a tepco nuclear engineer’s...

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

Fukushima Nuclear AccidentA TEPCO Nuclear Engineer’s Perspective

ASME—Forging a New NuclearSafety Construct Workshop

Washington, DCDecember 5th, 2012

Kenji TateiwaManager, Nuclear Power Programs

Tokyo Electric Power Company, Washington [email protected]

All Rights Reserved ©2012 Tokyo Electric Power Company, Inc. 2

Great East Japan Earthquake (GEJE)

http://archive.shinsai.yahoo.co.jp/

http://archive.shinsai.yahoo.co.jp/

http://archive.shinsai.yahoo.co.jp/Cruise Ship Stranded

Houses Swept Away

Largest earthquake/tsunami in recorded history of Japan20+ m tsunami run-up observed in

coast line spanning 200 km1st-ever case Gov’t Emergency

Disaster Response HQ was set up19,000 dead/missing


Impact of GEJE to TEPCO Facilities

Epicenter

52 GW

31 GW

Beforeearthquake

Shortly afterearthquake

Lost 40 % of power supply

capacityShutdown:

Nuclear power stations: 7 units Thermal power stations: 12 units Hydro power stations: 25 Substations: 8

Immediate Power outage: 4 million households(14% of TEPCO’s customer base)

Rolling blackout: 10 days in March 2011

Massive interruption of infrastructure (even in Tokyo area):

Public transportation Telecommunication Food/water supply


My Post-Accident Activities:International Communication

Translation of Press Releases (3/11/11@Tokyo-H/Q)

Photo by V.J.LUNA

Presentation to 15 Embassies in Tokyo (6/24/11@Delegation of EU to Japan)


My Post-Accident Activities:International Collaboration

IAEA Preliminary Mission (4/6/11@1F)


My Post-Accident Activities:International Collaboration (cont’d)

Preparation forIAEA Fact-Finding Mission(5/21/11@1F “Bedroom”)

IAEA Fact-Finding Mission(5/27/11@1F)

Mike Weightman(Head of UK-ONR)

Masao Yoshida(1F Plant Manager)


My Post-Accident Activities:International Collaboration (cont’d)

Discussion with INPO-Industry Support Team (8/19/11@2F)

“Nothing has been more important in my career than supporting TEPCO.”


Supervised operation wearing full-face mask.

Checked instrumentation in near-complete darkness.

Accident Response at 1F<Challenging Condition in Main Control Room>

Brought in heavy batteries to restore instrumentations.

Lack of:instrumentation, communication means, lighting, food, water, sleep, ...Increase in:radiation level, fatigue, fear, despair, ...


Accident Response at 1F<Containment Vessel Venting in Unit-1>

72AO

ボンベ

210MO ラプチャーディスク排気筒

1AO

ボンベ

閉

閉

83AO

閉

閉90AO

0.549MPabsで破壊

RPV

D/W

RPVRPV

D/W

IA

IA

D/W最高使用圧力0.528MPabs

ベント実施圧力0.954MPabs

電磁弁

電磁弁

213AO

Remote operation unavailable due to SBO.

MO

AO

AO

AO

AO

MO

Exhaust stack

Rupture disc

Six men formed 3 “suicide squads” to manually open 2 valves in highly-radioactive area.

Core damage already occurred by this time.(3/12 9:04-9:30).

Venting required to

avoid catastrophic

failure.


Accident Response at 1F<Water Injection Into Reactors by Fire Trucks>

inoperable

standby

Shallow Draft Quay

Sea

Valve Pit Valve Pit Valve Pit Valve Pit

Fire Cistern

Fire Cistern

Fire Cistern

Fire CisternFire

Cistern

Fire trucks played critical role in injecting water into reactors and spent fuel pools.

24 fire trucks deployed. Fire brigade operated fire trucks amidst

high radiation and successive explosions.

Status as of 3/14/11


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 7:13

RHR

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 Blackout

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

Water Injection: NOHeat Removal: NO

Water Injection: YESHeat Removal: NO

Water Injection: YESHeat Removal: YES


Voices from the Field

“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.”

“Radiation level in the main control room was increasing by 0.01 mSv every 3 seconds but I couldn’t leave—I felt this was the end of my life.”

“Unit 3 could explode anytime soon, but it was my turn to go to the main control room. I called my dad and asked him to take good care of my wife and kids should I die.”

Unit 1 Main Control Room

Torus Room

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