THE SITUATIONS OF EXTERNAL AND INTERNAL RADIATION EXPOSURE IN - - PowerPoint PPT Presentation

THE SITUATIONS OF EXTERNAL AND INTERNAL RADIATION EXPOSURE IN FUKUSHIMA Fukushima Senior High School

Koh OIKAWA, Ayane ANZAI, Tetsuri TAKAMI

• 1. The Fukushima Accident
• 2. Harmful Rumors

－Agriculture, Tourism, and Discrimination －How people in Fukushima feel

• 3. The External Radiation Exposure

The Internal Radiation Exposure

• 4. Conclusion

CONTENTS

Fukushima

Where is Fukushima ?

Where is Fukushima Daiichi Nuclear Power Plant ?

In Futaba Town

• 1. AFTER THE ACCIDENT

Personal dosimeter Environmental Air Dose Monitor

• 1. AFTER THE ACCIDENT
• 0.3

0.2 0.7 1.2 1.7 2.2 2.7 3.2 2011 2012 2013 2014

Environmental Dose (mSv)

YEAR

Coastal Area Normal

• 0.3

0.2 0.7 1.2 1.7 2.2 2.7 3.2 2011 2012 2013 2014

Environmental Dose(mSv)

YEAR

Northern area Normal

They haven’t gone back to normal. Environmental Radiation Dose in Fukushima

• 1. AFTER THE ACCIDENT

20000 40000 60000 80000 100000 120000 140000 160000 180000 2012.June 2013.July

Refugeees within Fukushima Refugees out of Fukushima 102180 95316

62038

53277

The number of Fukushima refugees has hardly decreased

2-1. Agriculture

① Peach

→ Although the shipment has returned, the price hasn’t returned.

• 2. HARMFUL RUMOR

2010 2011 2012 Yen/kg 441 167 335

100 200 300 400 500

Yen/kg

The price of peaches in Fukushima

• 2. HARMFUL RUMOR

2-1. Agriculture

② Rice

→The price in Fukushima is still below the average

because of the harmful rumor.

2011 2012 2013 Rice yen/kg 19900 18500 19500 17500 18000 18500 19000 19500 20000 20500

The price of rice in Fukushima

Yen/kg

2-2. Tourism

→Japanese tourists are not willing to visit Fukushima

rather than foreign tourists.

• 2. HARMFUL RUMOR

2010 2011 2012 Japanese tourists 2595824 2591298 2422640 Foreign tourists 83000 35000 55000

500000 1000000 1500000 2000000 2500000 3000000

The number of tourists

Foreign tourists Japanese tourists

Example of discrimination outside Fukushima

• Children were treated badly, so their parents decided to return to

Fukushima.

• People were required to hand in some reports of radiation inspection.
• Some people were refused to check-in hotels, take a taxi, or enter a

restaurant. One reason: People in general did not understand radiation well and were more afraid than necessary

2-3. Discrimination

• 2. HARMFUL RUMOR

• “We want to continue to eat local food actively.”
• The radiation standard for shipment of food for

school lunch is very strict: 10 Bq/kg

• cf. Food for market in Fukushima: 100 Bq/kg
• cf. in EU: 500 - 1250 Bq/kg

2-4. Thoughts of people in Fukushima

① Interview to school lunch center

• 2. HARMFUL RUMOR

Some say: "We are still doubtful.” However, most say: "We are not afraid of using food made in Fukushima." "We don't care about radiation dose." ② Interview to my classmates

• 2. HARMFUL RUMOR

2-4. Thoughts of people in Fukushima

Most people living in Fukushima do not worry about radiation so much.

External exposure is being exposed to radioactive substances

• utside our bodies.
• 3. The External and Internal

Radiation Exposure

Internal exposure is being exposed to radioactive substances inside our bodies. e.g.) eating, breathing

• 3. The External and Internal

Radiation Exposure

• Sv (Sievert)… A unit to express the extent of

biological effect on living bodies of radiation exposure.

• Bq (Becquerel)… A unit to express how much an
• bject has been contaminated.
• 3. The External and Internal

Radiation Exposure

You can convert Bq into Sv with effective dose coefficients (see the table below).

Isotope Half-life (year) Ingestion (Sv/Bq) Inhalation (Sv/Bq)

134Cs

2.06 1.9×10-8 2.0×10-8

137Cs

30.0 1.3×10-8 3.9×10-8

• 3. The External and Internal

Radiation Exposure

• Integrated dosimeter “GLASS BADGE”

3-1. The External Exposure

1 10 100

0～0.1 0.1～0.5 0.5～1.0 1.0～1.5 1.5～2.0 2.0～2.5 2.5～3.0

9 78 12 rate【％】

Measurement of radiation level with a dosimeter In 2011

Average value of the accumulated dose for three months : 0.26mSv in 2011. －0.13mSv Average value of the accumulated dose for three months : 0.14mSv in 2012. ・Cumulative dose of radiation has decreased nearly in half.

1 10 100 18 81 1 rate【％】

Measurement of radiation level with a dosimeter In 2012

3-1. The External Exposure

・90% of Fukushima residents were exposed to less than 0.5mSv over 3 months. ・This is less than 2.0mSv/year. ・The ICRP excess radiation limit is 20mSv/year. ・The global average of natural radiation is 2.4mSv/year. Fukushima residents were NOT exposed to large amounts

• f radiation.

3-1. The External Exposure

• Examination method… All meals, snacks, and

drinks from one day were measured together by using germanium semiconductor detector.

• Inspection period… Dec. 2nd, 2012~Feb. 9th, 2013
• Respondent to this survey… ordinary people

selected at random: 78 people

3-2. The Internal Exposure

Monitoring Investigation of Daily Meals

• Measured values are in 0.076～22Bq/(person･day).
• 4 people have been exposed to radiation over 3Bq/(person･day).
• Most people have been exposed radiation under 1Bq/(person･

day).

22

RESULTS

3-2. The Internal Exposure

Monitoring Investigation of Daily Meals: Result

64 7 3 4

1～2 2～3 3＜

Intake of radioactive cesium in daily meals

[Bq/person・day] [people]

23

RESULTS

Monitoring Investigation of Daily Meals: Result

3-2. The Internal Exposure

0.12 0.18 1

0.2 0.4 0.6 0.8 1 1.2

Result ICRP' food safety standard

40K

[mSv]

• Max.: 22Bq/day= 0.12mSv/year

<< Below ICRP’s safety standard: 1mSV/year

• cf. You have to eat about 70,000Bq for a year to get 1mSv.

<< Below the natural dose of 40K: 0.18mSv/year

The 2 types of investigations: the investigation with integrated dosimeters, and monitoring investigation of daily meals show:

We can clearly claim that Fukushima is SAFE.

• 4. Conclusion

Thank you for listening!