United Nations Scientific Committee on the Effects of Atomic Radiation

ATTACHMENT A-10

METHODOLOGY FOR ESTIMATING EXTERNALDOSES FROM THE PLUME AND INTERNALDOSES FROM INHALATION OF
RADIONUCLIDES IN THE PLUMEUNSCEAR 2020/2021 Report, Annex B, Levels and effects of radiation exposuredue to the accident at the Fukushima Daiichi Nuclear Power Station: implicationsof information published since the UNSCEAR 2013 Report
Content
This attachment describes the methodology used for assessing doses to the public from inhalationof, and external radiation from, radioactive material released to the atmosphere during theaccident at Fukushima Daiichi Nuclear Power Station (FDNPS).
Notes
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© United Nations, March 2022. All rights reserved, worldwide.
This publication has not been formally edited.

ANNEX B, ATTACHMENT A-10: METHODOLOGY FOR ESTIMATING EXTERNAL AND INTERNAL DOSES …

3

CONTENTS
I. INTRODUCTION .................................................................................................................. 5
II. METHODOLOGY FOR ESTIMATION OF EXTERNAL DOSE FROM
RADIOACTIVE PLUMES .................................................................................................... 5
A. Computational model ....................................................................................................... 6
1. Doses to evacuees ....................................................................................................... 6
2. Doses to residents ....................................................................................................... 6
B. Model parameters ............................................................................................................. 7
III. METHODOLOGY FOR ESTIMATION OF INTERNAL DOSE FROMINHALATION OF RADIONUCLIDES ............................................................................... 7
A. Computational model ....................................................................................................... 8
1. Doses to evacuees ....................................................................................................... 8
2. Doses to residents ....................................................................................................... 8
B. Model parameters ............................................................................................................. 9
IV. CONTRIBUTION OF SHORT-LIVED RADIONUCLIDES TO THE
INHALATION DOSE.......................................................................................................... 11
REFERENCES ........................................................................................................................... 13

ANNEX B, ATTACHMENT A-10: METHODOLOGY FOR ESTIMATING EXTERNAL AND INTERNAL DOSES …

I.

5INTRODUCTION

1.
This attachment describes the methodology used for assessing doses to the public frominhalation of, and external radiation from, radioactive material released to the atmosphere during
the accident at FDNPS. The estimates of effective, thyroid, red bone marrow, colon and breast
doses have been based on environmental measurements and realistic models and assumptions.
2.

The Committee focused on four groups of geographical areas of Japan:-

Group 1 included municipalities in Fukushima Prefecture where members of the public
were evacuated in the days to months after the accident;-Group 2 included all non-evacuated municipalities of Fukushima Prefecture;-

Group 3 included selected prefectures in eastern Japan that were neighbouring
Fukushima Prefecture (Ibaraki, Miyagi, Tochigi and Yamagata prefectures);-Group 4 included all of the remaining 42 prefectures of Japan.

3.
The age groups considered were the three standard age groups (1-year-old infant,10-year-old child and adult) defined by the International Commission of Radiological Protection(ICRP). Account has been taken of uncertainty in the estimated doses and variability between
individuals depending on their location, lifestyle and habits etc. (see attachment A-12).

II.

METHODOLOGY FOR ESTIMATION OF EXTERNAL DOSE FROM
RADIOACTIVE PLUMES

4.
Insufficient measurements of dose rates and concentrations of radionuclides in air wereavailable for the estimation of dose received over the first few days after the start of the release.
The concentrations in air were therefore obtained from the results of atmospheric transport,
dispersion and deposition models (ATDM). These modelling results were used either directly(for doses to evacuees) or in combination with the measurement data on the deposition densityof radionuclides (for doses to permanent residents) to estimate concentrations in air for the
purposes of assessing doses to the public (see attachment A-9 for further details). A semi-infinite
cloud model was used to estimate the doses from external exposure from the time-integrated
concentrations in the air.
5.
Terada et al. [Terada et al., 2020] did not provide estimates of the concentrations of 133Xein air, and the contribution of 133Xe has not been included in the Committee’s updated dose
estimates. The Committee has, however, carried out some scoping calculations to assess its
possible contribution to the estimated doses. Moriguchi et al. [Moriguchi et al., 2019] derived aratio of the air concentration of 133Xe to that of 137Cs of 800 from Nishihara et al. [Nishihara etal., 2012], and this ratio is broadly consistent with the ratio of the air concentration of 133Xe tothat of 131I derived from the few available measurements of 133Xe in air reported by Terasaka
et al. [Terasaka et al., 2016]. If a ratio of 800 is assumed, then including 133Xe would increase
the effective dose to adults from external exposure to the plume of airborne radioactive material
by about 30%. If account is also taken of the contribution of 133Xe to the effective dose frominhalation (to reflect its tissue solubility), then the effective dose from inhalation would increaseby less than 0.1%. As the effective dose from external exposure to radioactive material in the

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ANNEX B, ATTACHMENT A-10: METHODOLOGY FOR ESTIMATING EXTERNAL AND INTERNAL DOSES …

plume is generally only 1–3% or less of the effective dose from inhalation of radioactive material
in the plume, including the contribution of 133Xe would have increased the total effective dosefrom exposure to the plume by less than 1%. This contribution is small in comparison with theuncertainties in the dose estimates.
A.

Computational model1.

Doses to evacuees

6.
The dose 𝐸𝐸𝑖𝑖𝑐𝑐𝑐𝑐 from external exposure to radionuclides in the radioactive plume wasestimated from the modelled radionuclide concentrations in the surface air (as provided by the
ATDM model from [Terada et al., 2020] – see attachment A-9) using the following equation:𝑇𝑇

𝑐𝑐𝑐𝑐
𝑎𝑎𝑎𝑎𝑎𝑎 (𝑡𝑡)
𝐸𝐸𝑖𝑖𝑐𝑐𝑐𝑐 = 10−6 ∙ 𝑅𝑅𝑅𝑅𝑖𝑖𝑐𝑐𝑐𝑐 ∙ ∑𝑚𝑚 𝑒𝑒𝑚𝑚,𝑖𝑖∙ ∫0 𝑐𝑐𝑐𝑐 𝐶𝐶𝑚𝑚
∙ 𝑑𝑑𝑑𝑑 (mSv)

where:(A-10.1)

𝑐𝑐𝑐𝑐− 𝑒𝑒𝑚𝑚,𝑖𝑖
is the dose-rate conversion coefficient for a semi-infinite volume source in air equal
to the ratio of the dose rate for the representative person of population group, i, to uniform
activity concentration of radionuclide, m, in air (nSv/h per Bq/m3 or nGy/h per Bq/m3)(see table A-10.3);− 𝑅𝑅𝑅𝑅𝑖𝑖𝑐𝑐𝑐𝑐 is the aggregated dose reduction factor for external exposure from radionuclides inair (dimensionless); this aggregated reduction factor is calculated from sum of the productsof fj and pij, where fj is the ratio of dose rate from external exposure from the plume atlocation, j (e.g., outdoors, or inside houses or at workplaces) to the dose rate at an
undisturbed open field under an semi-infinite radioactive plume; pij is the fraction of timespent by the representative of population group, i, in the typical location, j;− 𝑇𝑇𝑐𝑐𝑐𝑐 is the time duration of human exposure from the passage of a radioactive plume overa site of interest (h);𝑎𝑎𝑎𝑎𝑎𝑎− 𝐶𝐶𝑚𝑚is the time-dependent concentration of radionuclide, m, in surface air (Bq/m3).

7.
This approach was applied to evacuees, where the time duration of exposure depended
on the evacuation scenario. Further details about the evacuation scenarios considered by theCommittee are presented in attachment A-11.
2.

Doses to residents

8.
For all other population groups, the time-integrated concentration in air was estimatedfrom measurements of the deposition density of radionuclides by scaling by the ratio of thedeposition density to the time-integrated air concentration estimated using ATDM (the “bulkdeposition velocity” see attachment A-9). The external dose 𝐸𝐸𝑖𝑖𝑐𝑐𝑐𝑐 from radionuclides in theradioactive plume was calculated from measurements of the deposition density of radionuclides
as follows:𝐴𝐴

𝑐𝑐𝑐𝑐
𝐸𝐸𝑖𝑖𝑐𝑐𝑐𝑐 = 2.8 ∙ 10−10 ∙ 𝑅𝑅𝑅𝑅𝑖𝑖𝑐𝑐𝑐𝑐 ∙ ∑𝑚𝑚 𝑚𝑚 ∙ 𝑒𝑒𝑚𝑚,𝑖𝑖
(mSv)
𝑉𝑉𝑚𝑚

(A-10.2)

ANNEX B, ATTACHMENT A-10: METHODOLOGY FOR ESTIMATING EXTERNAL AND INTERNAL DOSES …

7

where Am is the measured deposition density of radionuclide, m, on the ground (Bq/m2); Vm isthe “bulk deposition velocity” of radionuclide, m, estimated from ATDM (m/s), which is location
dependent; and the other symbols are the same as above.
B.

Model parameters

9.
The Committee used the latest ICRP Publication 144 [ICRP, 2020] to provide the dosecoefficients for air kerma, ambient dose equivalent and effective dose, as well as for equivalentorgan doses for six age groups and both sexes (only adults). Values of dose-rate conversion
coefficients for photon exposure from submersion in a radioactive plume and for the full list ofradionuclides considered in the Committee’s dose assessment are shown in table A-10.1.
Table A-10.1. Effective dose-rate conversion coefficients and absorbed dose-rate conversion
coefficients for the thyroid for photon exposure from submersion in a radioactive plume[ICRP, 2020]
Effective dose coefficient((nSv/h) per (Bq/m3))

Radionuclide

Thyroid dose coefficient((nGy/h) per (Bq/m3))

1 year10 years

Adult

1 year10 years

Adult (male)

131I

0.066

0.061

0.056

0.071

0.073

0.068

133I

0.109

0.100

0.094

0.111

0.114

0.108

132Te (+132I)

0.449

0.413

0.390

0.453

0.466

0.435

134Cs

0.279

0.256

0.242

0.283

0.289

0.272

137Cs (+137mBa)

0.105

0.092

0.087

0.101

0.104

0.098

10.
The durations of the passage of the main radioactive plumes were relatively short (a few
hours) and the contribution to dose from external exposure from the plumes was small comparedwith that from deposited radionuclides. As little information was available to the Committee
about the shielding effects of Japanese house types for external exposure from the plume, thesame dose reduction factor was assumed as for external exposure from the ground (seeattachments A-1 and A-4).
11.
Implicit in this approach is the simplifying assumption that the concentrations ofradionuclides in air were uniform over the volume of a plume from which photons can reach thepoint at which the dose was delivered. The Committee considered this assumption to bereasonable because the nearest population groups to the release point resided at least a few
kilometres away.

III. METHODOLOGY FOR ESTIMATION OF INTERNAL DOSE FROMINHALATION OF RADIONUCLIDES
12.
The assessment of dose from the inhalation of radionuclides in air was based on theconcentrations of radionuclides in air estimated using ATDM (see attachment A-9), either
directly or in combination with the measurement data on the deposition density of radionuclides,
the age-dependent breathing rates and the appropriate dose conversion coefficients (i.e., theradiation dose that results from breathing in a unit amount of a radionuclide) specific to a
Japanese population (see attachments A-2 and A-4).

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ANNEX B, ATTACHMENT A-10: METHODOLOGY FOR ESTIMATING EXTERNAL AND INTERNAL DOSES …

A.

Computational model1.

Doses to evacuees

13.
The dose 𝐸𝐸𝑖𝑖𝑖𝑖𝑖𝑖ℎ from the inhalation of airborne radionuclides was estimated on the basisof modelled radionuclide concentrations in the surface air (as provided by the ATDM modelfrom [Terada et al., 2020]):
𝑇𝑇

𝑖𝑖𝑖𝑖ℎ
𝑎𝑎𝑎𝑎𝑎𝑎 (𝑡𝑡)
𝐸𝐸𝑖𝑖𝑖𝑖𝑖𝑖ℎ = 103 ∙ 𝜈𝜈𝑖𝑖 ∙ 𝑅𝑅𝑅𝑅𝑖𝑖𝑖𝑖𝑖𝑖ℎ ∙ ∑𝑚𝑚 𝑒𝑒𝑚𝑚,𝑖𝑖∙ 𝑘𝑘𝑚𝑚 ∙ ∫0 𝑐𝑐𝑐𝑐 𝐶𝐶𝑚𝑚
∙ 𝑑𝑑𝑑𝑑 (mSv)

where:(A-10.3)− νi is the age-dependent breathing rate (m3/s);− 𝑅𝑅𝑅𝑅𝑖𝑖𝑖𝑖𝑖𝑖ℎ is the aggregated dose reduction factor for inhalation of radionuclides in the air(dimensionless); this aggregated reduction factor was calculated from the sum of the
products of fj and pij, where fj is the ratio of dose rate from internal exposure frominhalation of radionuclides from the plume at location j to the dose rate at an undisturbed
open field in the radioactive plume; pij is the fraction of time spent by the representativeof population group, i, in the typical location, j;𝑖𝑖𝑖𝑖ℎ− 𝑒𝑒𝑚𝑚,𝑖𝑖
is the dose conversion coefficient for the committed dose to the representative
person of population group, i, from the inhalation of unit amount (1 Bq) of radionuclide,m, under reference conditions (a default particle size of 1 μm and typical absorption type)(Sv/Bq);− 𝑘𝑘𝑚𝑚 is the factor accounting for particle size and absorption type for radionuclide, m, thatare different from those assumed under reference conditions (dimensionless);− 𝑇𝑇𝑐𝑐𝑐𝑐 is the time duration of inhalation from a radioactive plume passing over the site ofinterest (h);𝑎𝑎𝑎𝑎𝑎𝑎− 𝐶𝐶𝑚𝑚is the time-dependent concentration of radionuclide, m, in surface air (Bq/m3) as
provided by the ATDM model from Terada et al. [Terada et al., 2020]; for iodine isotopes
three different chemical forms were considered separately in the ATDM model as wellas in the dose assessment.

2.

Doses to residents

14.
The dose from the inhalation of radionuclides in the air was calculated frommeasurements of the deposition density of radionuclides as follows:
𝐴𝐴

𝑖𝑖𝑖𝑖ℎ
𝐸𝐸𝑖𝑖𝑖𝑖𝑖𝑖ℎ = 103 ∙ 𝜈𝜈𝑖𝑖 ∙ 𝑅𝑅𝑅𝑅𝑖𝑖𝑖𝑖𝑖𝑖ℎ ∙ ∑𝑚𝑚 𝑚𝑚 ∙ 𝑒𝑒𝑚𝑚,𝑖𝑖∙ 𝑘𝑘𝑚𝑚 (mSv)
𝑉𝑉𝑚𝑚(A-10.4)

where Am is the measured deposition density of radionuclide, m, on the ground (Bq/m2); Vm isthe “bulk deposition velocity” of radionuclide, m, estimated from ATDM (m/s), which is location
dependent; and the other symbols are the same as above.

ANNEX B, ATTACHMENT A-10: METHODOLOGY FOR ESTIMATING EXTERNAL AND INTERNAL DOSES …

B.

9Model parameters

15.
The Committee has used a new model to derive dose coefficients specific to the Japanese
population reflecting differences in their intakes of stable iodine and fractional thyroid uptake U(see attachment A-2). Dose coefficients were calculated for inhalation of various physico-chemical
forms of 131I, 132I, 133I and 132Te and three types of the diet: a typical Japanese diet (U=15%),
a kelp-rich diet (U=5%), and a Western pattern diet (with the reference value of U of about 30%)that is popular among some groups of the Japanese population. Dose coefficients were derived forabsorbed dose in the thyroid, red bone marrow, female breast and colon as well as for effective
dose, from inhalation of aerosols of Type F, activity median aerodynamic diameter(AMAD)=1 µm, and for methyl iodide and elemental iodine. The population-specific dosecoefficients used by the Committee can be found in attachment A-4 and are for people witha typical Japanese diet; values for effective dose and absorbed dose in the thyroid for inhalation of
131 132 133
I, I, I and 132Te are listed in table A-10.2.
Table A-10.2. Japan-specific dose coefficients for inhalation of 131I, 132I, 133I in three chemical
forms and of 132Te in aerosol form by members of the public with a dietary intake of stableiodine typical for Japan (U=15%), i.e., effective dose per exposure and thyroid absorbed dose
per exposureRadionuclide
131I

132I

133I

132Te

Radionuclide
form

Effective dose per exposure(Sv per (Bq·s/m3))

Thyroid absorbed dose per exposure(Gy per (Bq·s/m3))

1-year-old

10-year-old

Adult

1-year-old

10-year-old

Adult (male)

Aerosola

2.0 × 10-12

1.6 × 10-12

9.6 × 10-13

4.8 × 10-11

3.7 × 10-11

2.1 × 10-11

Methyl iodide

2.7 × 10-12

2.4 × 10-12

1.6 × 10-12

6.7 × 10-11

5.8 × 10-11

3.6 × 10-11

Elemental iodine

4.1 × 10-12

3.7 × 10-12

2.3 × 10-12

9.5 × 10-11

8.3 × 10-11

5.1 × 10-11

Aerosola

7.2 × 10-14

7.2 × 10-14

1.5 × 10-14

3.4 × 10-13

2.3 × 10-13

1.3 × 10-13

Methyl iodide

4.6 × 10-14

4.0 × 10-14

2.9 × 10-14

7.9 × 10-13

5.9 × 10-13

3.5 × 10-13

Elemental iodine

4.7 × 10-13

6.8 × 10-13

6.4 × 10-14

1.0 × 10-12

7.4 × 10-13

4.4 × 10-13

Aerosola

5.0 × 10-13

3.7 × 10-13

1.7 × 10-13

9.8 × 10-12

6.3 × 10-12

3.5 × 10-12

Methyl iodide

6.4 × 10-13

4.9 × 10-13

3.2 × 10-13

1.5 × 10-11

1.1 × 10-11

6.5 × 10-12

Elemental iodine

1.3 × 10-12

1.2 × 10-12

4.7 × 10-13

2.1 × 10-11

1.6 × 10-11

9.2 × 10-12

Aerosola

4.9 × 10-13

4.2 × 10-13

2.2 × 10-13

5.4 × 10-12

3.6 × 10-12

2.1 × 10-12

a.Type F, AMAD=1 µm.

16.
The values of the dose conversion coefficients for inhalation of 134Cs and 137Cs weretaken from ICRP Publication 71 [ICRP, 1995], see table A-10.3. These were based on genericanatomical and physiological human data for a reference person, as defined by ICRP, and assuch are not intended to be specific to inhabitants of any specific region.
Table A-10.3. Committed dose coefficients for inhalation of 134Cs and 137Cs by members of the
public [ICRP, 1995]

Radionuclide
134Cs
137Cs

Radionuclide
forma

Effective dose per exposure(Sv per (Bq·s/m3))

Thyroid absorbed dose per exposure(Gy per (Bq·s/m3))

1-year-old

10-year-old

Adult

1-year-old

10-year-old

Adult (male)

Aerosol

4.4 × 10-13

9.4 × 10-13

1.7 × 10-12

3.8 × 10-13

9.0 × 10-13

1.6 × 10-12

Aerosol

3.3 × 10-13

6.5 × 10-13

1.2 × 10-12

2.6 × 10-13

6.2 × 10-13

1.1 × 10-12

a.Type F, AMAD=1 µm.

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ANNEX B, ATTACHMENT A-10: METHODOLOGY FOR ESTIMATING EXTERNAL AND INTERNAL DOSES …

17.
Values of the age-dependent breathing rates, νi, on which the dose coefficients per unit
exposure in tables A-10.2 and A-10.3 were based are shown in table A-10.4, and were takenfrom ICRP Publication 66 [ICRP, 1994]. The inhalation rates applied are the average rates overa day from the ICRP model of the respiratory tract and include time spent sleeping, at home andat work, and hence they are suitable for someone exposed for 24 hours a day.
Table A-10.4. Age-dependent breathing rates, νi, from ICRP [ICRP, 1994]
Inhalation rate (m3/s)

Age group
Adult (outdoor worker)

2.92 × 10-4

Adult (indoor worker or pensioner)

2.57 × 10-4

10-year-old

1.77 × 10-4

1-year-old

6.02 × 10-5

18.
In the absence of any more specific information, the default particle size and absorption
types specified by ICRP [ICRP, 1995] were assumed, that is, km was taken as one.
19.
Hirouchi et al. [Hirouchi et al., 2018] have presented new data for the reduction factor(fj) of internal exposure to take account of the filtering of air inside buildings (i.e., the ratio of
the indoor to the outdoor cumulative radionuclide concentrations or doses), which has been
experimentally derived for Japanese houses. The reduction factors ranged from less than 0.1 toapproximately 1. In the UNSCEAR 2013 Report [UNSCEAR, 2014] no reduction to account forsuch filtering effect was assumed (i.e., reduction factor of 1 was assumed). The study of Hirouchi
et al. indicates that lower reduction factors are more realistic for Japanese houses (especially forpost-1992 buildings). The Committee has therefore used a reduction factor of 0.5 (with anuncertainty range of 0.1 to 0.95) in its updated assessment of internal doses from inhalation ofradionuclides when staying indoors, which allows for a more realistic estimation of doses frominhalation.
20.
The same values for pij, the fraction of time spent by the representative of population group,i, in the typical location, j, have been used as in the methodology for assessing external dose from
deposited radionuclides (see attachments A-1 and A-4). These are listed in table A-10.5.
Table A-10.5. Fraction of time (occupancy factors) spent in various locations by the reference
representative of the considered population groups
Occupancy factors for a population group
Type of location

Children

Adult worker

1-year-old

10-year-old

OutdoorIndoor

0.9

0.9

0.7

0.9

At home and others

0.7

0.7

0.7

0.6

At work, school, kindergarten, etc.

0.2

0.2

Outdoors, including:

0.1

0.1

0.3

0.1

Residential areas

0.1

0.1

0.2

0.1

Indoors, including:Unpaved surfaces

0.3

0.1

21.
The values of “bulk deposition velocity”, Vm, for radionuclide, m, were derived from the
ATDM calculations as the ratios of the modelled estimates of the deposition density to themodelled estimates of the time-integrated concentration in air (see attachment A-9).

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11

IV. CONTRIBUTION OF SHORT-LIVED RADIONUCLIDES TO THE
INHALATION DOSE
22.
This section presents an analysis of the contribution of short-lived radionuclides to thethyroid dose from inhalation of radioactive material released from FDNPS. The short-lived
radionuclides considered here include only 132Te (together with its daughter 132I, which istypically in secular equilibrium due to the much shorter half-life of 132I of 2.3 hours comparedto the half-life of 132Te of 3.2 days) and 133I; the contribution of all other shorter lived
radionuclides (e.g., 129Te, 129mTe, 131mTe, 135I, 136Cs) to the total dose from inhalation is small bycomparison (see e.g., [Ohba et al., 2017]).
23.
Table A-10.6 shows the estimated contribution of short-lived radionuclides to the thyroid
dose from inhalation for some locations in Fukushima Prefecture and Miyagi Prefecture. Medianvalues, 5th and 95th percentiles are presented, which have been derived from the results of allcells of the ATDM grid within a radius of about 6 km around the centre of each location(i.e., these statistical values have been derived from all ATDM results within an area of about
110 km2, corresponding to about 110 grid cells in the ATDM local model and about 13 in the
ATDM regional model).
24.
The results show that areas with relatively high contributions of short-lived radionuclides
to the inhalation doses are located mainly north-west of FDNPS (up to a distance of about 10 km,
e.g., in the municipality of Futaba). In this area the contribution of 132Te/132I and 133I together
can reach up to about 50% of the contribution of the dose from 131I.
25.
Another area with relatively high contributions of short-lived radionuclides is located in
the north-eastern part of Miyagi Prefecture (see location Tome in table A-10.6), where thecontribution of 132Te/132I and 133I together can reach up to about 40% of the dose from 131I
(although the total doses in this area are relatively low, especially if compared to doses in theeastern parts of the Fukushima Prefecture).
26.
In most other areas the contributions of short-lived radionuclides to the inhalation doses
are significantly lower, typically being between 0% and 20% of that from 131I, with most of thevalues in the lower part of this range. In Fukushima City for example, the median value of thecontribution of short-lived radionuclides is about 3%, and it is about 8% for Iwaki City.
27.
The differences in the contribution of short-lived radionuclides to the inhalation doses
can be explained by the contribution of different plumes to the time-integral of the concentrationof radionuclides in air: those areas with relatively high contributions of short-lived radionuclides
were mainly affected by the first plume emitted from FDNPS on the afternoon of 12 March 2011.
All later plumes – and thus in all areas which were mainly affected by these later plumes – hadsignificantly lower contributions from short-lived radionuclides relative to the first plume(i.e., the later plumes were emitted 2.5 to 10 days later than the first plume).
28.
The estimated contributions of short-lived radionuclides to inhalation doses are broadly
consistent with the findings of others. Ohba et al. [Ohba et al., 2020] estimated the contribution
to be 59% (relative to that of 131I) for the plume released on 12–13 March 2011, and 8% for theplumes released on 15–16 March 2011; Shinkarev et al. [Shinkarev et al., 2015] estimated thecontribution to be as great as 30–40% for the plume released on 12 March 2011.

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Table A-10.6. Contribution of short-lived radionuclides to the thyroid dose from inhalation(relative to the contribution of 131I)
Contribution of short-lived radionuclides to thyroid dose to 1-year-old infants relative to that from 131I
(132Te + 132I)/131I

Location

133I/131I(132Te + 132I + 133I)/131I

Median

5th %ile

95th %ile

Median

5th %ile

95th %ile

Median

5th %ile

95th %ile

Fukushima
City

0.01

0.01

0.02

0.01

0.01

0.02

0.03

0.02

0.04

Futaba

0.05

0.04

0.12

0.06

0.02

0.28

0.14

0.06

0.36

Iwaki City

0.06

0.05

0.10

0.02

0.01

0.07

0.08

0.07

0.16

Sendai

0.02

0.01

0.04

0.04

0.02

0.21

0.06

0.03

0.24

Tome

0.04

0.03

0.06

0.31

0.23

0.36

0.35

0.26

0.42

ANNEX B, ATTACHMENT A-10: METHODOLOGY FOR ESTIMATING EXTERNAL AND INTERNAL DOSES …

13

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