Occupation Radiation Exposure in Taiwan, Republic of China, 2016
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 2016, collects and analyzes occupational external radiation exposure data read from Thermolucent Dosimeters worn by radiation workers from 2000 to 2016 (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 52,369 radiation workers in Taiwan in 2016, with yearly increase from 28,856 radiation workers in 2000. The average increase rate in recent 17 years is 3.86 %. There were 367 persons increase from 2015 to 2016, i.e., an increase rate of 0.71%, mainly from medical radiation workers. The increase rates is 4.42% 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 Dosage values
Collective dose in 2016 is 7.34 man-sieverts. Domestic average annual collective dose is approximately 9.67 man-sieverts. Major dose are from nuclear fuel cycle, industrial and medical categories. Their annual collective dose occupied 76.05%, 6.89% and 14.67% respectively, as shown in Figure 2. In 2016, the average dose of workers with measurable dose is 1.23 mSv, and the average dose over total radiation workers is 0.14 mSv. Average annual dose of workers with measurable dose is 1.69 mSv from 2000 to 2016. Average annual dose for total monitored persons is 0.25 mSv from 2000 to 2016, which has a downward trend, as shown in Figure 3.
Figure 3 Average Annual Dosage value
Figure 4 Number of Persons with Annual Dosage value 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 0 in 2016, as shown in Figure 4.