Radiation Dose Statistics for Nuclear Workers in FY 2020
Radiation Dose Registration Center

1. Publication of radiation dose statistics
The Radiation Dose Registration Center (RADREC) of the Radiation Effects Association assigns a
unique registration number for each worker engaged in radiation works at nuclear power plants andnuclear facilities, and these radiation doses are centrally managed by the “Radiation Dose Registration
System for Nuclear Workers” (hereinafter refered to as “Nuclear Registration System”). Therefore,
even if the worker move from one nuclear facility to other facilities to engage in other radiation work,
the Nuclear Registration System enables previous radiation doses of each worker at all work sites
accurately.
Using the registered data, the RADREC publishes the statistics for fiscal year (FY, April-March) 2020
that represent the management status of radiation doses for the workers engaged in radiation workat the nuclear sites.
Since the contributions of radiation doses due to decommissioning of Fukushima-Daiichi Nuclear
Power Plant operated by Tokyo Electric Power Company was significantly large, radiation management
status of the other facilities under normal operation are difficult to understand. Therefore, thestatistics excluding Fukushima-Daiichi Power Plant are also published.
As the radiation doses for emergency works due to the accident at Fukushima-Daiichi Nuclear Power
Plant after the Great East Japan Earthquake which occurred on March 11, 2011 were not registeredin FY 2016, the dose statistics of emergency workers since FY 2017 is not published.
2. List of nuclear licensees registered in Nuclear Registration System
The statistical data were based on the radiation doses registered in Nuclear Registration System bythe following nuclear licensees. Names of the work sites are shown in parentheses.
(1) Japan Atomic Energy Agency (Nuclear Science Research Institute, Nuclear Fuel Cycle EngineeringLabs, Oarai, Tono, Ningyo-toge, Fugen, Monju, Mutsu)(2) Japan Nuclear Fuel Ltd. (Enrichment and Disposal Plants, Reprocessing Plant)(3) Hokkaido Electric Power Co., Inc. (Tomari)(4) Tohoku Electric Power Co., Inc. (Onagawa, Higashidori)(5) Tokyo Electric Power Co.Holdings, Inc. (Fukushima-Daiichi, Fukushima-Daini, Kashiwazaki-Kariｗa)(6) Chubu Electric Power Co., Inc. (Hamaoka)(7) Hokuriku Electric Power Co. （Shika）(8) The Kansai Electric Power Co., Inc. （Mihama, Takahama, Ohi）
(9) The Chugoku Electric Power Co., Inc. (Shimane)1(10) Shikoku Electric Power Co., Inc. （Ikata）(11) Kyushu Electric Power Co., Inc. (Genkai Sendai）(12) The Japan Atomic power Company (Tokai, Tokai No2, Tsuruga)(13) Nuclear Fuel Industries, Ltd. (Kumatori, Tokai)(14) Sumitomo Metal Mining Co., Ltd. (Tokai)(15) Global Nuclear Fuel Japan Co., Ltd. (Yokosuka)(16) Mitsubishi Nuclear Fuel (Tokai)(17) JCO Co., Ltd. (Tokai)
3. Data compilation method
The statistical data are based on the radiation doses of the workers engaged in radiation work of thenuclear licensees that have registered in the Nuclear Registration System operated by the RADREC.
(1) These statistical data are based on registered data provided by the nuclear licensees as of June29, 2021(2) The doses compiled are the effective doses, sum of external and internal exposure.
(3) “Maximum dose,” “collective dose,” “average dose,” and “%” were rounded to one decimal place.
Some discrepancy which total percent values are other than 100% may be caused by thisprocedure.
(4) The age of the workers were based on the time of March 31, 2021.
(5) The “Total number” of radiation workers were compiled based on distinct individuals, so thatworkers who worked at more than one nuclear site were counted as one.
【Dose Limits for radiation workers】
The statutory dose limits for radiation workers is 100 millisieverts (mSv) over five years and 50 mSv
in one year, the dose limit for female workers, excluding those who indicate no pregnancy and those
who are pregnant, is 5 mSv per 3 months with the dose limit above. Five-year period refers to thestatutory period that started on April 1, 2001 and has been renewed every subsequent five years.
[Definition of terminology](1) Radiation Worker：Worker who is designated by nuclear licensees as a radiation worker based on
the “Law for the Regulation of Nuclear Source Material, Nuclear Fuel Material, and Reactors“whose core occupation is in radiation control areas, excluding people who enter radiation control
areas occasionally.
(2) Exposure doses：Exposure doses of workers engaged in nuclear facilities registered in RADREC
are compiled as fiscal year data.
(3) Five-year exposure doses：Exposure doses accumulated in the statutory five-year period tocontrol long-term dose limit. The first period started on April 1, 2001, with exposure doses
accumulating every subsequent five years.
(4) Number of work sites in a year： Number of work sites in a year means the number of nuclear
sites where workers were engaged in radiation work during the fiscal year when the statistical data2were compiled. The total number of work sites in FY 2020 is 34. Even if the worker was engaged inradiation work at one nuclear site in several times in a year, that counted as one work site.
(5) Number of work sites in five years：Number of work sites in five years means the number ofnuclear sites where workers were engaged in radiation works during the period of statistical datacompilation (FY 2016 and 2020).
List of dose statistics
1. Dose Distribution of Workers by Age ｛FY 2020｝(Table)
2. Dose Distribution of Workers by Age ｛FY 2020｝(Figure)
3. Dose Distribution of Workers by Age ｛FY 2020｝(Excluding the Data for Fukushima Daiichi Nuclear
Power Plant) (Figure)
4. Dose Distribution of Workers by Age ｛FY 2020｝(Excluding the data for Fukushima Daiichi NuclearPower Plant) (Table)
5. Annual Trends of Numbers of Workers by Age｛FY 2016-2020｝ (Figure)
6. Annual Trends of Numbers of Workers by Dose Range｛FY 2016-2020｝ (Figure)
7. Dose Distribution of Workers by Gender ｛FY 2020｝ (Table)
8. Dose Distribution of Workers by Number of Work Sites ｛FY 2020｝ (Table)
9. Ratio of Number of Workers by Number of Work Sites ｛FY 2020｝ (Figure)
10. Annual Trends of Ratio of Workers by Number of Work Sites {FY 2016-2020｝ (Figure)
11. Dose Distribution of Workers by Number of Work Sites ｛FY 2020｝(Excluding the Data for
Fukushima Daiichi Nuclear Power Plant）(Table)
12. Dose Distribution of Workers by Number of Work Sites ｛FY 2020｝（Excluding the Data for
Fukushima Daiichi Nuclear Power Plant)(Figure)
13. Transient Dose Distribution of Workers by Number of Work Sites in Latest five Years ｛FY 20162020｝(Table)

31．Dose Distribution of Workers by Age {FY 2020}
Number of workers

DoseDose(mSv)
AgeDose≤0.１

0.1＜Ｄｏｓｅ≤11＜Ｄｏｓｅ≤22＜Ｄｏｓｅ≤55＜Ｄｏｓｅ≤1010＜Ｄｏｓｅ≤1515＜Ｄｏｓｅ≤20

Total № of workers

20＜ＤｏｓｅCollective

dose

MeanMax(％)（person・mSv） （mSv）

（mSv）

18～19

408

45

11

11

2

000

477

(0.7)

85.3

0.2

9.7

20～24

2,947

514

97

117

57

24

7

0

3,763

(5.9)

1,575.0

0.4

17.8

25～29

5,330

798

204

218

101

63

13

0

6,727

(10.6)

3,096.4

0.5

18.7

30～34

5,277

817

264

217

123

88

33

0

6,819

(10.7)

3,994.2

0.6

18.7

35～39

5,141

815

251

255

128

86

31

06,707(10.5)

4,073.3

0.6

19.3

40～44

5,840

907

287

300

158

106

38

0

7,636

(12.0)

4,880.0

0.6

19.3

45～49

7,173

1,058

293

309

184

111

36

0

9,164

(14.4)

5,207.5

0.6

19.3

50～54

6,069

877

288

280

151

89

46

0

7,800

(12.2)

4,709.2

0.6

19.1

55～59

5,709

820

245

262

112

78

39

0

7,265

(11.4)

4,005.3

0.6

19.3

60～64

3,879

537

165

171

81

41

19

0

4,893

(7.7)

2,460.2

0.5

19.0

65～69

1,557

231

50

51

18

25

110

1,943

(3.1)

978.7

0.5

18.7

70以上

413

501491320492(0.8)

150.3

0.3

18.8

Total № ofworkers

49,743(78.1)

7,469(11.7)

2,169(3.4)

2,200(3.5)

1,116(1.8)

714(1.1)275(0.4)0(0.0)－－－

7,007.9 8,101.1 8,759.9 4,628.7

0.0

35,215.4

0.6

19.3

(％）

CollectiveDose(person・mSv）

340.5 3,222.6 3,154.9

63,686 (100.0)－［Notes］
・ How to read the numbers in table above:The number "204" in the box for the age row of "25～29" and the dose column of "1<Dose≤2" means that there were 204workers between age 25 and 29 inclusive whose radiation doses were in the range of greater than 1 and less than or equal to 2 millisieverts in FY 2020.
・The workers' ages are calculated as of March 31, 2021.

2．Dose Distribution of Workers by Age {FY 2020}
10,00010＜Dose

9,000

5＜Dose≤10

Number of workers

8,000

2＜Dose≤51＜Dose≤2

7,0000.1＜Dose≤1
Dose≤0.１

6,000
5,000
4,000
3,000
2,000
1,0000Age＊ This figure is based on the data in the Table １ "Dose Distributin of Workers byAge {FY 2020}".

3．Dose Distribution of Workers by Age{FY 2020}(Excluding the Data for Fukushim-Daiichi Nuclear Power Plant)
Number of workers

Dose

Dose(mSv)
Age

Dose≤0.１0.1＜Ｄｏｓｅ≤11＜Ｄｏｓｅ≤22＜Ｄｏｓｅ≤55＜Ｄｏｓｅ≤1010＜Ｄｏｓｅ≤1515＜Ｄｏｓｅ≤20

Total № of workers

20＜Ｄｏｓｅ(％)

Collective
dose

MeanMax（person・mSv） （mSv）（mSv）

18～19407

41

65

1

000460(0.8)

53.7 0.1

9.7

20～24

2,917

419

60

62

16

600

3,480(6.4)

655.2 0.2

13.4

25～29

5,164609

114

98

28

1000

6,023(11.1)

1,053.3 0.2

14.8

30～34

5,110

594

139

86

26

5

1

0

5,961(10.9)

1,021.1 0.2

15.4

35～39

4,895

583

120

103

21

2

2

0

5,726(10.5)

958.7 0.2

17.2

40～44

5,595

637

138

125

21

6

1

0

6,523

(12.0)

1,107.4 0.2

15.6

45～49

6,725

719

131

123

22

7

0

0

7,727

(14.2)

1,145.4 0.1

13.2

50～54

5,613

530

118

86

27

3

0

0

6,377(11.7)

918.5 0.1

14.7

55～59

5,337

511

84

71

14

2

10

6,020(11.1)

702.5 0.1

16.8

60～64

3,650

334

61

40

123

004,100(7.5)

504.9 0.1

14.1

65～69

1,437

151

25

195

100

1,638(3.0)

218.1 0.1

12.2

70以上

384

33

71

1000426(0.8)

33.7 0.1

7.4

Total № ofworkers

47,234

5,161

1,003

819

194

45

50(％）

(86.7)

(9.5)

(1.8)

(1.5)

(0.4)

(0.1)

(0.0)

(0.0)

2,532.2 1,350.1

539.2

80.7

0.0

Collective Dose(person・mSv）

285.9 2,113.6 1,470.8

54,461 (100.0)－－－－

8,372.5

0.2

17.2［Notes］
・ This table was compiled by excluding the data for Fukushima-Daiichi Nuclear Power Plant. The exposure dose data of workers at Fukushima Daiichi Nuclear
Power Plant are shown in website of Tokyo Electric Power Company Holdings,lnc.
・ How to read the numbers in table above:The number "114" in the box for the age row of "25～29" and the dose column of "1<Dose≤2" means that there were
114 workers between age 25 and 29 inclusive whose radiation doses were in the range of greater than 1 and less than or equal to 2 millisieverts in FY
2020.
・ The workers' ages are calculated as of March 31,2021.

4．Dose Distribution of Workers by Age{FY 2020}(Excluding the Data for Fukushima-Daiichi Nuclear Power Plant)
9,000
10＜Dose8,000

5＜Dose≤102＜Dose≤57,000
Number of workers

1＜Dose≤2

6,000

0.1＜Dose≤1
Dose≤0.１

5,000
4,000
3,000
2,000
1,0000Age＊ This figure is based on the data in the Table 5 "Dose Distribution ofWorkers by Age{FY 2020}(Excluding the data for Fukushima-Daiichi NuclearPower Plant)".

5．Annual Trends of Number of Workers by Age{FY 2016－2020}
11,000fiscal year

10,0002016

Number of workers

9,000

2017

8,000

2018

7,000

2019

6,000

2020

5,000
4,000
3,000
2,000
1,0000Age＊ This figure is based on the data in the Table １ "Dose Distributin of Workersby Age {FY 2020}" and those of the latest four years {FY 2016－2019}.

6.Annual Trends of Number of Workers by Dose Range{FY 2016－2020}
12,00065,00060,00011,000fiscal year

55,00010,0002016

9,000
50,0002017

Number of workers

8,000

2018

7,000

2019

6,000

2020

5,000
4,000
3,000
2,000
1,000
0Dose（mSv)＊ This figure is based on the data in the Table 1 "Dose Distributin of Workers by Age{FY 2020}"and those of the latest four years {FY 2016－2019}.

7．Dose Distribution of Workers by Gender{FY 2020}
Collective dose
(person･mSv)

FemaleTotal № ofworkers

(％）

(％）

(％）

(％）

48,872(77.8)
7,438(11.8)
2,167(3.5)
2,200(3.5)
1,115(1.8)
714
(1.1)
275(0.4)0(0.0)
62,781(100.0)871(96.2)31(3.4)2(0.2)
0(0.0)
1(0.1)
0(0.0)
0(0.0)
0(0.0)
905(100.0)

49,743(78.1)
7,469(11.7)
2,169(3.4)
2,200(3.5)
1,116(1.8)
714(1.1)275(0.4)0(0.0)
63,686(100.0)

340.5
(1.0)
3,222.6(9.2)
3,154.9(9.0)
7,007.9(19.9)
8,101.1(23.0)
8,759.9(24.9)
4,628.7(13.1)
0.0(0.0)

98.6

1.4

100.0－

35,192.0

23.4－

35,215.6(100.0)Mean dose
（mSv）

0.6

0.0

0.6

－

Max dose
(mSv）

19.3

6.5

19.3

－

GenderDose(mSv)

Dose ≤ 0.1
0.1< dose ≤ 1
1< dose ≤ 2
2< dose ≤ 5
5< dose ≤ 1010< Dose ≤15
15< Dose ≤20
20< Dose
Total № of workers（％）
Total № of workers
Ratio of man and famel(％）
Collective dose(person・mSv）

Male－［Notes］

・ How to read the numbers in table above：The number "2,167 " inthe box of the dose row "1 < Dose ≤ 2" and the "Male" column
means that there were 2,167 man workers whose radiation doses
were in the range of greater than 1 and less than or equal to 2
millisieverts in FY 2020.

8．Dose Distribution of Workers by Number of Work Sites{FY 2020}№ of Work
sites

Number of workers
123456Total № of workersor more(%)

Dose ≤ 0.145,066

3,952556130

23

1649,743(78.1)

0.1 < Dose ≤ 15,810

1,31227157

18

17,469(11.7)

1 < Dose ≤ 21,679355

102

26

702,169(3.4)

2 < Dose ≤ 5

1,708

357

101

26

7

12,200(3.5)

5 < Dose ≤ 10904

150

42

14

5

11,116(1.8)

10 < Dose ≤ 15632

70

8

1

30714(1.1)

15 < Dose ≤ 20

265

8

1

100275(0.4)

00000

00(0.0)56,064(88.1)

6,204(9.7)

1,081(1.7)

255(0.4)63(0.1)19(0.0)63,686(100.0)

0.5

0.7

0.9

1.1

1.7

0.6

0.6

Dose(mSv)

20 < Dose
Total № of workers（％）
Mean dose（mSv）［Notes］
・ How to read the numbers in table above：The number "23" in the box for the dose rowof "Dose≤ 0.1" and the № of work sites of "5" column means that there were 23workers who were engaged in five work sites and whoes radiation doses were less than
5 millisievert in FY 2020.

9．Ratio of Number of Workers by Number ofWork Sites{FY 2020}
100%
90%

20 ＜Dose
15 ＜Dose≤ 20
10 ＜Dose≤ 155 ＜Dose≤ 102 ＜Dose≤ 51 ＜Dose≤ 20.1 ＜Dose≤ 1Dose≤ 0.1

Ratio of number of workers

80%
70%
60%
50%
40%
30%20%
10%0%
１２３４５

Numbers of engaged nuclear sites

６or more＊ This figure is based on the data in the Table 8 "Dose Distribution ofWorkers by Number of Work Sites {FY 2020}".

10．Annual Trends of Ratio of Workers by Numberof Work Sites {FY 2016-2020}
100%
90%

４sites more３sites２sites１site

Ratio of number of workers

80%
70%
60%
50%
40%
30%
20%
10%
0%
20162017201820192020Fiscal year

＊ This figure is based on the data in the Table 8 "DoseDistribution of Workers by Number of Work Sites {FY 2020}" andthose of the latest four years {FY 2016－2019}.

11．Dose Distribution of Workers by Number of Work Sites {FY 2020}(Excluding the Data for Fukushima-Daiichi Nuclear Power Plant)
Number of workers№ of Worksites

123456

Total № of workers(%)

or moreDose(mSv)

42,788

3,756

527

128

20

15 47,234 (86.7)

3,767

1,086

237

54

16

15,161(9.5)

1 < Dose ≤ 2618

262

92

25

60

1,003(1.8)

2 < Dose ≤ 5454246

87247

1819(1.5)

5 < Dose ≤ 10846827951194(0.4)

10 < Dose ≤ 152810313045(0.1)

15 < Dose ≤ 20

1301

005(0.0)

20 < Dose

0000

000(0.0)

47,740(87.7)

5,431(10.0)973(1.8)242(0.4)

57(0.1)18(0.0)54,461(100.0)

0.1

0.4

0.8

0.9

1.9

0.6

0.2

Dose ≤ 0.1
0.1 < Dose ≤ 1

Total № of workers（％）
Mean dose（mSv）［表の見方］
・This table was compiled by excluding the data for Fukushima-Daiichi Nuclear Power Plant. The
dose data of workers at Fukushima-Daiichi Nuclear Power Plant are shown in HP of Tokyo
Electric Power Company Holdings,lnc.

・How to read the numbers in table above：The number "20" in the box for the dose row of "Dose≤ 0.1" and the № of work sites of "5" column means that there were 20 workers who wereengaged in five nuclear sites and whoes radiation doses were less than 5 millisievert in FY
2020.

12．Dose Distribution of Workers by Numberof Work Sites {FY 2020}(Excluding the Data for Fukushima-Daiichi Nuclear Power Plant)
100%90%20 ＜Dose15 ＜Dose≤ 2010 ＜Dose≤ 155 ＜Dose≤ 102 ＜Dose≤ 51 ＜Dose≤ 20.1 ＜Dose≤ 1Dose≤ 0.1

Ratio of number of workers

80%
70%
60%
50%
40%
30%
20%
10%
0%

１２３４５

Numbers of engaged nuclear facilities

６or more＊ This figure is based on the data in the Table 11 "Dose Distribution ofWorkers by Number of Work Sites {FY 2020}".

13．Transient Dose Distribution of Workers by Number of Work Sites
in Latest five Years {FY 2016-2020}
No. of work sites
in five years

Number of workers

12345678

Dose(mSv)

or moreTotal № of workers(%)

Dose ≤ 1

71,094

12,160

3,193

1,101

428

161

65

70

88,272 (80.5)

1 < Dose ≤ 5

7,008

2,508

1,012

500

236

117

32

19

11,432 (10.4)

5 < Dose ≤ 10

2,537

821

338

173

91

46

21

104,037(3.7)

10 < Dose ≤ 15

1,284381

147

83

44

26

77

1,979(1.8)

15 < Dose ≤ 20893

232

87

47

24

1294

1,308(1.2)

20 < Dose ≤ 25508

149

54

219633753(0.7)

25 < Dose ≤ 30373105

38

175520545(0.5)

30 < Dose ≤ 40

44911838136411630(0.6)

40 < Dose ≤ 50

22782

2282020343(0.3)

50 < Dose ≤ 60

154

35

720000198(0.2)

60 < Dose ≤ 70

83

20400000107(0.1)

70 < Dose ≤ 80

781330000094(0.1)

80 < Dose ≤ 90

12000000012(0.0)

90 < Dose ≤ 100

000000000(0.0)

100< Dose

000000000(0.0)

84,700(77.2)

16,624(15.2)

4,943
(4.5)

1,965(1.8)

845(0.8)377(0.3)

142(0.1)

114(0.1)

109,710(100.0)

1.6

2.4

2.9

3.2

3.4

4.3

5.4

3.3

1.9

Total no. of workers（％）
Mean dose（mSv)［Notes］
・ The statutory dose limits for radiation workers are 100 mSv per five years and 50 mSv per year. Five-year period started
from April, 2016, so that FY 2016-2019 data are given above.
・ How to read the numbers in table above：The number "173" in the box for the dose row of "5< Dose ≤10" and in column of the№ of work sites in five years of "4"column means that there were 173 workers who engaged in radiation works at four worksites in four years and whose radiation doses were greater than 5 and less than or equql to 10 millisieverts from FY 2016
to 2020.