## 3 Results
The main input data to the NORMALYSA code for the exposure dose evaluation was AC, which was categorized into two groups, below and above 1 Bq/g, as used in RESRAD codes. The results for both categories of AC are summarized in Figure 8. The total dose obtained using NORMALYSA code with AC below 1000 Bq/kg over the modeling period of 40 years was 1.29 mSv/y, which is above the ICRP-recommended public dose limit of 1 mSv/y. However, the total dose from AC above 1000 Bq/kg was 32 mSv/y, which is significantly above 1 mSv/y. This high dose was due to the high AC that is mainly contributed by \({}^{232}\)Th. In comparison, the results from RESRAD-ONSITE and NORMALYSA codes were significantly high, and people should not settle on NORM-contaminated landfill sites without regulatory control. Figure 9 compares the results for RESRAD-ONSITE, RESRAD-OFFSETITE, HotSpot, and NORMALYSA codes. For RESRAD-ONSITE, doses for ACs above 1 Bq/g were high, with a maximum value of 2.30E + 01 mSv/y, because of high ACs that are mainly contributed by the inhalation of radon and thoron decay products, whereas doses for ACs below 1 Bq/g were all below the ICRP-recommended public dose limit of 1 mSv/y, with a maximum value of 8.80E-01 mSv/y, because of a significant low AC considered in the simulation. The total dose obtained from RESRAD-OFFSETITE for AC ranges below and above 1 Bq/g for an offsite resident was below the ICRP-recommended public dose limit of 1 mSv/y. Therefore, it is safe for people to reside within a vicinity of a landfill site as offsite residents. The highest dose obtained using the HotSpot code for stability class A with ACs below and above 1000 Bq/kg at a distance of 0.03 km from the release point was 0.47 mSv/y, which is below the ICRP-recommended dose limit of 1 mSv/y, and 4.3 mSv/y, which is above the ICRP-recommended public dose limit of 1 mSv/y. Higher doses were due to high ACs above 1000 Bq/kg. The total dose from NORMALYSA code with AC below 1000 Bq/kg was 1.29 mSv/y, which is above the ICRP-recommended public dose limit of 1 mSv/y, whereas the total dose from AC above 1000 Bq/kg was 32 mSv/y, which is significantly above 1 mSv/y. The high dose is attributed to the high AC, which is mainly caused by the decay of \({}^{238}\)U and \({}^{232}\)Th. Therefore, people should not settle on NORM-contaminated landfill sites without clearance from the competent authority. \begin{table}
\begin{tabular}{c c c} \hline
**Input Parameter** & **Value** & **Reference** \\ \hline Activity concentration & Same as RESRAD & NSSC \\ Concentration of radionuclides in outdoors air & & \\ \({}^{238}\)U & 6.0 \(\times\) 10\({}^{-8}\) Bq/m\({}^{3}\) & \\ \({}^{232}\)Th & 2.0 \(\times\) 10\({}^{-7}\) Bq/m\({}^{3}\) & [28] \\ \({}^{40}\)K & 2.9 \(\times\) 10\({}^{-10}\) Bq/m\({}^{3}\) & \\ Fraction of the year a person stays within the & & \\ contaminated site & 0.25 & RESRAD default \\ Soil bulk density & 1.5 g/cm\({}^{3}\) & RESRAD default \\ Ambient external dose rate outdoors & 1.2 \(\times\) 10\({}^{-7}\) Sv/h & NORMALYSA default \\ Conversion factor from ambient to effective dose & 0.6 & NORMALYSA default \\ Dose coefficient for effective dose by inhalation & & \\ \({}^{238}\)U & 8.0 \(\times\) 10\({}^{-8}\) & \\ \({}^{232}\)Th & 1.1 \(\times\) 10\({}^{-4}\) & \\ \({}^{40}\)K & 2.9 \(\times\) 10\({}^{-9}\) & NORMALYSA default \\ Time of calculation & 1000 years & Same as RESRAD \\ Area of contaminated site & 659 m\({}^{2}\) & Korea Statistics 2018 \\ \hline \end{tabular}
\end{table} 
Table 6: Summary of NORM and LegacY Site Assessment input parameters.