Radiation Dose Distribution for Workers in South Korean Nuclear Power Plants

A total of 33,680 nuclear power plants (NPPs) workers were monitored and recorded from 1990 to 2007. According to the record, the average individual radiation dose has been decreasing continually from it 3.20 mSv/man in 1990 to 1.12 mSv/man at the end of 2007. After the International Commission on Radiological Protection (ICRP) 60 recommendation was generalized in South Korea, no nuclear power plant workers received above 20 mSv radiation, and the numbers of relatively highly exposed workers have been decreasing continuously. The age distribution of radiation workers in nuclear power plants was composed of mainly 20-30- year-olds (83%) for 1990 ~ 1994 and 30-40-year-olds (75%) for 2003 ~ 2007. The difference in individual average dose by age was not significant. Most (77%) of NPP radiation exposures from 1990 to 2007 occurred mostly during the refueling period. With regard to exposure type, the majority of exposures were external exposures, representing 95% of the total exposures, while internal exposures represented only 5%. External effective dose was affected mainly by gamma radiation exposure, with an insignificant amount of neutron exposure. As for internal effective dose, tritium (3H) in the pressurized heavy water reactor (PHWR) was the biggest cause of exposure.

• B. I. Lee
• S. I. Kim
• D. H. Suh
• J. I. Kim
• Y. K. Lim

• Dose distribution
• External exposure
• Nuclear powerplant
• Occupational radiation dose

[1] World Nuclear Association, Information papers: Nuclear power in
Korea, WNA, 2009.
[2] Ministry of Education, Science and Technology, MEST notice 2008-31:
The standard about radiological protection, MEST,2008.
[3] International Commission on Radiological Protection, ICRP 103: 2007
Recommendations of the International Commission on Radiological
Protection, ICRP: 73, 2007.
[4] NCRP Report No. 122, ÔÇÿUse of Personal Monitors to Estimate Effective
Dose Equivalent and Effective Dose to Workers for External Exposure
to Low-LET Radiation- NCRP, 1995.
[5] Hee Geun Kim, Application and experience of a two-dosimeter
algorithm for better estimation of effective dose during maintenance
periods at Korea nuclear power plants, Applied Radiation and Isotopes,
Volume 67, 2009, pp. 1315-1319.
[6] Korea Hydro & Nuclear Power co., Yonggwang unit 3&4 procedure:
Management of radiation dose, KHNP.
[7] Ministry of Education, Science and Technology, MEST notice 2008-50:
The regulation about assessment and management of individual
radiation dose from external exposure, MEST, 2008.
[8] Ministry of Education, Science and Technology, MEST notice 2008-51:
The regulation about measurement and estimation of radiation dose from
internal exposure, MEST, 2008.
[9] United Nations Scientific Committee on the Effects of Atomic
Radiation, UNSCEAR report 2000: Sources and effects of ionizing
radiation, J. Radiol. Prot. 21(1), 2001, pp. 83-86.
[10] Yuan Tian, Dose level of occupational exposure in China, Radiation
protection dosimetry, 128(4), 2008, pp. 491-495.
[11] P. A. Colgan, An assessment of annual whole-body occupational
radiation exposure in Ireland(1996-2005), Radiation protection
dosimetry, 128(1), 2008, pp. 12-20.
[12] J. G. Alves, Occupational exposure in Portugal in 1999, Radiation
protection dosimetry, 96(1-3), 2001, pp. 43-47.
[13] Wu Weizhang, Occupational exposures of Chinese medical radiation
workers in 1986-2000, Radiation protection dosimetry, 117(4), 2005, pp.
440-443.
[14] Korea Hydro & Nuclear Power co., Root cause analysis of world best
performance achievement for dose reduction in Younggwang unit 3 & 4,
KHNP, 1998.
[15] World Association of Nuclear Operators, 2007 performance indicator,
WANO, 2008.
[16] Korea Hydro & Nuclear Power co., Annual report of nuclear power
plants' radiation management, KHNP, 2008.