Radiation Dose Statistics for Nuclear Workers in FY 2017
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) 2017that 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 fiscal year 2016, the dose statistics of emergency workers for 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 onApril 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, 2017.
(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, 2017.
(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 to2

control long-term dose limit. The first period started on April 1, 2001, with exposure doses
accumulating every subsequent five years.
(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 2017 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 two years：Number of work sites in two years means the number ofnuclear sites where workers were engaged in radiation works during the period of statistical datacompilation (FY 2016 and 2017).
List of dose statistics
1. Dose Distribution of Workers by Age ｛FY 2017｝(Table)
2. Dose Distribution of Workers by Age ｛FY 2017｝(Figure)
3. Dose Distribution of Workers by Age ｛FY 2017｝(Excluding the Data for Fukushima Daiichi Nuclear
Power Plant) (Figure)
4. Dose Distribution of Workers by Age ｛FY 2017｝(Excluding the data for Fukushima Daiichi Nuclear
Power Plant) (Table)
5. Dose Distribution of Workers by Gender ｛FY 2017｝ (Table)
6. Annual Trends of Numbers of Workers by Age｛FY 2013-2017｝ (Figure)
7. Annual Trends of Numbers of Workers by Dose Range｛FY 2013-2017｝ (Figure)
8. Dose Distribution of Workers by Number of Work Sites ｛FY 2017｝ (Table)
9. Ratio of Number of Workers by Number of Work Sites ｛FY 2017｝ (Figure)
10. Annual Trends of Ratio of Workers by Number of Work Sites {FY 2013-2017｝ (Figure)
11. Dose Distribution of Workers by Number of Work Sites ｛FY 2017｝(Excluding the Data for
Fukushima Daiichi Nuclear Power Plant）(Table)
12. Dose Distribution of Workers by Number of Work Sites ｛FY 2017｝（Excluding the Data for
Fukushima Daiichi Nuclear Power Plant)(Figure)
13. Transient Dose Distribution of Workers by Number of Work Sites in Latest two Years ｛FY 20162017｝(Table)

31．Dose Distribution of Workers by Age {FY 2017}
Number of workers

Dose(mSv)
Age

Dose≤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(％)

DoseCollective
Mean
doseMax（person・mSv） （mSv） （mSv）

18～19433

138220000000458(0.7)

97.9

20～243,536

173

8230

161721100

003,876(5.8)

1,694.4

0.4 24.4

25～29

6,589

332

178

83

28

65

37

2

3

1

0

0

7,318 (10.9)

4,012.2

0.5 30.9

30～34

6,104

354

208

89

64

79

44

4

0

1

0

0

6,947 (10.4)

4,736.7

0.7 32.7

35～39

6,233

420

197

97

56

83

79

9

0

0

0

0

7,174 (10.7)

5,531.3

0.8 24.4

40～44

8,231

504

272

109

77

89

68

8

6

3

0

0

9,367 (14.0)

6,428.7

0.7 31.6

45～49

8,019

543

323

117

73

114

81

9

9

0

0

0

9,288 (13.8)

7,218.4

0.8 28.450～54

7,132

472

232

111

76

92

80

3

5

1

00

8,204 (12.2)

6,270.3

0.8 30.1

55～59

6,592

425

204

83

67

86

51

3

3

1

00

7,515 (11.2)

5,019.5

0.7 30.1

60～64

4,270

278

150

53

34

54

31

3

0

0

0

0

4,873

(7.3)

3,174.6

0.7 24.9

65～69

1,542

84

43

18

9

20

8

0

0

0

0

0

1,724(2.6)

979.1

0.6 17.970 or more

239

8

6

4

1

1

1

0

0

0

0

0

260(0.4)

109.8

0.4 17.9

Total no. ofwokers

58,920

3,606

1,903

796

503

700

501

4226700

67,004 (100.0)

－－

(％）

(87.9)

(5.4)

(2.8)

(1.2)

(0.8)

(1.0)

(0.7)

(0.1)

(0.0)

(0.0) (0.0) (0.0)

4,215.0 5,918.0 6,710.1 4,911.1 4,392.7 8,745.9 8,511.2

944.5

708.3

216.2

－

45,273.0

Collective
Dose(person・mSv）

0.0

0.0

0.2

9.5

－

0.7 32.7［Notes］
・ How to read the numbers in table above:The number "332" in the box for the age row of "25～29" and the dose column of "1<Dose≤2.5" means that there

were 332 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 2017.
・ The workers' ages are calculated as of March 31, 2018.

42．Dose Distribution of Workers by Age {FY 2017}
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 2017}.

53．Dose Distribution of Workers by Age{FY 2017}(Excluding the Data for Fukushim-Daiichi Nuclear Power Plant)
Number of workers

Dose(mSv)
Age

Dose≤11<Dose2.5<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）

18～1943464110000000446(0.8)

59.1

0.1

9.5

20～243,40586

348

420000003,539(6.5)

526.80.111.8

25～296,217137

55

198

7

1

00

0

0

0

6,444(11.8)

1,053.9

0.2

15.2

30～34

5,651136

45

172

6

0

0

0

0

0

0

5,857(10.8)

851.5

0.1

14.6

35～39

5,694

155

52

12

7

4

2

0

0

0

0

0

5,926

(10.9)

967.1

0.2

16.5

40～44

7,378

188

63

15

7

7

0

0

0

0

0

0

7,658(14.1)

1,142.3

0.1

14.6

45～49

6,993

173

51

135

6

0

1

00

0

0

7,242(13.3)

985.5

0.1

21.0

50～54

6,115

130

35

169

5

00

0

0

00

6,310

(11.6)

852.5

0.1

14.8

55～59

5,642

99

4494

30000

0

0

5,801(10.7)

658.2

0.1

12.9

60～643,599

70

304

6

30000

00

3,712(6.8)

477.8

0.1

13.8

65～69

1,268

288

3

2

00

0

0

0

00

1,309(2.4)

164.7

0.1

9.9

70 or more

209

101

100

0

0

00

0

212(0.4)

22.0

0.1

7.8

Total no. of
wokers52,605

1,209

421

118

56

43

3

100

0

0 54,456(100.0)－－－(％）(96.6)(2.2)

7,761.3

0.1

21.0Collective Dose(person・mSv）(0.8) (0.2) (0.1) (0.1) (0.0) (0.0) (0.0) (0.0) (0.0) (0.0)

2,595.1 1,910.7 1,427.2 724.5 486.4 548.9

47.5

21.0

0.0

0.0

0.0

0.0

－

［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 "137" in the box for the age row of "25～29" and the dose column of "1<Dose≤2.5" means that there were137 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 inFiscal 2017.
・The workers' ages are calculated as of March 31,2018.
6

4．Dose Distribution of Workers by Age{FY 2017}(Excluding the Data for Fukushima-Daiichi Nuclear Power Plant)
9,000
10mSv＜Dose
8,000

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 3 "Dose Distribution of Workers by Age{FY2017}(Excluding the data for Fukushima-Daiichi Nuclear Power Plant)."
7

5．Dose Distribution of Workers by Gender{FY 2017}
GenderDose(mSv)

FemaleMale

Total no. ofwokers

Collective dose
(person･mSv)

（％）

（％）

（％）

(％）

Total no. of wokers

58,105(87.8)
3,603
(5.4)
1,903
(2.9)
796
(1.2)
503
(0.8)
700(1.1)
501(0.8)42(0.1)26(0.0)7(0.0)
0(0.0)
0(0.0)
66,186815(99.6)3(0.4)
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)
818

58,920(87.9)
3,606(5.4)
1,903
(2.8)
796(1.2)503(0.8)700(1.0)501(0.7)42(0.1)26(0.0)7(0.0)
0(0.0)
0(0.0)
67,0044,215.0(9.3)
5,918.0(13.1)
6,710.1(14.8)
4,911.1(10.8)
4,392.7(9.7)
8,745.9(19.3)
8,511.2(18.8)
944.5
(2.1)
708.3
(1.6)
216.2
(0.5)
0.0(0.0)
0.0(0.0)
45,273.0（％）(100.0)(100.0)(100.0)(100.0)Total no. of wokers

66,186818

Ratio of man and famel(％）(98.8)

(1.2)

0.7

0.0

0.7

45,259.8

13.2

45,273.0

32.7

1.5

32.7

Dose ≤1
1< dose ≤2.5
2.5< Dose ≤55< Dose ≤7.5
7.5< Dose ≤1010< Dose ≤1515< Dose ≤20
20< dose ≤25
25< Dose ≤30
30< Dose ≤4040< Dose ≤50
50< Dose

Mean dose（mSv）
Collective dose
(person・mSv）
Max dose(mSv）［Notes］
・ How to read the numbers in table above：The number "3,603 " in the box of thedose row "1 < Dose ≤2.5 mSv" and the "Male" column means that there were
3,603 man workers whose radiation doses were in the range of greater than 1and less than or equal to 2.5 millisieverts in FY 2017.

8

6．Annual Trends of Number of Workers by Age{FY 2013－2017}
12,000fiscal year
2013
2014
2015
2016
2017

Number of workers

10,000

8,000

6,000

4,000

2,000

0Age
＊ This figure is based on the data in the Table 5 "Dose Distribution of Workersby Gender{FY 2017} and those of the latest four years {FY 2013－2016}.
＊ Dose data of the emergency workers at Fukushima-Daiichi Nuclear Power Plant

are not included.

97.Annual Trends of Number of Workers by Dose Range{FY 2013-2017}
12,00065,00060,00011,000fiscal year

55,00010,000

2013
2014
2015
2016
2017

Number of workers

50,000
9,000

8,000
7,000
6,000
5,000
4,000
3,000
2,000
1,000
0

Dose（mSv)＊ This figure is based on the data in the Table 5 "Dose Distribution of Workers byGender{FY 2017}and those of the latest four years {FY 2013－2016}.
＊ Dose data of the emergency workers at Fukushima-Daiichi Nuclear Power Plant are notincluded.

10

8．Dose Distribution of Workers by Number of Work Sites{FY 2017}
No. of Worksites

123456or more

Dose（mSv)

Total no. ofwokers(%)

Dose ≤ 5

57,284

5,927940

214

42

22

64,429 (96.2)

5< Dose ≤10

1,111

139

37

10

1

11,299(1.9)

10< Dose ≤1561676

6200700(1.0)

15< dose ≤20463

371000501(0.8)

20 <Dose ≤25

420000042(0.1)

25< Dose ≤30260000026(0.0)

30< Dose ≤40

7000007(0.0)

40< Dose ≤500000000(0.0)

50< Dose

0000000(0.0)

Total no. of wokers 59,549

6,179

984

226

43

23

67,004(88.9)

(9.2)

(1.5)

(0.3)

(0.1)

(0.0)

(100.0)

0.7

0.8

0.8

0.8

0.7

0.2

0.7

（％）
Mean dose（mSv）［Notes］
・ How to read the numbers in table above：The number "42" in the box forthe dose row of "Dose≤5" and the number of work sites of "5" column
means that there were 42 workers who were engaged in five work sites andwhoes radiation doses were less than 5 millisievert in FY 2017.

119．Ratio of Number of Workers by Number ofWork Sites{FY 2017}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%
１２３４５６or more

Numbers of engaged nuclear sites＊ This figure is based on the data in the Table 8"Dose Distribution of Workers by Number of Work
Sites{FY 2017}".

12

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%
2013

2014

20152016

2017

Fiscal year

＊ This figure is based on the data in the Table 8 "DoseDistribution of Workers by Number of Work Sites［FY2017］and those of the latest four years.
＊ Dose data of the emergency workers at Fukushima-Daiichi
Nuclear Power Plant are not included.

13

11．Dose Distribution of Workers by Number of Work Sites{FY 2017}(Excluding the Data for Fukushima-Daiichi Nuclear Power Plant)
No. of Worksites
Dose（mSv)

123456or more

Total no. ofwokers(%)≤ 548,058

5,074853

190

41

19 54,235 (99.6)

5< Dose ≤109350

20

1010174 (0.3)

10 < Dose ≤15

319210043 (0.1)

15< Dose ≤201110003 (0.0)

20< Dose ≤25

1000001 (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

48,1845,134876201421954,456（％）(88.5)(9.4) (1.6) (0.4) (0.1) (0.0)(100.0)DoseMeans dose（mSv）

0.1

0.3

0.6

0.8

0.7

0.0

0.1

［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 "41" in the box for thedose row of "Dose≤5" and the number of work sites of "5" column means that
there were 41 workers who were engaged in five nuclear sites and whoes
radiation doses were less than 5 millisievert in FY 2017.
1412．Dose Distribution of Workers by Number of Work Sites{FY 2017}(Excluding the Data for Fukushima-Daiichi Nuclear Power Plant)
100%
90%
20mSv＜Dose
15＜Dose≤20mSv
10＜Dose≤15mSv
5＜Dose≤10mSv
Dose≤5mSv

Ratio of number of workers

80%
70%
60%
50%
40%
30%
20%
10%
0%
12

34

56or 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 2017}".

15

13．Transient Dose Distribution of Workers by Number of Work Sites
in Latest two Years {FY 2016-2017}

No. of work sites
in two years

12345

67

Dose（mSv）
Dose

≤ 5

64,057

5< Dose ≤ 10

1,966

383

10< Dose ≤ 15964

15< Dose ≤ 20

9,217 2,159

Total no. ofworkers

8or more(%)

609

196

86

19

1676,359 (93.3)

94

46

19

3

202,513(3.1)

184

45

10

12001,206(1.5)

643

92

24

11

100762(0.9)

20< Dose ≤ 2535050514000410(0.5)

25< Dose ≤ 30

21633320000254(0.3)

30< Dose ≤ 40

20211200000215(0.3)

40< Dose ≤ 50

61000000061(0.1)

50< Dose ≤ 60

15000000015(0.0)

60< Dose ≤ 70

800000008(0.0)

70< Dose ≤ 80

000000000(0.0)

80< Dose ≤ 90

000000000(0.0)

90< Dose ≤ 100

000000000(0.0)

100< Dose000000000(0.0)

669

22192

Total no. of workers

68,4829,970 2,332

2116

81,803（％）(83.7)(12.2) (2.9) (0.8) (0.3) (0.1) (0.0)(0.0)(100.0)Mean dose
（mSv)

1.2

0.2

1.2

1.3

1.4

1.4

1.9

1.2

0.8

［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 and 2017 data are given
above.
・ How to read the numbers in table above：The number "46" in the box for the dose row of"5< Dose ≤10" and in column of the no. of work sites in two years "4" means that there
were 46 workers who engaged in radiation works at four work sites in two years and whoseradiation doses were greater than 5 and less than or equql to 10 millisieverts from FY
2016 to 2017.

16