Radiation Dose Statistics for Nuclear Workers in FY 2018
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) 2018that 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, Naka*, Kansai*, Takasaki*, 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)*Note: The operation of Naka, Kansai, and Takasaki was transferred from JAEA to QST on April
1, 2016.
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 June
1, 2019(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, 2019.
(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.
2(4) Transient dose: Dose statistics within statutory five-year period(5) 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 data
were compiled. The total number of work sites in FY 2019 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.
(6) Number of work sites in three years：Number of work sites in three years means the number ofnuclear sites where workers were engaged in radiation works during the period of statistical datacompilation (FY 2016 and 2018).
List of dose statistics
1. Dose Distribution of Workers by Age ｛FY 2018｝(Table)
2. Dose Distribution of Workers by Age ｛FY 2018｝(Figure)
3. Dose Distribution of Workers by Age ｛FY 2018｝(Excluding the Data for Fukushima Daiichi Nuclear
Power Plant) (Figure)
4. Dose Distribution of Workers by Age ｛FY 2018｝(Excluding the data for Fukushima Daiichi Nuclear
Power Plant) (Table)
5. Annual Trends of Numbers of Workers by Age｛FY 2014-2018｝ (Figure)
6. Annual Trends of Numbers of Workers by Dose Range｛FY 2014-2018｝ (Figure)
7. Dose Distribution of Workers by Gender ｛FY 2018｝ (Table)
8. Dose Distribution of Workers by Number of Work Sites ｛FY 2018｝ (Table)
9. Ratio of Number of Workers by Number of Work Sites ｛FY 2018｝ (Figure)
10. Annual Trends of Ratio of Workers by Number of Work Sites {FY 2014-2018｝ (Figure)
11. Dose Distribution of Workers by Number of Work Sites ｛FY 2018｝(Excluding the Data for
Fukushima Daiichi Nuclear Power Plant）(Table)
12. Dose Distribution of Workers by Number of Work Sites ｛FY 2018｝（Excluding the Data for
Fukushima Daiichi Nuclear Power Plant)(Figure)
13. Transient Dose Distribution of Workers by Number of Work Sites in Latest three Years ｛FY 20162018｝(Table)

31．Dose Distribution of Workers by Age {FY 2018}
Number of workers

Dose(mSv)
AgeDose≤１1＜Ｄｏｓｅ 2.5＜Ｄｏｓｅ 5＜Ｄｏｓｅ 7.5＜Ｄｏｓｅ 10＜Ｄｏｓｅ 15＜Ｄｏｓｅ 20＜Ｄｏｓｅ 25＜Ｄｏｓｅ 30＜Ｄｏｓｅ 40＜Ｄｏｓｅ 50＜≤2.5
≤5
≤7.5
≤10
≤15
≤20
≤25
≤30
≤40
≤50
ＤｏｓｅTotal no. ofwokers(％)

DoseCollectiveMeandoseMax（person・mSv） （mSv） （mSv）

18～19458

96000000000473(0.7)

52.8

20～243,407

13584

26

14133000003,682(5.8)

1,224.0

0.3 17.1

25～29

6,332

331

148

67

4540

130

00

0

0

6,976 (10.9)

2,971.7

0.4 19.2

30～34

5,877

319

188

84

51

76

28

0

0

0

0

0

6,623 (10.3)

4,017.5

0.6 19.1

35～39

5,900

394

210

80

57

85

37

0

0

0

0

0

6,763 (10.6)

4,471.1

0.7 19.4

40～44

7,592

459

225

87

62

105

42

0

0

0

0

0

8,572 (13.4)

5,188.9

0.6 19.7

45～49

7,955

450

258

104

68

101

36

0

0

0

0

0

8,972 (14.0)

5,305.4

0.6 19.3

50～54

6,934

430

2088662

73

51

0

00

0

0

7,844 (12.3)

4,782.7

0.6 19.9

55～59

6,425

371

180

7152

60

31000

0

0

7,190 (11.2)

3,789.3

0.5 18.6

60～64

4,279

249

128

46

29

46

24

0

00

0

0

4,801(7.5)

2,656.0

0.6 19.2

65～69

1,605

106

35

15

129

10

0

0

0

0

0

1,792(2.8)

881.7

0.5 18.870 or more

291

115

1

03

2

000

00

313(0.5)

127.5

0.4 19.4

Total no. ofwokers

57,055

3,264

1,675

667

452

611

277

00000

64,001 (100.0)

－－

(％）

(89.2)

(5.1)

(2.6)

(1.0)

(0.7)

(1.0)

(0.4)

(0.0)

(0.0)

3,982.0 5,302.8 5,911.7 4,121.3 3,947.7 7,476.4 4,726.6

0.0

0.0

－

35,468.6

Collective
Dose(person・mSv）

0.1

3.4

－

(0.0) (0.0) (0.0)
0.0

0.0

0.0

0.6 19.9［Notes］
・ How to read the numbers in table above:The number "331" in the box for the age row of "25～29" and the dose column of "1<Dose≤2.5" means that there

were 331 workers between age 25 and 29 inclusive whose radiation doses were in the range of greater than 1 and less than or equal to 2.5
millisieverts in FY 2018.
・ The workers' ages are calculated as of March 31, 2019.

2．Dose Distribution of Workers by Age {FY 2018}
11,000
10mSv＜Dose

Number of workers

10,0005＜Dose≤10mSv

9,000

1＜Dose≤5mSv

8,000

Dose≤1mSv

7,000
6,000
5,000
4,000
3,000
2,000
1,000
0Age
＊ This figure is based on the data in the Table １ "Dose Distributin of Workersby Age {FY 2018}".

3．Annual Trends of Number of Workers by Age{FY 2014－2018}
12,000fiscal year
2014
2015
2016
2017
2018

Number of workers

10,000

8,000

6,000

4,000

2,000

0Age
＊ This figure is based on the data in the Table １ "Dose Distributin of Workers

by Age {FY 2018}" and those of the latest four years {FY 2014－2017}.
＊ Dose data of the emergency workers at Fukushima-Daiichi Nuclear Power Plant

are not included.

4.Annual Trends of Number of Workers by Dose Range{FY 2014-2018}
12,00065,00060,00011,000fiscal year

55,00010,000

2014
2015
2016
2017
2018

Number of workers

50,000
9,000

8,000
7,000
6,000
5,000
4,000
3,000
2,0001,0000Dose（mSv)＊ This figure is based on the data in the Table 1 "Dose Distributin of Workers by Age{FY 2018}"and those of the latest four years {FY 2014－2017}.
＊ Dose data of the emergency workers at Fukushima-Daiichi Nuclear Power Plant are notincluded.

5．Dose Distribution of Workers by Age{FY 2018}(Excluding the Data for Fukushim-Daiichi Nuclear Power Plant)
Number of workers

Dose(mSv)
AgeDose≤11<Dose

2.5<Dose5<Dose≤2.5

≤5

≤7.5

Total no. of wokers

7.5<Dose 10<Dose 15<Dose 20<Dose 25<Dose 30<Dose 40<Dose 50<Dose≤10≤15

≤20

≤25

≤30

≤40

≤50(％)

Dose
CollectiveDose

MeanMax（person・mSv） （mSv）

（mSv）

18～19

461

5

1

000000000467(0.9)

29.9

0.1

3.1

20～24

3,273

84

45

4

5

0

00

000

0

3,411(6.3)

531.2

0.2

9.3

25～29

6,004

181

54

122

2

000

0

0

0

6,255(11.6)

900.0

0.1

13.0

30～34

5,467

142

73

17

6

3

00000

0

5,708

(10.6)

990.2

0.2

12.4

35～39

5,422

194

68

15

62

0000005,707(10.6)

1,025.0

0.2

13.3

40～44

6,930

186

66

18

6

1

0000

0

0

7,207(13.4)

1,077.7

0.1

12.6

45～49

7,132

143

70

18

5

1

00

0

0

0

0

7,369(13.7)

1,000.7

0.1

11.2

50～54

6,118

153

40

10

4

1

0

0

0

0

0

0

6,326(11.7)

777.2

0.1

11.3

55～59

5,679

103

41

18

102

0

0

0

0

0

0

5,853

(10.9)

745.7

0.1

13.1

60～64

3,748

90

40

104

1

0

0

0

0

0

0

3,893(7.2)

548.6

0.1

11.1

65～69

1,406

43

113

1

0000000

1,464(2.7)

205.5

0.1

8.0

70 or more

26011100000000263(0.5)

21.5

0.1

6.8

Total no. ofwokers

51,9001,325510

12649

13000000 53,923(100.0)－－－(％）(96.3)(2.5)

7,853.2

0.1

13.3

Collective Dose(person・mSv）(0.9) (0.2) (0.1) (0.0) (0.0) (0.0) (0.0) (0.0) (0.0) (0.0)

2,621.9 2,130.2 1,765.0 764.9 419.2 152.1

0.0

0.0

0.0

0.0

0.00.0－［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 "181" in the box for the age row of "25～29" and the dose column of "1<Dose≤2.5" means that there were
181 workers between age 25 and 29 inclusive whose radiation doses were in the range of greater than 1 and less than or equal to 2.5 millisieverts in FY
2018.
・The workers' ages are calculated as of March 31,2019.

6．Dose Distribution of Workers by Age{FY 2018}(Excluding the Data for Fukushima-Daiichi Nuclear Power Plant)
9,000
10mSv＜Dose8,000

5＜Dose≤10mSv
1＜Dose≤5mSv

Number of workers

7,000Dose≤1mSv

6,000
5,000
4,000
3,000
2,000
1,000
0Age

＊ This figure is based on the data in the Table 5 "Dose Distribution of Workers by Age{FY2018}(Excluding the data for Fukushima-Daiichi Nuclear Power Plant)".

7．Dose Distribution of Workers by Gender{FY 2018}
GenderDose(mSv)

MaleFemale

Total no. ofwokers

Collective dose(person･mSv)

（％）

（％）

（％）

(％）

Total no. of wokers

56,198(89.0)
3,261(5.2)
1,675(2.7)
667(1.1)452(0.7)
611(1.0)277(0.4)0(0.0)
0(0.0)
0(0.0)
0(0.0)
0(0.0)
63,141857(99.7)3(0.3)
0(0.0)
0(0.0)
0(0.0)
0(0.0)
0(0.0)
0(0.0)
0(0.0)
0(0.0)
0(0.0)
0(0.0)
860

57,055(89.1)
3,264(5.1)
1,675(2.6)
667
(1.0)
452(0.7)
611(1.0)277(0.4)0(0.0)
0(0.0)
0(0.0)
0(0.0)
0(0.0)
64,001

3,982.0(11.2)
5,302.8(15.0)
5,911.7(16.7)
4,121.3(11.6)
3,947.7(11.1)
7,476.4(21.1)
4,726.6(13.3)
0.0
(0.0)
0.0
(0.0)
0.0
(0.0)
0.0
(0.0)
0.0
(0.0)
35,468.5（％）(100.0)(100.0)(100.0)(100.0)Total no. of wokers

63,141860

Ratio of man and famel(％）(98.7)

(1.3)

0.6

0.0

0.6

45,259.8

13.2

45,273.0

19.9

2.5

19.9

Dose ≤11< dose ≤2.5
2.5< Dose ≤55< Dose ≤7.5
7.5< Dose ≤10
10< Dose ≤15
15< Dose ≤20
20< dose ≤25
25< Dose ≤30
30< Dose ≤40
40< Dose ≤50
50< DoseMean dose（mSv）
Collective dose(person・mSv）
Max dose(mSv）［Notes］
・ How to read the numbers in table above：The number "3,261 " in the box of thedose row "1 < Dose ≤2.5 mSv" and the "Male" column means that there were
3,261 man workers whose radiation doses were in the range of greater than 1and less than or equal to 2.5 millisieverts in FY 2018.

8．Dose Distribution of Workers by Number of Work Sites{FY 2018}
No. of Worksites

123456or more

Dose（mSv)

Dose ≤ 5

Total no. ofwokers(%)

54,905

5,873

903

232

51

30

61,994(96.9)

5< Dose ≤10

947

146

22

3

10

1,119(1.7)

10< Dose ≤15

539

60

9

300611(1.0)

15< dose ≤20256210000277(0.4)

20 <Dose ≤250000000(0.0)

25< Dose ≤300000000(0.0)

30< Dose ≤400000000(0.0)

40< Dose ≤500000000(0.0)

50< Dose

0000000(0.0)

Total no. of wokers

56,647

6,100934

238

52

30

64,001（％）(88.5)

(9.5)

(1.5)

(0.4)

(0.1)

(0.0)

(100.0)

0.5

0.7

0.8

0.8

0.5

0.3

0.6

Mean dose（mSv）［Notes］
・ How to read the numbers in table above：The number "51" in the box forthe dose row of "Dose≤5" and the number of work sites of "5" column meansthat there were 51 workers who were engaged in five work sites and whoes
radiation doses were less than 5 millisievert in FY 2018.

9．Ratio of Number of Workers by Number ofWork Sites{FY 2018}
100%20mSv＜Dose15＜Dose≤20mSv
10＜Dose≤15mSv
5＜Dose≤10mSv
Dose≤5mSv

Ratio of number of workers

90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
１２３４５

６or more

Numbers of engaged nuclear sites＊ This figure is based on the data in the Table 8 "Dose Distribution ofWorkers by Number of Work Sites {FY 2018}".

10．Annual Trends of Ratio of Workers by
Number of Work Sites {FY 2013-2017}100%

Ratio of number of workers

90%４sites more３sites２sites
１site

80%
70%
60%
50%
40%30%20%
10%0%
2014

20152016

2017

2017

Fiscal year

＊ This figure is based on the data in the Table 8 "DoseDistribution of Workers by Number of Work Sites {FY 2018}" andthose of the latest four years {FY 2014－2017}.
＊ Dose data of the emergency workers at Fukushima-Daiichi
Nuclear Power Plant are not included.

11．Dose Distribution of Workers by Number of Work Sites{FY 2018}(Excluding the Data for Fukushima-Daiichi Nuclear Power Plant)
No. of Worksites
Dose（mSv)

1234

56or moreTotal no. ofwokers(%)≤ 547,502

5,130814

21250

27 53,735(99.7)

5< Dose ≤101006210210175(0.3)

10 < Dose ≤1534600013(0.0)

15< Dose ≤200000000(0.0)

20< Dose ≤250000000(0.0)

25< Dose ≤300000000(0.0)

30< Dose ≤400000000(0.0)

40< Dose ≤500000000(0.0)

50 < Dose

0000000(0.0)

Total no. of wokers

47,605

5,196830

21451

2753,923（％）(88.3)(9.6) (1.5) (0.4) (0.1)(0.1)(100.0)

0.4

0.1

0.1

Dose

Means dose（mSv）

0.1

0.6

0.6

0.4

［Notes］
・ 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 "50" in the box for thedose row of "Dose≤5" and the number of work sites of "5" column means that
there were 50 workers who were engaged in five nuclear sites and whoes
radiation doses were less than 5 millisievert in FY 2018.

12．Dose Distribution of Workers by Number of Work Sites{FY 2018}(Excluding the Data for Fukushima-Daiichi Nuclear Power Plant)
100%
90%
Ratio of number of workers

80%

20mSv＜Dose15＜Dose≤20mSv
10＜Dose≤15mSv
5＜Dose≤10mSv
Dose≤5mSv

70%
60%
50%
40%
30%
20%
10%
0%
123456or more

Numbers of engaged nuclear facilities＊ Thisfigure is based on the data in the Table 11 "DoseDistribution of Workers by Number of Work Sites {FY 2018}".

13．Transient Dose Distribution of Workers by Number of Work Sites
in Latest three Years {FY 2016-2018}
No. of work sites
in three years

1234567

Dose（mSv）
Dose≤ 567,983

5< Dose ≤ 10

2,278

542

10< Dose ≤ 15

1,096

15< Dose ≤ 20

11,392 2,865

Total no. ofworkers

8or more(%)

938

338

148

46

38

83,748 (92.1)

199

81

44

15

72

3,168(3.5)

225

67

31

126

20

1,439(1.6)

763

162

41

185

110991(1.1)

20< Dose ≤ 2539584

2680300516(0.6)

25< Dose ≤ 30

255

56

1021001325(0.3)

30< Dose ≤ 40

34161

1610000419(0.5)

40< Dose ≤ 50

147

28400000179(0.2)

50< Dose ≤ 60

59

300000062(0.1)

60< Dose ≤ 70

13100000014(0.0)

70< Dose ≤ 80

11000000011(0.0)

80< Dose ≤ 90

000000000(0.0)

90< Dose ≤ 100

000000000(0.0)

100< Dose000000000(0.0)

400173Total no. of workers

73,341

12,554 3,228 1,079

56

41

90,872（％）(80.7)(13.8) (3.6) (1.2) (0.4) (0.2) (0.1)(0.0)(100.0)Mean dose（mSv)

1.4

1.3

1.5

1.8

2.0

2.2

2.2

2.3

2.3

［Notes］
・ The statutory dose limits for radiation workers are 100 mSv per five years and 50 mSv peryear. Five-year period started from April, 2016, so that FY 2016-2018 data are given
above.
・ How to read the numbers in table above：The number "81" in the box for the dose row of"5< Dose ≤10" and in column of the no. of work sites in three years "4" means that there
were 81 workers who engaged in radiation works at four work sites in three years andwhose radiation doses were greater than 5 and less than or equql to 10 illisieverts fromFY 2016 to 2018.