In the dismantling process of a reactor coolant system (RCS) piping, a radiation protection plan should be established to minimize the radiation exposure doses of dismantling workers. Hence, it is necessary to estimate the individual effective dose in the RCS piping dismantling process when decommissioning a nuclear power plant. In this study, the radiation exposure doses of the dismantling workers at different positions was estimated using the MicroShield dose assessment program based on the NUREG/CR-1595 report. The individual effective dose, which is the sum of the effective dose to each tissue considering the working time, was used to estimate the radiation exposure dose. The estimations of the simulation results for all RCS piping dismantling tasks satisfied the dose limits prescribed by the ICRP-60 report. In dismantling the RCS piping of the Kori-1 or Wolsong-1 units in South Korea, the estimation and reduction method for the radiation exposure dose, and the simulated results of this study can be used to implement the radiation safety for optimal dismantling by providing information on the radiation exposure doses of the dismantling workers.

1. Introduction
2. Materials and methods
    2.1 Detailed dismantling process of RCS piping
    2.2 Simulation input parameters of the MicroShieldprogram
3. Results
    3.1 Estimation of radiation exposure dose indismantling tasks
    3.2 Comparisons of reduction methods forradiation exposure dose
4. Conclusions
REFERENCES

• Taewoong Lee(Global Institute of Technology, KEPCO KPS) Corresponding Author
• Seongmin Jo(Global Institute of Technology, KEPCO KPS)
• Sunkyu Park(Global Institute of Technology, KEPCO KPS)
• Nakjeom Kim(Global Institute of Technology, KEPCO KPS)
• Kichul Kim(Nuclear Maintenance Engineering Center, KEPCO KPS)
• Seongjun Park(Nuclear Maintenance Engineering Center, KEPCO KPS)
• Changyeon Yoon(Central Research Institute, Korea Hydro & Nuclear Power)