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Structural Integrity of Fukushima-Daiichi SSCs After The 2011 Great East Japan Earthquake

(PR21)

September 6, 2012IEM 3, IAEA ,Vienna

Kazuyuki NAGASAWA

2012 Tokyo Electric Power Company. All rights reserved. 1

� Unit #1 to #3 of 1F site (Fukushima-Daiichi NPS) shut down automatically by “Seismic SCRAM” and experienced Loss of Off-site Powerright after the GEJE.

� It is expected that safety functions were maintained until the tsunami hit.

� TEPCO confirmed structural and functional integrity of SSCs of 1F Site before the tsunami hit based on the following.

�Visual Inspections�Operation Records�Seismic Response Analysis : Unit 1 - 3�Representative Unit 5 Walkdown and Seismic Response Analysis

Introduction


� Original DBE was much conservative than current DBE Ss and observed record at the range of 0.1 - 0.2 sec of natural period.

Observed Records of GEJE

Unit 1 Unit 2 Unit 3

Introduction

Proper Period [s] Proper Period [s]

Sei

smic

Int

ensi

ty

Sei

smic

Int

ensi

ty

Sei

smic

Int

ensi

ty

Observed (North-South direction)Observed (East-West direction)Original Design (North-South direction)Original Design (East-West direction)Ss ( NSEW envelope )

Observed (North-South direction)Observed (East-West direction)Original Design (North-South direction)Original Design (East-West direction)Ss ( NSEW envelope )

Observed (North-South direction)Observed (East-West direction)Original Design (NSEW envelope )Ss ( NSEW envelope )

Proper Period [s]


Visual Inspections

�Damage condition of unit 1-3 was visually inspected in the limited area.�No damage on the IC system (isolation condenser) for unit 1.�No damage inside the torus room of unit 2.�No damage even for non seismic classified components in

turbine building for unit 1-3.

�Visual inspection for unit 1-3 was conducted for limited area due to high radiation level, however, within the scope of those inspection, both of safety related and no safety related components were almost unaffected by the earthquake.


Visual Inspection for the IC (Unit 1)

No structural damage was found.

Unit 1


Visual Inspection for the Torus Room (Unit 2)

No structural damage was found.

Direction to PCVSoutheast S/C manholeLower part of Torus Room

Route of northeast Upper part of the route of northeast

North S/C manhole

Upper part of the south route

Upper part of the southeast S/C manhole

Access route of self-propelled remote camera

Unit 2


No damage by the earthquake was found.Unit 3 Unit 2

1st floor

2nd floor

Unit 1 Unit 3 Unit 2 Unit 1

Turbine driven reactor feed water pumpAir-conditioning duct・Air-conditioning duct is partially swollen and damaged maybe by explosion

Turbine Building auxiliary cooling water system surge tank

6.9kV Metal clad switchgear 1A・Signs of tsunami flooding

Isolated phase bus cooling fan・Signs of tsunami flooding

480VPower center 2A

Turbine Building auxiliary cooling water system pump

Heater

Instrument air compressor

Visual Inspection for the T/B


�Unit 1-3 were safely shut down, and plant parameter such as reactor water level and pressure were controlled.� Type of alarm recorder� Records of reactor water level / pressure

�No Evidence showing damage of RPV boundary� Records of PCV pressure / temperature

�All EDGs were actuated under the loss of off-site power condition.� Records for transient recorder

Operation Records after GEJE


All control rods were fully inserted by seismic SCRAM

Seismic SCRAM Seismic SCRAM

Full insertion of all control rods Full insertion of

all control rods

Seismic SCRAM

Full insertion of all control

rods

Operation Records : Type of Alarm Recorder

Unit 1 Unit 2

Unit 3


The water level and the pressure were controlled

Seismic SCRAM

Control of water level by IC Control of

pressure by IC

Seismic SCRAM

Decrease in pressure

following IC operation

Increase in pressure

following IC shutdown

It is assumed that the

tsunami hit

Increase in pressure following closure of the main steam isolation valve

Off-site power loss, Main steam isolation valve closed IC

automatic startup

< Reactor Water Level > < Reactor Pressure >

Red：：：：Reactor Water LevelGreen：：：： Reactor Water Level ( Fuel Range )

Reactor Pressure

Operation Records : RPV Water Level and Pressure

Unit 1


Red：：：：Reactor Water Level

Green：：：：Reactor Pressure

Seismic SCRAM

The water level and the pressure were controlled.

< Unit 2 > < Unit 3>

Tsunami hit

Closure of the main steam isolation valve, Pressure control by SRV.

Change in water level due to RCIC operation

Seismic SCRAM

Change in water level due to RCIC operation

Unit 2 Unit 3

Operation Records : RPV Water Level and Pressure


Increase in differential

pressure following an increase in

containment vessel pressure

Decrease in suppression chamber pressure

following suppression chamber cooling

Seismic SCRAM

Seismic SCRAM

Increase in pressure following shutdown of the

containment vessel air-conditioning

Primary containment vessel pressureSuppression chamber differential pressure

Primary containment vessel pressure Primary containment vessel temperature

Increase in temperature following

shutdown of the containment vessel

air-conditioning

Operation Records : PCV Pressure and Temperature

Unit 1

Tsunami hit

No sign of leakage from RPV boundaryUnit 1


Primary containment vessel pressurePrimary containment vessel temperature

Seismic SCRAM

Seismic SCRAM

Increase in temperature

following shutdown of the

containment vessel air-conditioning




Seismic SCRA

Seismic SCRAM

Primary containment vessel pressure Primary containment vessel temperatureIncrease in temperature

following shutdown of the containment vessel air-

conditioning




Securement of EDG voltage

Securement of EDG voltage

Operation Records : EDG Transient Recorder

Unit 2

Unit 1

EDGs started up due to Loss of Off-site Power without malfunction


14:40:00 14:45:00 14:50:00 14:55:00 15:30:00 15:35:00 15:40:00 15:45:00 15:50:00 15:55:00 16:00:00 16:05:00

14:40:00 14:45:00 14:50:00 14:55:00 15:30:00 15:35:00 15:40:00 15:45:00 15:50:00 15:55:00 16:00:00 16:05:00

Unit 3

� EDG started up due to loss of off-site power, and the necessary power was secured

Transient Recorder (EDG)


� Seismic response analysis for representative safety related components shows that structural and functional integrity were maintained after the earthquake in unit 1 -3.

� Main steam line (unit 1-3)� RPV (unit 1-3)� PCV (unit 1-3)� core support structure (unit 1-3)� residual heat removal system (piping and pump) (unit 1-3)� control rod (unit 1-3)� Isolation Condenser (unit1)� Primary Loop Recirculation piping (unit1)� Suppression Chamber Saddle Support (unit1)� PCV Vent Line (unit1,2)� Core Spray System piping (unit2)� High Pressure Injection Line (unit3)� Emergency Diesel Generator (unit1-3)

Seismic Response Analysis


Dynamic analysis (Reactor Building)

Dynamic analysis (Reactor vessel Combined with Building)

Seismic force�Moment�Shear force�Axial force

曲

げ

せ

ん

断

は

り胴部局部

変形ばね

集中質量

Acceleration�Seismic intensity�Spectrum

Vessels

Pumps Pipe

0.05 0.5Period [s]

Acc

eler

atio

n [G

]

0.1 10

5

10

15

20

Shroud

Reactor Pressure Vessel

Seismic Response Analysis : Unit 1-3


FacilityEvaluation

PointItem

Unit 1 Unit 2 Unit 3

Calculation value

Evaluation criteria

Calculation value

Evaluation criteria

Calculation value

Evaluation criteria

RPVFoundation

VoltPrimary Stress

（（（（MPa））））93 222 29 222 50 222

Core SupportStructure

ShroudSupport

Primary Stress

（（（（MPa））））103 196 122 300 100 300

PCVDrywell

BodyPrimary Stress

（（（（MPa））））98 411 87 278 158 278

Main Steam Line System

PipingPrimary Stress

（（（（MPa））））269 374 208 360 151 378

Residual RemovalSystem

(Shut DownCooling System

for Unit 1)

PipingPrimary Stress

（（（（MPa））））228 414 87 315 269 363

Volt ofPump

Primary Stress

（（（（MPa））））8 127 45 185 42 185

Control RodFuel

Assembly

FlexibleVolume

（（（（mm））））

26.4 40 33.2 40 24.1 40

Seismic Response Analysis : Unit 1-3


Piping Model

PCV

PLR

RPV

Max. StressEvaluation Point Max. Stress

Evaluation Point

Max. StressEvaluation Point






Structure Evaluation Result

AnalyticalModel

CalculatedValue [MPa]

CriteriaValue [MPa] Margin

Isolation Condenser System

ValveHorizontal Vertical

CalculatedValue

CriteriaValue

CalculatedValue

CriteriaValue

Active Function Maintenance Evaluation

Seismic Response Analysis – Unit 1 : IC


Max. StressEvaluation

Point

PLR Piping Model (PLR-PD-1)

PCV

PLR

RPV

Primary Loop Recirculation System Diagram

Structural Integrity Evaluation Result

AnalyticalModel

CriteriaValue [MPa]

CalculatedValue[MPa]


Seismic Response Analysis – Unit 1 : PLR


S/C Seismic Intensity

Analytical ModelBracing Saddle Support

ReinforcedRing

Torus Body

Altitude Horizontal Vertical

R/B seismicResponse Analysis

Floor ResponseSpectrum, Intensity Set

S/C Support LoadingEvaluation by

Calculation Code

Evaluation for S/CSupport Class

Evaluation Flow

Zoom

Structural Drawing

●●●●：：：：Evaluation Point

Moment

EvaluationPoints

Support

StressCategory

Combination

CalculatedValue [Ratio]

CriteriaValue [Ratio] Note

Compression+Bend

Tension+Bend

Input Floor Response Spectrum(Horizontal)

Input Floor Response Spectrum(Vertical)

Ear

thqu

ake

Inte

nsity

Ear

thqu

ake

Inte

nsity

Proper Period

Proper Period

Seismic Response Analysis – Unit 1 : S/C Support

0.64

0.46

1.0

1.0


Vent pipes or tubes from the drywell directthe steam below the water level maintainedin the Suppression Chamber ( also knownas a torus or suppression pool), condensingthe steam, limiting the pressure ultimately

Vent Piping

Downcomer

Reactor Building

SuppressionChamber

Primary Containment Vessel

Structural Drawing

Evaluation Scope

Downcomer

Vent Piping

Suppression Chamber

Floor View

Zoom

: Evaluation Point

Vent Header


Ring Header

Section View

Vend Pipe => Vent Header => Steam fromDowncomer lead into S/C Water

Vent Header

Seismic Response Analysis – Unit 1 : PCV Vent


Unit 1 Seismic Response Analysis Result for Vent Line, etc (MPa））））


Joint of Vent Header andDowncomer

Evaluation Point

Vent Line

Downcomer body

Ring Header

CalculationValue

EvaluationCriteria Value Margin

16 230 14.73

122 432 3.54

120 346 2.88

75 411 5.48

Analytical Model for Vent Line


Evaluation Point

Calculation

Value

［［［［MPa］］］］

Criteria Value

［［［［MPa］］］］Margin

Vent Line 91 418 4.59

Joint of Vent Header and

Downcomer145 354 2.44

Downcomer body 12 236 19.66

Structural Drawing

<Analytical Model>

Vent Piping

Downcomer

SuppressionChamber

Vent Header


Downcomer

Vent Header

Vent Piping

: Evaluation Point



炉心スプレイ系概略系統図


Max. StressEvaluation PointPiping Model

RPVPCV

PCV

Core Spray System Diagram

Seismic Response Analysis Result

AnalyticalModel

CalculatedValue[MPa]


Seismic Response Analysis – Unit 2 : CS System


: Evaluation Scope

High Pressure Core Injection System Diagram

Seismic Response Analysis Result

AnalyticalModel

CalculatedValue [MPa]

CriteriaValue [MPa] Stress Ratio

No abnormalities such as pipe rupture were found in the HPCI room and the Torus Room which contains steam piping.


Max. StressEvaluation

Point


Analytical Model

Seismic Response Analysis – Unit 3 : HPCI


�Structural Integrity Evaluation Result

�Functional Operable Integrity Evaluation Result

Unit Components Evaluation PointCalculation

Value MPa））））

Criteria

Value MPa））））

Unit 1

Diesel Engine and Generator Holding Down Bolt 26 207

Fuel Service Tank Holding Down Bolt 18 207

Startup Air Tank Holding Down Bolt 19 207

Unit 2

Diesel Engine and Generator Foundation Bolt 38 146

Fuel Oil Tank Foundation Bolt 137 183

Startup Air Tank Shell Plate 91 268

Unit 3

Diesel Engine and Generator Foundation Bolt 56 146

Fuel Oil Tank Foundation Bolt 137 183

Startup Air Tank Shell Plate 91 288

Unit Components Evaluation Point

Horlizontal Vertical

Calculation

Value

Criteria

Value

Calculation

Value

Criteria

Value

Unit 1 Diesel Engine the center of gravity 0.60 1.1 0.35 1.0



The Japanese Diet report indicated the dame to the components. However, seismic impact to the components were not confirmed from this evaluation result.

Seismic Response Analysis – EDG


� Unit 5 Plant Walkdown was conducted as representative of unit 1-3 to estimate the seismic impact to unit 1-3.

� Seismic response analysis for Class S (Safety related) components was carried out based on observed record.

� As result of walkdown and seismic response analysis, no damage caused by the earthquake was identified on safety related components.

Unit 5 Walkdown / Seismic Response Analysis

�Unit 1-3 are inaccessible due to explosion and high radiation level.�Seismic acceleration observed at unit 5 was almost same as those of unit

1-3. (Unit 2-5 have same reactor type, BWR-4)


�Unit 5 is appropriate plant to estimate the seismic impact of unit 1-3 since seismic acceleration for unit 5 was almost same as unit 1-3 .


Observed Point(R/B Foundation)

Observed Point Max. Response Accelerationto Ss (GAL)Max. Acceleration (GAL)

NS EW UD NS EW UD

FukushimaDaiichi NPS

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

Comparison between Observed Record and Response toDesign Basis Earthquake Ground Motion (Ss)

Note）））） NS : North-South, EW : East-West, UD : Up-Down


�Seismic integrity for unit 5 is almost same as unit 1-3, since seismic design condition for unit 5 is almost same as unit 1-3. Unit 5 is appropriate plant to estimate the seismic impact of unit 1-3.



Unit 5 Walkdown

No equipment abnormality in terms of external appearance

Reactor Building Turbine Building

4th/3rd

Floor

2nd/1st

Floor

BasementFloor

PCV

RCIC Pump Flammablity Control System SLC Pump

MSIV HCU CUW Pump RCW Heat Exchanger

RPV SkirtPedestalSRVMSIV

Stabilizer (PCV) Stabilizer (RPV) PLR Riser PipingM/D-RFP

D/G

Moisture SeparatorPiping around

Moisture Separator

Instrument Compressor TCW Pump

2ndFloor

1stFloor

BasementFloor

HP TurbineThere are some cracks on the front standard foundation grout

T/D-RFP




Missing of insulation Gap of support

Damage to the small diameter drain pipe of the moisture separator

480V P/C

6.9kV M/CNo equipment abnormality in terms of external appearance

P/C6B-1 was inoperable because of inundation

Receiving electricity after installment of drain



4th

No equipment abnormality interms of external appearance

3rd

FPC Pump Although some signs of corrosion is found in both units, there are no equipment abnormalities in terms of external appearance


2nd1st


CRD PumpHPCIRHR PumpCore Spray Pump



No equipment abnormality in terms of external appearanceRetained water on the floorSigns of leakage on the wall penetration in the same area Retained water on the floor


Unit 5 Seismic Response Analysis�Evaluation Flow

Component SeismicResponse Analysis

Structure SeismicResponse Analysis

Calculating Seismic Force (Acc, Shear force, Moment,

etc)

PrimaryScreening

DetailAnalysis

AnalysisCompletion

Checkup withOn-Site Information

Calculating Max.Response Acc.

On Floor

Calculating FloorResponseSpectrum

PipingDetail Analysis

Without Screening

ResponseRatio is LessThan Margin

of Design

CalculationValue is LessThan Criteria

Value

NO

YES

NO

YES


Unit 5 Seismic Response Analysis�Structural Integrity Evaluation (Primary Screening)

�Confirm that ratio between seismic load on March 11th and design (response ratio) is less than design margin

�Conduct detail evaluation when response ratio is more than design margin

Seismic Load on March 11th

Design Seismic Loadα=

α (Response Ratio) < β (Design Margin)

[Response Ratio]

Evaluation Criteria Value

Calculation Valueβ=

[Design Margin]


FacilityEvaluation

PointR

PV

Rea

ctor

RP

VA

ttach

men

tS

yste

mStress

CategoryCalculation Criteria

Judgment

Support Skirt

Sleeves for control Rod

PLR Inlet Nozzle (N2)

Feed Water Nozzle (N4)

Stabilizer Bracket

Bearing Plate and &Attachment Bolt

Skirt

Sleeve

Nozzle Safe End

Nozzle Safe End

StabilizerAttachment

Bearing Plate

Gusseted Plate

Bearin Plate and &Attachment Bolt

Stabilizer (RPV-Shield Wall)

Stabilizer (Shield Wall-PCV) Connection Pipe

Envelope

AxialCompression

Envelope + Bend

Envelope

Envelope

Bend

Compression

Envelope + Bend

�Primary Screening Evaluation Result (1)

Unit 5 Seismic Response Analysis


FacilityEvaluation

Point

Rea

ctor

Rea

ctor

Cor

e S

truc

ture

Stress Category

Calculation CriteriaJudgment

Envelope + Bend

Envelope + Bend

Envelope + Bend

Envelope + Bend

Envelope + Bend

Envelope + Bend

Envelope

Envelope

Feed-water Sparger

Core Spray Sparger

Header

Header

Jet Pump

Core Shroud

Core Support Plate


In-Core Monitor Tube

Control Rod Guide Tube

Upper Grid Plate

Riser

SupportPlate

GridPlate

LowerTorso

Central OutsideSurface

(Longer Direction)

In-Core Monitor Tube



FacilityEvaluation

Point

Rea

ctor

Rea

ctor

Cor

e

Str

uctu

re

RP

V

Fou

ndat

ion

Stress Category


Envelope + Bend

Envelope + Bend

TensileForce

ShearForce


Core Spray Pipe

SLC Pipe

Support Structure(Foundation)

Support Structure (Top)

Pipe

Pipe

ReinforcingSteel

Joist Part



FacilityEvaluation

Point

SLC

CR

D

Inst

rum

ent a

nd C

ontr

ol

Equ

ipm

ent

Mea

sure

men

t In

stru

men

t

Stress Category


TensileForce

TensileForce

TensileForce

Hydraulic Control Unit

SLC Pump

SLC Storage Tank


Field Measurement Instrument

Bolt

AnchorBolt

Pump HoldingDown Bolt

Frame

MaximumPrinciple

Stress



FacilityEvaluation

PointR

HR

RC

IC

Rea

ctor

Coo

ling

Equ

ipm

ent

HP

CI

Cor

e S

pray

sy

stem

Stress Category


Combination

TensileForce

TensileForce

ShearForce

ShearForce

ShearForce

Primary Stress


RCIC Pump

RCIC-Turbine

HPCI Pump

Core Spray Pump

HPCI-Turbine

RHR Heat Exchanger

RHR Heat Strainer

Core Spray Strainer Primary Stress Pocket Sheet(Porous Plate)

Holding DownBolt

Turbine FixingGuide Block

Pump HoldingDown Bolt

FixingKnock Pin

FoundationBolt

Pocket Sheet(Porous Plate)

FoundationBolt



FacilityEvaluation

Point

PC

V

Prim

ary

Con

tain

men

t

Stress Category


Combination

ShearForce

Envelope + Bend

Envelope + Bend

Envelope + Bend

Envelope + Bend

Envelope

Compression


Dry Well

D/W Vent Nozzle

D/W Stabilizer

D/W Bottom Sheet

D/W Skirt

Vent Header

Hatch

Airlock

SandCushion

Insert PlateAttaching

WeldedPart

Beam SheetAttaching

Concrete

End Plate

Insert PlateAttaching

PersonnelAirlock Attaching



FacilityEvaluation

Point

Prim

ary

Con

tain

men

t

SG

TS

Rad

iatio

n C

ontr

ol

Equ

ipm

ent

Mea

sure

men

t In

stru

men

t P

CV

P

enet

ratio

nStress


Judgment

TensileForce

Combination

ShearForce

ShearForce

Bend

Primary Stress


SGTS VentilatingExhaust Equipment

Suppression ChamberSpray Header

Penetration (Sleeve)

Dec

ompr

essi

onE

quip

men

t

SGTS Train

PCV Radiation Monitor

Rector Building Radiation Monitor

HoldingDown Bolt

HoldingDown Bolt

Leg Rod

Bolt

Penetration

Bolt



FacilityEvaluation

PointStress


JudgmentF

HM

Fue

l Han

dlin

g E

quip

men

t

Fue

l Sto

rage

E

quip

men

t TensileForce

TensileForce


FHM Platform

Reactor Building Crane

Spent Fuel Storage Rack

Control Rod Storage Rack

Rack Foundation

Bolt

Rack HoldingDownBolt

( Seismic Class B Equipment )No falling accidents were found.

( Seismic Class B Equipment )No falling accidents were found.



FacilityEvaluation

Point

Rea

ctor

Rea

ctor

Cor

e

Str

uctu

reR

PV

Stress Category


TensileForce

ShearForce

Envelope

Envelope

�Detailed Evaluation (1)

Foundation Bolt

Core Shroud Support

Drier Housing

Shell Plate

ShroudSupport Leg

EarthquakeBlock

FoundationBolt

Cylindertorso



FacilityEvaluation

PointR

HR

PC

V

Prim

ary

Con

tain

men

tR

eact

or C

oolin

g

Equ

ipm

ent

Inst

rum

ent

and

Con

trol

E

quip

men

t

Mea

sure

men

t In

stru

men

t

Stress Category


TensileForce

Combination

ShearForce

ShearForce

Envelope + Bend

Envelope + Bend

Envelope

�Detailed Evaluation (2)

RHR Pump

D/W Bottom Sheet

Suppression Chamber

S/CAnti-seismic Support

S/CColumn Support

SRNMDry tube

LPRM

SupportRod

AnchorBolt

Anti-seismicSupport

Connection

Sheet PlateWelding Area

Motor HoldingDown Bolt

CoverTube

DryTube

Ratio to the criteria



評価対象設備評価対象設備評価対象設備評価対象設備評価部位評価部位評価部位評価部位応力分類応力分類応力分類応力分類

計算値計算値計算値計算値

（（（（MPa））））評価基準値評価基準値評価基準値評価基準値

（（（（MPa））））判定判定判定判定

配

管

配

管

配

管

配

管

主蒸気系主蒸気系主蒸気系主蒸気系

配管本体配管本体配管本体配管本体一次応力一次応力一次応力一次応力 244 417 ○○○○

サポートサポートサポートサポートスナッバスナッバスナッバスナッバ反力反力反力反力 40 kN 67 kN ○○○○

残留熱除去系残留熱除去系残留熱除去系残留熱除去系


サポートサポートサポートサポート一次応力一次応力一次応力一次応力 159* 245 ○○○○

原子炉冷却材再循環系原子炉冷却材再循環系原子炉冷却材再循環系原子炉冷却材再循環系



給水系給水系給水系給水系

配管本体配管本体配管本体配管本体一次応力一次応力一次応力一次応力 167* 363 ○○○○


FacilityEvaluation

Point

Main Steam system

RHR

PLR

FDW

Pip

ing

Stress Category

Calculation Criteria Judgment

Support

Support

Support

Support

Piping

Piping

Piping

Piping

Primary Stress

Primary Stress

Primary Stress

Primary Stress

Primary Stress

Primary Stress

Primary Stress

�Detailed Evaluation (3) Note ：：：：Underlined values are evaluation results for the design basis ground motion (Ss).

SnubberReaction Force

* Temporary calculated values for the design basis ground motion Ss exceeded criteria value. However, Detailed calculated values, which were based on the observed records, were below the criteria values.







配

管

配

管

配

管

配

管

原子炉冷却材浄化系原子炉冷却材浄化系原子炉冷却材浄化系原子炉冷却材浄化系


サポートサポートサポートサポート一次応力一次応力一次応力一次応力 160 245 ○○○○

放射性放射性放射性放射性ドレンドレンドレンドレン移送系移送系移送系移送系



ほうほうほうほう酸水注入系酸水注入系酸水注入系酸水注入系



原子炉隔離時冷却系原子炉隔離時冷却系原子炉隔離時冷却系原子炉隔離時冷却系



FacilityEvaluation

Point

RCIC

SLC

Radiation Drain

CUW (RWCU)

Pip

ing

Stress Category


Piping

Support

Support

Support

Support

Piping

Piping

Piping

Primary Stress

Primary Stress

Primary Stress

Primary Stress

Primary Stress

Primary Stress

Primary Stress

Primary Stress

�Detailed Evaluation (4)Note ：：：：Underlined values are evaluation results

for the design basis ground motion (Ss).








配

管

配

管

配

管

配

管

高圧注水系高圧注水系高圧注水系高圧注水系



炉心炉心炉心炉心スプレイスプレイスプレイスプレイ系系系系



燃料燃料燃料燃料プールプールプールプール冷却浄化系冷却浄化系冷却浄化系冷却浄化系



FacilityEvaluation

Point

Flammability Control System

Pip

ing

Stress Category


Core Spray system

HPCI

Piping

Piping

Piping

Support

Support

Support

Primary Stress

Primary Stress

Primary Stress

Primary Stress

Primary Stress

Primary Stress










配

管

配

管

配

管

配

管

可燃性可燃性可燃性可燃性ガスガスガスガス濃度制御系濃度制御系濃度制御系濃度制御系



不活性不活性不活性不活性ガスガスガスガス系系系系



残留熱除去海水系残留熱除去海水系残留熱除去海水系残留熱除去海水系



FacilityEvaluation

Point

Pip

ing

Atmospheric Control system

RHR Sea water system

Stress Category


Piping

Support

Piping

Support

Piping

Support

Primary Stress

Primary Stress

Primary Stress

Primary Stress

Primary Stress

Primary Stress







�Functional maintenance evaluation for active (1)

Calculated Value [G] Criteria Value [G] JudgementHorizontal Vertical Horizontal Vertical

Evaluation components

HCU (Scram Valve)

SLC Pump

RHR Pump

RCIC Pump

RCIC-Turbine

HPCI Pump

Core Spray Pump

HPCI-Turbine

SGTS Exhauster



�Functional maintenance evaluation for active (2)

Note ：：：：Underlined values are evaluation results for design basis ground motion (Ss).

Judgement

Calculated Value [G] Criteria Value [G]

Horizontal Vertical Horizontal Vertical

Evaluation components

Valve

Main Steam system (SRV)

Main Steam system (MSIV)

PLR

FDW

RHR

RHR Sea water system

CUW (RWCU)

RCIC

Core Spray system

Atmospheric Control system

FPC




�Seismic integrity for unit 1-3 was enough against the earthquake since the original DBE was conservatively decided.

�As the result of the visual inspection to the greatest extent possible, safety related components and even low seismic class components were almost completely unaffected by the damage caused by the earthquake.

�No evidence of damage for safety related componentsbased on the records of operation for unit 1-3 after the earthquake.

�Seismic response analysis result for unit 1-3 shows the functional integrity of safety related components.

�No damage was identified for safety related components of unit 5 which has the same type of reactors, based on the result of plant walkdown and seismic response analysis.

Summary


＜＜＜＜Conclusion＞＞＞＞� It is reasonable that the accident for unit 1-3 did not

depend on seismic cause but the tsunami-induced event.

＜＜＜＜Future＞＞＞＞� Further seismic response analysis based on the

seismic observed record for unit 1-3 will be continued.

Summary