Leakage of water including radioactive
materials into non-controlled area
in the reactor building
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Incorporated Administrative Agency
Japan Nuclear Energy Safety Organization
Unit 6 : Leakage of water including
radioactive materials
Leakage of water including radioactive
materials into non-controlled area
in the reactor building
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Incorporated Administrative Agency
Japan Nuclear Energy Safety Organization
Unit 6 : Damage of the reactor building
overhead crane
Motor
Motor
Damaged
Damage found on the coupling of the drive axis
of the reactor building overhead crane
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Incorporated Administrative Agency
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Unit 7 : Detection of radioactive materials in the
main exhaust duct
Reactor Building
Building Ventilation
Still Working
after Plant Shutdown
Reactor
Filter
Turbine
Condenser
Turbine Gland
Steam Exhauster
Filter
Main Exhaust Duct
Turbine
Building
Main Exhaust
Duct
Monitoring
House
Rare Gas Hold
-up Equipment
Detection of radioactive materials in the main exhaust duct resulting from
loss of the steam seal inside the turbine
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Other (B,C)
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Incorporated Administrative Agency
Japan Nuclear Energy Safety Organization
Solid waste storage warehouse
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