Occupation Radiation Exposure in Taiwan, Republic of China, 2018
According to Paragraph 1 of Article 15 of Ionizing Radiation Protection Act (IRPA) : To ensure that radiation workers’ occupational exposure is below limits and kept as low as reasonably achievable, the employer shall monitor each radiation worker's dose. In order to monitor domestic radiation workers and their dose data to reach the safety goal of radiation protection, Atomic Energy Council (AEC) according to the authorization of Paragraph 5 of Article 15 of IRPA, establish National Database Center of Occupational Radiation Exposures (NDCORE) to collect and conduct statistical analysis of domestic radiation workers and their doses.
The annual report of NDCORE contains each working category in 2018, collects and analyzes occupational external radiation exposure data read from Thermolucent Dosimeters worn by radiation workers from 2000 to 2018 (with dosage value from neutron badges already included). Statistical results include: number of monitored persons and average dose in each dose interval, collective dose in each dose interval, number of persons in each age interval and sex group, and average monthly dose.
There were 52,995radiation workers in Taiwan in 2018, with yearly increase from 28,856 radiation workers in 2000. The average increase rate in recent 19years is 3.50 %. There were 746 persons increase from 2017 to 2018, i.e., an increase rate of 1.43%, mainly from Medical and industrial radiation workers. The increase rate is 3.65% and 2.75% respectively, as shown in Figure 1. Yearly ratio of male workers to female workers remains approximately at 7:3.
Figure 1 Population of Radiation Workers
Figure 2 Total Collective Dose Values
Collective dose in 2018 is 5.78 man-sieverts. Domestic average annual collective dose is approximately 9.26 man-sieverts. Major dose are from nuclear fuel cycle, medical and industrial categories. Their annual collective dose occupied 70.68%, 21.03% and 6.54% respectively, as shown in Figure 2. In 2018, the average dose of workers with measurable dose is 1.13 mSv, and the average dose over total radiation workers is 0.11 mSv. Average annual dose of workers with measurable dose is 1.63 mSv from 2000 to 2018. Average annual dose for total monitored persons is 0.24 mSv from 2000 to 2018, which has a downward trend, as shown in Figure 3.
Figure 3 Average Annual Dose Values
Figure 4 Number of Persons with Annual Dose Values Greater than 50 and 20 mSv
The number of radiation workers with annual dose over than 50 mSv is distributed between 0 and 2. The number of workers with annual dose exceeding 20 mSv is observed from 101 in 2000 reducing to 2 in 2018, as shown in Figure 4.