In order to ensure the long-term safety of a deep geological repository, the performance assessment of the Engineered Barrier System (EBS) considering a thermal process should be performed. The maximum temperature at the side wall of a disposal canister for the technical design requirement should not exceed 100°C. In this study, the thermal modelling was conducted to analyze the effects of the thermal process from a disposal canister to the surrounding near-field host rock using the PFLOTRAN code. The mesh was generated using the LaGriT code and the material properties were assigned by applying the FracMan code. Initial conditions were set as the average geothermal gradient (25.7°C/km) and an average surface temperature (14.7°C) in Korea. The highest temperature was observed at the middle of the canister side wall. The temperature of the buffer was lower than that of the canister, and the temperature increase of the deposition tunnel and the host rock was insignificant due to the lower effect of the heat source. The result of the thermal evolution of the EBS represented the highest thermal effects in the vicinity of the canister. In addition, the thermal effects were largely decreased after 10 years of the entire simulation period. It demonstrated that the model took 3 years to heat up the buffer around the canister. The temperature at the canister side wall increased until 3 years and then decreased after that time. This is because that the radioactive decay heat from the heat source was emitted enough to raise the overall temperature of the EBS by 3 years. However, the decay heat rate of the canister decreased exponentially with the disposal time and then its decay heat was not emitted enough after 3 years. In conclusion, the peak temperature results of the EBS were lower than 70°C to meet the technical design requirement.

A radioactive waste disposal facility needs to be developed in a way to protect present and future generations and its environment. A safety assessment is implemented for normal and abnormal scenarios and human intrusion scenarios as a part of a safety case in developing a disposal facility for the radioactive waste. The human intrusion scenarios include a well scenario which takes into account various potential exposure groups (PEGs) who use a groundwater well contaminated with radionuclides released from the disposal facility. It is observed that a pumping rate has a negative correlation with the biosphere dose conversion factor (BDCF) in the well scenario. C-14 is shown to be a key radionuclide in the well scenario, and a special model based on the carbon cycle is applied for C-14. For Tc-99, an adsorption coefficient should be adjusted to be suitable for the site. The safety assessment for the radioactive waste disposal facility is successfully carried out for the well scenario. However, it is observed that site-specific models needs to be developed and sitespecific input data need to be collected in order to avoid unnecessary conservatism.

In order to dispose of spent nuclear fuel (SNF) in deep geological repository, source term evaluation considering its specification, enrichment, burnup, cooling time should be performed. In this study, the measured values of Takahama-3 pressurized water reactor SNF (WH 17×17) samples were analyzed with SCALE 6.1/ORIGEN-S and TRITON code calculation results for validation. Unlike the ORIGENS code, TRITON code calculations differed from two-dimensional neutron flux distribution by using the multi-group cross-section library. Both calculation results from ORIGEN-S and TRITON code showed higher errors in 234U, 239Pu, and 241Pu compared to other actinide nuclides. In the case of axial locations of fuel rods in fuel assembly, fuel rods located at the edge of the fuel assembly presented increased errors due to nuclear reaction cross-section. Overall, the ORIGEN-S predictions informed more accurate agreement with the measured results compared with TRITON results. Especially to 235U, 239Pu, and 240Pu radionuclides, ORIGEN-S errors were denoted more than twice as low as the TRITON results. Comparing the calculation results with experimental results implied that the ORIGENS code was more accurate code than the TRITON code for source term evaluation.

In biosphere assessment modeling for the safety assessment of the Wolsong LILW disposal facility, the multi-compartment modeling in which all radionuclides transport is described quantitatively in terms of transfer factors between various environmental compartments has been implemented. In order to reflect the actual transfer mechanisms of 14C in the environment the specific activity (SA) modeling approach can be applied as an alternative to the previous transfer factors (TF) approach. The assumption of full SA equilibrium throughout the terrestrial environment is completely satisfactory for 14C release to the atmosphere if the 12C is emitted as 14CO2. This is the only form that is readily taken up by plants, so that active carbon is incorporated into the plant via photosynthesis at the same rate as stable carbon. Accordingly, the 14C concentration in Bq/g stable carbon is the same in the plant as it is in the air. And animals take up carbon almost entirely through ingestion and the SA ratio in the plant is maintained in the animal. In this study, a specific activity model for 14C was implemented in a GoldSim biosphere assessment model. From the literature survey for existing specific activity models developed, the IAEA model was selected. The farming scenario utilizing well water was simulated and the resulting ingestion dose conversion factors (DCFs) from the IAEA SA model were compared with those of the TF approach. The parameter value for the concentration of stable carbon in the air (gC/m3) is used as 0.20 gC/m3 considering the Suess effect. The dose coefficient for food ingestion used for dose calculations was taken from ICRP-72 as 5.8E-10 Sv/Bq. It was found that the ingestion DCFs of the SA model showed about 3 times lower than those of the TF model in the farming scenario through irrigation of well water, so it is expected that the SA approach could be applied for a more realistic assessment. Though the comparisons were made on the results from the terrestrial ecosystem only in this study, it would be necessary to investigate the applicability of the SA modeling approach for 14C through extensive comparisons and analysis including an aquatic ecosystem, and through parameters survey suitable to the domestic condition.

목 적：New fast acquisition technique인 wave-CAIPIRINHA를 적용한 MPRAGE sequence를 통해 brain 의 국소병변 진단능과 화질의 변화를 알아보고자 한다. 대상 및 방법：2017년 11월 22일부터 2018년 1월 2일까지 뇌 백질 병변이 있어 본원에서 추적 검사 중인 환자 39명(남자 21명, 여자 18명, 평균연령 54.9세)을 대상으로 conventional 3D T1 MPRAGE와 wave- CAIPI R(reduction factor) 6(3 × 2), wave-CAIPI R(reduction factor) 4(2 × 2) 기법으로 영상을 획득하였다. 전신용 3.0T MRI(Skyra, SIEMENS, Erlangen, Germany), 64 channel head coil을 사 용하였고, 모든 sequence는 sagittal로 촬영하였으며 interpolation은 적용하지 않았다. Conventional 3D T1 MPRAGE의 scan parameter는 1 mm isotropic voxel, FOV: 256 mm, TR: 2500 ms, TE: 2.98 ms, TI: 1100 ms, PAT mode: GRAPPA, Accel. factor: PE 2였고, wave-CAIPI MPRAGE R6에서는 1 mm isotropic voxel, FOV: 256 mm, TR: 2500 ms, TE: 3.06 ms, TI: 1100 ms, PAT mode: CAIPIRINHA, Accel. factor: PE 3, 3D(slice) 2였으며, wave-CAIPI MPRAGE R4에서는 1 mm isotropic voxel, FOV: 256 mm, TR: 2500 ms, TE: 3.06 ms, TI: 1100 ms, PAT mode: CAIPIRINHA, Accel. factor: PE 2, 3D(slice)2였다. 획득한 영상은 medical image viewing solution(Terarecon, ver4.4.12, Foster City, USA)을 이용하여 axial reconstruction하였고, corona radiator, pons 그리고 cerebellar hemispheres에서 SNR과 CNR을 측정하였다. 정성적 평가 는 PACS(marotech, ver5.4.10.68, seoul, Korea)로 전송된 영상을 영상의학과 전문의 1명이 국소 병변에 대한 각 sequence 간의 진단능을 평가하였고, image quality는 영상의학과 전문의 1명과 MRI실 업무경력 10년 이상의 방사선사 1명이 blind test로 평가하였다. 정량적 평가의 통계적 검증은 Microsoft Excel 2010을 이용하여 ANOVA test를 하였다. 결 과：Conventional 3D T1 MPRAGE, wave-CAIPI R6 그리고 wave-CAIPI R4, 3개의 sequence 별로 측정한 SNR의 평균값은 Corona radiator에서 각각 160.08 ± 53.52, 185.56 ± 46.5 그리고 186.12 ± 48.44이었고, pons에서는 165.12 ± 43.41, 190.5 ± 46.24 그리고 190.94 ± 45.92이었으며, cerebellar hemispheres에서는 173.85 ± 52.67, 187.21 ± 52.13 그리고 191.92 ± 54.7이었다. Corona radiator 에서 GM(gray matter)과 WM(white matter)의 CNR 평균값은 conventional 3D T1 MPRAGE에서 52.39 ± 20.62였고 wave-CAIPI R6에서는 58.54 ± 18.32였으며 wave-CAIPI R4에서는 57.58 ± 21.11로 Conventional 3D T1 MPRAGE에 비해 wave-CAIPI R6, R4에서 SNR과 CNR이 약간 높았 다. 3 sequence 간의 focal lesion diagnosis에 대한 정성적 평가에서 100% agreement를 보였으며, image quality에 대한 평가에서 conventional 3D T1 MPRAGE에서 평균 4.85 ± 0.37, wave- CAIPI R6에서 3.82 ± 0.56, wave-CAIPI R4에서 4.10 ± 0.55 이었고 통계적 유의하였다(p≤0.05). 영상 획득 시간은 conventional 3D T1 MPRAGE는 5:48s였고 wave-CAIPI R6에서는 1:52s였으며 wave-CAIPI R4는 2:44s로, conventional 3D T1 MPRAGE에 비해 각각 67.8%, 52.8% 감소하였다. 결 론：Conventional 3D T1 MPRAGE에 비해 wave-CAIPI MPRAGE기법은 image quality의 저하 없이 scan time을 획기적으로 줄일 수 있어 임상적으로 유용할 것으로 사료된다.

목 적：New fast acquisition technique인 wave-CAIPIRINHA를 적용한 MPRAGE sequence를 통해 brain의 국소병 변 진단능과 화질의 변화를 알아보고자 한다. 대상 및 방법：2017년 11월 22일부터 2018년 1월 2일까지 뇌 백질 병변이 있어 본원에서 추적 검사 중인 환자 39명(남자 21명, 여자 18명, 평균연령 54.9세)을 대상으로 conventional 3D T1 MPRAGE와 wave-CAIPI R(reduction factor) 6(3 × 2), wave-CAIPI R 4(2 × 2) 기법으로 영상을 획득하였다. 전신용 3.0T MRI(Skyra, SIEMENS, Erlangen, Germany), 64 channel head coil을 사용하였고, 모든 sequence는 sagittal로 촬영하였으며 interpolation은 적용하지 않았다. Conventional 3D T1 MPRAGE의 scan parameter는 1 mm isotropic voxel, FOV: 256 mm, TR: 2500 ms, TE: 2.98 ms, TI: 1100 ms, PAT mode: GRAPPA, Accel. factor: PE 2였고, wave-CAIPI MPRAGE R6에서는 1 mm isotropic voxel, FOV: 256 mm, TR: 2500 ms, TE: 3.06 ms, TI: 1100 ms, PAT mode: CAIPIRINHA, Accel. factor: PE 3, 3D(slice) 2였으며, wave-CAIPI MPRAGE R4에서는 1 mm isotropic voxel, FOV: 256 mm, TR: 2500 ms, TE: 3.06 ms, TI: 1100 ms, PAT mode: CAIPIRINHA, Accel. factor: PE 2, 3D(slice)2였다. 획득한 영상은 medical image viewing solution(Terarecon, ver4.4.12, Foster City, USA)을 이용하여 axial reconstruction하였고, corona radiator, pons 그리고 cerebellar hemispheres에서 SNR과 CNR을 측정하였다. 정성적 평가는 PACS (marotech, ver5.4.10.68, seoul, Korea)로 전송된 영상을 영상의학과 전문의 1명이 국소 병변에 대한 각 sequence 간의 진단능을 평가하였고, image quality는 영상의학과 전문의 1명과 MRI실 업무경력 10년 이상의 방사선사 1명이 blind test로 평가하였다. 정량적 평가의 통계적 검증은 Microsoft Excel 2010을 이용하여 ANOVA test를 하였다. 결 과：Conventional 3D T1 MPRAGE, wave-CAIPI R6 그리고 wave-CAIPI R4, 3개의 sequence 별로 측정한 SNR의 평균값은 Corona radiator에서 각각 160.08 ± 53.52, 185.56 ± 46.5 그리고 186.12 ± 48.44이었고, pons에서는 165.12 ± 43.41, 190.5 ± 46.24 그리고 190.94 ± 45.92이었으며, cerebellar hemispheres에서는 173.85 ± 52.67, 187.21 ± 52.13 그리고 191.92 ± 54.7이었다. Corona radiator에서 GM(gray matter)과 WM(white matter)의 CNR 평균 값은 conventional 3D T1 MPRAGE에서 52.39 ± 20.62였고 wave-CAIPI R6에서는 58.54 ± 18.32였으며 wave-CAIPI R4에서는 57.58 ± 21.11로 Conventional 3D T1 MPRAGE에 비해 wave-CAIPI R6, R4에서 SNR과 CNR이 약간 높았 다. 3 sequence 간의 focal lesion diagnosis에 대한 정성적 평가에서 100% agreement를 보였으며, image quality에 대한 평가에서 conventional 3D T1 MPRAGE에서 평균 4.85 ± 0.37, wave-CAIPI R6에서 3.82 ± 0.56, wave-CAIPI R4에서 4.10 ± 0.55 이었고 통계적 유의하였다(p≤0.05). 영상 획득 시간은 conventional 3D T1 MPRAGE는 5:48s였고 wave-CAIPI R6에서는 1:52s였으며 wave-CAIPI R4는 2:44s로, conventional 3D T1 MPRAGE에 비해 각각 67.8%, 52.8% 감소하였다. 결 론：Conventional 3D T1 MPRAGE에 비해 wave-CAIPI MPRAGE기법은 image quality의 저하 없이 scan time을 획기적으로 줄일 수 있어 임상적으로 유용할 것으로 사료된다.

The use of complimentary indicators, other than radiation dose and risk, to assess the safety of radioactive waste disposal has been discussed in a number of publications for providing the reasonable assurance of disposal safety and convincing the public audience. In this study, the radionuclide flux was selected as performance indicator to appraise the performance of engineered barriers and natural barrier in the Wolsong low- and intermediate-level waste disposal facility. Radionuclide flux showing the retention capability by each compartment of the disposal system is independent of assumptions in biosphere model and exposure pathways. The scenario considered as the normal scenario of disposal facility has been divided into intact or degraded silo concrete conditions. In the intact silo concrete, the radionuclide flux has been assessed with respect to the radionuclide retardation performance of each engineered barrier. In the degraded silo concrete, the radionuclide flux has been explored based on the performance degradation of engineered barriers and the relative significance of natural barrier quantitatively. The results can be used to optimally design the near-surface disposal facility being planned as the second project phase. In the future, additional complimentary indicators will be employed for strengthening the safety case for improving the public acceptance of low- and intermediate-level waste disposal facility.

The low and intermediate-level radioactive waste generated in Korea is disposed of at Wolsong Disposal Facility. For the safety of a disposal facility, it must be assessed by considering some abnormal scenarios including human intrusion as well as those by natural phenomena. The human intrusion scenario is a scenario that an incognizant man of the disposal facility will be occurred by the drilling. In this paper, the well usage scenario was classified into the human intrusion event as the probability of the well drilling is very low during the man’s lifecycle and then was assessed by using conservative assumptions. This scenario was assessed using the dilution factor of contaminants released from a disposal facility and then it was introduced the applied methodology in this study. The assessed scenario using this methodology is satisfied the regulatory limits.

시판 유통 중인 고춧가루의 10종에 대해 미생물 (총 호 기성균수, 대장균군, 효모 & 곰팡이), 이화학적 품질 (수분 함량, pH, 기계적 색도 및 ASTA 색도, 입자 크기)을 확인 하였다. 시판 유통 중인 미생물 농도 측정결과, 총 호기성균, 효모 및 곰팡이는 103-106CFU/g 으로 나타났고, 대장 균군은 2종의 검체에서 103 CFU/g의 분포를 나타내었다. 수분함량은 7.25-12.73%로 나타나, 10종 모두 식품공전의 기준규격에 적합하였다. pH는 4.97~5.15 범위를 나타내어 시판 고춧가루의 건조방법은 각각 다른 것으로 판단되었다. 색도 측정결과 기계적 색도의 E 값은 최저 47.19, 최 고 58.04를 나타내었고, ASTA 색도는 최저 89.31, 최고 98.61로 나타나 제품별로 색도의 뚜렷한 차이가 나타났으나, 기계적 색도와 ASTA 색도의 상관성은 높지 않은 것으로 판단되었다. 고춧가루 10개 검체의 평균 입자크기는 605-1251 um로 나타났고, 분포도는 2종의 시료(RP-2, RP- 3)는 매우 균일한 분포도를 나타낸 반면, RP-9, RP-10은 가장 고르지 못한 분포도를 나타내었다.