fukushima up-date

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Copyright 2014 Tokyo Institute of Technology All Rights Reserved.

Tokyo Tech and Hitachi Nuclear Engineering Course in Malaysia (4th Term)

- Core Design and Plant Dynamics -

L1, Fukushima Ex-NPS up-date

September 22, First Period

Yoshiaki Himeno

Tokyo Institute of Technology

1

40 pages including cover

sheet and glossary


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Copyright 2014 Tokyo Institute of Technology All Rights Reserved.Tokyo Tech and Hitachi Nuclear Engineering Course in Malaysia (4th Term)2

1. Accident, Quick Review

2. Ex-NPS Contamination3. Environment Remediation4. Post accident Safety grade-up for

the safest

Contents


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Copyright 2014 Tokyo Institute of Technology All Rights Reserved.Tokyo Tech and Hitachi Nuclear Engineering Course in Malaysia (4th Term)

Rare cases where natural disasters threatened

reactor safetyFukushima Daiichi NPS, Japan,

Great tsunami, Severe Accident, March, 2011

Fort Calhoun NPS, USA,

Food but no accident, June 2011

Blayais NPS, France

Flood, 36 hours off-site power loss, December, 1999

3


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Among many, only Fukushima Daiichi NPS

suffered deep flooding

NISA, March 31, 2011

4

Onagawa: 14.8m / 13m

Fukushima#1: 10m / 15m

Tokai No2: 8m / 5.4m

NPS: site elevation / tsunami height


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nuclear reaction:stopped as

designed

loss of emergency power

diesels & battery disabled by flooding

loss of ultimate heat sink:

seawater pumps disabled

loss of off site

power, 4 lines

lost

Great earthquake and tsunami brought SBO & LOHS


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5 days after 3.11

No.1 NPP

14 hrs of no water supply

No.2 & No.3 NPPs

About6 hrs of no water supply

TEPCO, Oct. 11, 2011.

No.1 NPP No.3 NPP


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1. 6hrs, 3km, 5,800

2. 1hrs, 10km, 5,100

3. 3hrs, 20km, 177,500

95hrs

Completed

1.E-021.E-011.E+001.E+011.E+02

1.E+031.E+041.E+05

3/11 3/12 3/13 3/14 3/15 3/16 3/17

11:00, 3/15, 1F1

20

30km,Ordered to stay in house

Sv/h

Site

bou

ndary

radiation

level

To date, no health effects in any person as a result of radiation exposure.

Water

injection

by fire

engines

7

Made from TEPCO

released data of

3/28/2011, Y.Himeno.

Time, distance,number of evacuees

Evacuation during 4-NPP accidents

vent

H2 explosion


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the safest

Contents


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Land contamination-1

Precipitated along with Oou Mountains, Iitomi

Mountains, Echigo Mountains, Shimotuke

Mountains and Kantou Mountains

CsI and CsOH

are 9 times and 5

times heavier,

respectively,than air, so they

tend to stay near

surface.JAEAs Activities toward Environmental

Remediation in Fukushima, January 29th,

2013, by JAEA

Cs-134 & Cs-137 MEXT and JAEA, Feb. 10, 2012.


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Land contamination-2

JAEAs Activities toward Environmental Remediation in Fukushima,

January 29th, 2013, by JAEA

1.E-01

1.E+00

1.E+01

1.E+02

1.E+03

1.E+04

release,

104

Tera

Bq

Historical largerelease accidents

prepared from Windscale Accident 10 October 1957.John

Ainslie, Atomica, Chernobyl OECD/NEA 2002 Review,

JAEA-INS. NISA H23.4.12, et al.

Fkshm

Chernobyl

Fukushima


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Fukushima vs Chernobyl

Executive summary, assessment of radiological and health impact, 2002 update of Chernobyl, OECD/NEA. Health impact,

Chernobyl accident, Appendix, World Nuclear Assoc. Environmental consequences of the Chernobyl Accident and their remediation,

20 yrs of experience, UN Chernobyl Expert Group, Aug. 2005.

Fkshm Chrnbyl

Time of

large FP

release

10 days by

graphite fire.

No CV

Evacuation Started quickly. Started after

3 days

weather Snow Clear

Environ.

Radiation

monitoring

Systematically

conducted

unknown

Food

limitationImmediately Continued

drinking milk

for >3 days

Core opened

Core covered


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Residents exposure : Fukushima & Chernobyl

Chernobyl: Ten Years On, OECD/NA, 1996. Chernobyl, Health

Impact, WNA, Nov. 2009. Chernobyl, 2002 update, Ten Years

On, OECD/NEA. Kenmin Kenkou Chousa-shiryou, Fukushima-Pre.,

in Japanese H24.4.21. from those prepared by Y.Himeno,.

Chernobyl

1Infant thyroid (0-7 years old) : About 4,000

thyroid cancers. 15 death.

2External exposure: 3,000 people exposed

10,000 mSv.

3External exposure of people for 20 years inthe specially controlled areas.

4: External exposure of people for 20 years in

the contaminated areas.

Due to unaware of the accident for 3 days,

children stayed outside and infants

continued to drink contaminated milk.Fukushima

A: External exposure


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Cs137 is becoming dominant contributor to

every contaminations

Calculated based on the measured data by Hiroshima

Univ., Kyoto Univ. and Nihon Univ., on March 28, 2011.

I1318d, Cs1342y,

and Cs13730yCs134and Cs137


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Cs-137 transfer from soil to rice

Concentration in soil1

Concentration in white rice

1/1,000

rice is not easily contaminated

After 3.11, the government

prohibited planting of ricein the highly contaminated

areas on April 29, 2011.Japan has a long history of research

on radioactive contamination of rice

and wheat since 1960s.

Transfer and distribution of radioactive materials in

agricultural products, in Japanese, H. Tsukuba, Institute for

Environmental Sciences Japan, April 4, 2012


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Historical land contamination and

contaminations of rice and wheat

1.0E+00

1.0E+01

1.0E+02

1.0E+03

1.0E+04

1.0E+05

1955 1975 1995 2015

National Institute for Agro-Environmental Sciences, Japan, 2011.

Data of rice are from Pacific Coast Regions. Data of wheat are

average ones across Japan. Fukushima data are at Tsukuba.

Meteorological Research Institute , Japan, Dec. 2011.

Data presented are at Tokyo and Tsukuba.

Fukushima data are at Tsukuba and are tentative.

1Bq/kg=50Bq/m2

Fukushima

Chernobyl

rice ,

mBq/kg

Wheat,

mBq/kg Not exceeded the

past maximum .

Fukushimas

highly

contaminated

area: rice, 540-

1540 Bq/kg .

Tsukuba-Fukushima:

200 km

Historical Cs137on land Cs137in white rice and white wheat


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Will Cs-137 in contaminated soil be washed out by rain?

If so, farming lands and residential areas will be re-

contaminated by water from forests and mountains.

Doesnt Cs-137 in contaminated soil move toward deep in land?If so, underground water for drinking and for farmers will be

soon in danger.

To give those answers : experimental studies by many institutes

Conclusions

1. Cs-137 is quickly and tightly combined with soil.

2. Cs-137 doesnt move toward deep in land.

The 4thquestion


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Cs137contents in land surface before 3.11

- stayed within 20cm depth for more than 35 years or more -

nuclear tests in

atmosphere

between 1945-1996is 528:

US:215, USSR:

219, UK: 21,

France:50,

China:23.From Atomica.

Mongolia,

dry soil,

in 2003

Cs137: 1Bq =

3x10-13g,

Tsukuba,

forest,

in 1999

Aomori,

Uncultivated land,

in 2003


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Why Cs is strongly combined with

clay soil of granite main component?

0 100 200

2m

220m

20200m200

Absorbed Cs in soilkBq/kg

Particle

size

of

soil

Negatively charged soil absorbs

cation. Soil absorbs Cs+more

strongly than K+and NH3+ .

Decontamination of firming land, Ministry of Agriculture, Forestry

and Fisheries of Japan, Nov. 2011., K. Ishii, Regular Mtg of Atomic

Energy Commission, Japan, Sept. 6, 2011., Cs behavior in Soil,

Japan Society of Soil Science and Plant Nutrition, 2011.


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Contents of radioactive material in

food and their regulatory limits

Radioactive materials in foods and their influence to our health, inJapanese, Food Safety Commission of Japan, Jan. 2012.

New regulatory limits of radioactive material contents in foods, in

Japanese, Effective from Apr. 1, 2012, Ministry of Health, labor and welfare.

tested by local governments. Also self-

imposed tested by producers and sellers.

Before 3.11


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Copyright 2014 Tokyo Institute of Technology All Rights Reserved.Tokyo Tech and Hitachi Nuclear Engineering Course in Malaysia (4th Term) 21

Cs137in agricultural products across

East Japan after 8 months from 3.11

After 2

years

Cs-137 in

all

agricultural

products

came down

within the

regulatory

limit.

prepared from Radioactive materials contained in foods, in Japanese, Ministry of Agriculture, Forestry and Fisheries, Feb.2012.


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the safest

Contents


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First thing to do was to find out

decontamination methods for wide areas

from Cabinet Office, Ministry of Environment,

JAEA

Before 3.11: we had a lot of laboratory

and plant scale decontamination

experience.

After 3.11: decontamination for wide

open field are urgently needed.

Called for candidate technology from

industries, academia, and governmentsectors across the country. Then, those

selected were subjected to the

demonstration test named Pilot Project,

Nov. 2011- Mar. 2012.


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Government policy for those decontaminations

Principles set by ICRP Who is responsible for

decontamination?

100

mSv/y

Emergency situation:

Need emergency measures

To reduce


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Children first

top priority was decontamination of school

From Results of model demonstration test of decontamination,in Japanese, Cabinet Office, Ministry of Environment and JAEA,

March 26, 2012. Totani, JAEA, October 16, 2011

The most of Cs: within

5cm from the land surface

Many volunteers having

experience gathered &

helped those activities.

Cs reduction rate:

8095


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Decontamination of

road & farming land(Total area of contaminatedfirming land in Fukushima) =

22(area within TokyoYamanote Line)

From Cabinet Office, Ministry of Environment and JAEA,

March 26, 2012. Totani, JAEA, October 16, 2011

Farming land


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Decontamination of forest

From Forestry Agency, April, 2012.

Decontamination:remove leaves and litter,

prevention of surface soil

loss.

Cs flow from forest to farming land& residential area was a big threat.

Fortunately, monitoring showed Cs-

137 loss from forest was 0-0.5%.

leaves

litter

Evergreen:Cs137

continued

stay on

leaves

JAEA, 2014.

Could

be long

term

source


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After the pilot project,

decontamination expanded & accelerated

JAEAs Activities toward Environmental Remediation in

Fukushima, January 29th, 2013, by JAEA

Quick & Easy find out hot-spot by -ray

camera,

by Fukushima-Pref. & Ministr y of

Environment


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Decontamination:

current status as of October 2014

Summary of Pilot Project

reduced


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the safest

Contents


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Sequence of Fukushima accident

and lesson learned

anti-Tsunami measures

protected off-site & on-site power as well as

core cooling system to avoid core damage

System to prevent CV over-pressure in

order to prevent CV failure

System to reduce FPs releases into air

Nuclear Regulatory Authority of Japan, 2013


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New regulatory requirements


Political decision:

Make regulatory body independent


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Example of reinforced or newly

introduced safety measuresPreparedness for beyond DBA: L-4

& L-5 events; in defense in depth

becomes mandatory.

In the past, those were voluntarily

carried out by the plant owners.

Raise

embankment

Water proof

Alternative

onsite AC

power (powervehicle)

Protect pump

against flooding


To prevent SBO, LOHS


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Example of newly introduced measures

to prevent core damage

Protected off-site power

supply (redundant,

diversity, robustness, ).

Protected Ultimate Heat

Sink (protected seawater

pump,

).



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Example of newly installed measures to

prepare for severe accident

Spray to depressurize CV

& reduce FPs releases

To reduce

released FPs

into the

environment

Water injection

system to preventthermal failure of

CV by molten core

Nuclear Regulatory Authority ofJapan, 2013


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M9 earthquake of 3.11

validated seismic designOnagawa NPS, i.e., closest to the epicenter, experienced

the strongest ground shaking of any plants affected by the

M9 earthquake of 3.11and some flooding from the tsunami.

IAEA sent a team of experts to the 3-units Onagawa NPSafter the 3.11 on March 11, 2011.

They concluded the impact of the earthquake on the NPS

"remarkably undamaged".

Tokai No.2 was also in safe. (IAEA,Aug.10,2012)

Validated the seismic design of NPP.

NRA is further reevaluating the site specific design

basis earthquake and corresponding tsunami.Nuclear Emergency Response Headquarters ,

Government of Japan, June, 2011.

Onagawa- :130km,

Fukushima-200km,

Tokai- 240km.


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NPPs applied for relicense, as of April, 2014

Tomari #1, #2, #3

Application accepted July 2013.

Kashiwazaki-Kariwa #6, #7

Application accepted Sept. 2013

Hamaoka #4

Application accepted Feb. 2014

Ohi #3, #4


Shimane #2

Application accepted Dec. 2013.

Genkai #3, #4Application accepted July 2013.

Higashidori #2


Onagawa #2


Tokai #2

Application accepted May 2014.

Takahama #3, #4


Ikata #3


Sendai #1, #2Application accepted July 2013.

Preliminary approval: July 2014

Applied NPPs: 33% of total installed NPP

capacity of 46GWe in Japan

Sendais next stage: construction permit,

30-day technical public comment, &

regional approvals.

NRA,2014


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Glossary

40

ATWS: anticipated transient without

scrum BDBD: beyond design basis accident

CD: control rod

CV: containment vessel

DBA: design basis accident

DBEQ: design basis earthquake DBT: design basis tsunami

ECCS: Emergency Core Cooling

System

FA: fuel assembly

FPs: fission products LOCA: loss of coolant accident

LOHS: loss of heat sink accident

NPP: nuclear power plant

NPS: nuclear power station

NRA: Nuclear Regulatory Agency,

Japan SA: severe accident

3.11: Great East Japan Earthquake on

March 11, 2011.

SBO: station blackout, i.e., loss of

both off-site and on-site power

TMI: Three Mile Island NPP, USA,

that went into core melt accident

Ural Accident: Hydrogen explosion of

high level radioactive storage tank in

reprocessing plant in Ural, the former

Soviet Union. Windscale: British air cooled graphite

moderated small military reactor that

went into fuel melt accident.

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