국내 원전에서 발생되는 방사성폐기물은 중간 저장시설 운영에 대한 운반을 고려하여, 수송시 방사성물질 수송위험도 평가를 실시하여야 한다. 방사성물질 수송위험도 평가는 작업자 및 일반 주민에 대한 선량평가가 이루어져야 하고, 선량평가시 주민선량 평가는 해당 지역별 차폐계수에 따라 피폭 선량평가가 달라진다.
국외에서는 각 국가의 주거 환경에 맞추어 건축물 차폐계수를 산출하는 연구를 수행하였다. 이는 국가별로 ...
국내 원전에서 발생되는 방사성폐기물은 중간 저장시설 운영에 대한 운반을 고려하여, 수송시 방사성물질 수송위험도 평가를 실시하여야 한다. 방사성물질 수송위험도 평가는 작업자 및 일반 주민에 대한 선량평가가 이루어져야 하고, 선량평가시 주민선량 평가는 해당 지역별 차폐계수에 따라 피폭 선량평가가 달라진다.
국외에서는 각 국가의 주거 환경에 맞추어 건축물 차폐계수를 산출하는 연구를 수행하였다. 이는 국가별로 건축구조 형태 및 주거 밀집 형태, 그리고 구조재의 특성이 다르기 때문에 이에 따라 외부 선원으로부터의 피폭 선량평가가 달라지기 때문이다. 따라서, 본 연구에서는 국내 환경에 적합한 방사성물질 수송위험도 평가를 위한 지역별 차폐계수를 산출하는데 목적이 있다.
본 연구에서는 국내 가옥의 건축물 구조별로 차폐 구조를 설계 제작 후 해당 물질에 대한 중성자, 감마선 차폐실험을 실시하여 구조별 차폐율을 구하고, 실험값에 대한 타당성을 검증하기 위하여 몬테카를로 방법론을 이용하여 현상을 해석하는 전산코드 MCNP(Monte Carlo N-particle Transport Computer Code)를 사용하였다. 국내 가옥의 건축물 구조는 단일구조인 콘크리트 블록구조와 복합구조인 주택구조와 아파트구조로 분류하였다. 차폐실험에 사용된 선원은 14MeV의 고속중성자를 최대 2×108n/s 발생시키는 D-T(Deuterium Tritium type) 중성자 발생장치와 선량 9.5Ci인 이리듐-192(Ir-192)를 사용하였다. 각 실험은 선원별로 구조재의 조건에 따라 5회 이상 반복 측정 하였고, 측정된 값의 평균값을 사용하였다. MCNP 검증을 위하여 각 구조재의 물질별 성분비를 조사하여 실제 실험과 동일한 국내 가옥의 건축구조를 모사하였다.
본 연구를 통하여 향후 다양한 국내 건축 구조물에 대한 차폐율 산출에 보다 효율적인 방법으로 적용 가능하다. 연구 결과 국내 가옥구조는 주택구조가 아파트구조보다 1~3% 정도로 차폐율이 높게 나타남을 알 수 있었다. 그 이유는 아파트구조가 주택구조보다 벽체는 두꺼우나 주택구조에는 대부분 외부 벽이 밀도가 높은 적벽돌로 되어있어 차폐율이 더 높은 것으로 판단된다. 또한 실험결과를 기반으로 산출된 지역 특성별 중성자 차폐계수는 평균 0.584, 감마 차폐계수는 평균 0.866임을 알 수 있었다.
국내 원전에서 발생되는 방사성폐기물은 중간 저장시설 운영에 대한 운반을 고려하여, 수송시 방사성물질 수송위험도 평가를 실시하여야 한다. 방사성물질 수송위험도 평가는 작업자 및 일반 주민에 대한 선량평가가 이루어져야 하고, 선량평가시 주민선량 평가는 해당 지역별 차폐계수에 따라 피폭 선량평가가 달라진다.
국외에서는 각 국가의 주거 환경에 맞추어 건축물 차폐계수를 산출하는 연구를 수행하였다. 이는 국가별로 건축구조 형태 및 주거 밀집 형태, 그리고 구조재의 특성이 다르기 때문에 이에 따라 외부 선원으로부터의 피폭 선량평가가 달라지기 때문이다. 따라서, 본 연구에서는 국내 환경에 적합한 방사성물질 수송위험도 평가를 위한 지역별 차폐계수를 산출하는데 목적이 있다.
본 연구에서는 국내 가옥의 건축물 구조별로 차폐 구조를 설계 제작 후 해당 물질에 대한 중성자, 감마선 차폐실험을 실시하여 구조별 차폐율을 구하고, 실험값에 대한 타당성을 검증하기 위하여 몬테카를로 방법론을 이용하여 현상을 해석하는 전산코드 MCNP(Monte Carlo N-particle Transport Computer Code)를 사용하였다. 국내 가옥의 건축물 구조는 단일구조인 콘크리트 블록구조와 복합구조인 주택구조와 아파트구조로 분류하였다. 차폐실험에 사용된 선원은 14MeV의 고속중성자를 최대 2×108n/s 발생시키는 D-T(Deuterium Tritium type) 중성자 발생장치와 선량 9.5Ci인 이리듐-192(Ir-192)를 사용하였다. 각 실험은 선원별로 구조재의 조건에 따라 5회 이상 반복 측정 하였고, 측정된 값의 평균값을 사용하였다. MCNP 검증을 위하여 각 구조재의 물질별 성분비를 조사하여 실제 실험과 동일한 국내 가옥의 건축구조를 모사하였다.
본 연구를 통하여 향후 다양한 국내 건축 구조물에 대한 차폐율 산출에 보다 효율적인 방법으로 적용 가능하다. 연구 결과 국내 가옥구조는 주택구조가 아파트구조보다 1~3% 정도로 차폐율이 높게 나타남을 알 수 있었다. 그 이유는 아파트구조가 주택구조보다 벽체는 두꺼우나 주택구조에는 대부분 외부 벽이 밀도가 높은 적벽돌로 되어있어 차폐율이 더 높은 것으로 판단된다. 또한 실험결과를 기반으로 산출된 지역 특성별 중성자 차폐계수는 평균 0.584, 감마 차폐계수는 평균 0.866임을 알 수 있었다.
In this study, the shielding rate of Gamma-ray in the Korean-style building structure was calculated through verification by Experiment of Gamma-ray shielding and MNCP modeling. The shielding experiment of Gamma-ray source, Ir-192(Iridium), was performed manufacturing the structural walls of Housing...
In this study, the shielding rate of Gamma-ray in the Korean-style building structure was calculated through verification by Experiment of Gamma-ray shielding and MNCP modeling. The shielding experiment of Gamma-ray source, Ir-192(Iridium), was performed manufacturing the structural walls of Housing and Apartment which are the types of Korean House Architecture. The experiment on ferroconcretes with 15cm, 20cm and 25cm in width of each house structure was carried out on thickness and MNCP modeling was done to check the validity of experiment. The result of comparing each data with each other and analyzing it showed that housing displayed the shielding rate higher by 1~3% than apartment in the house structure of our country.
For Transportation risk assessment of Radioactive Materials generated from nuclear power plants in Korea, assessment of radiation dose to worker and citizens should be carried out considering transportation of the materials in operating intermediate storage for radioactive wastes. For assessment of radiation dose, exposure dose assessment depends on regional shielding coefficient. In foreign countries, the study of calculating each shielding coefficient according to living environment of each country was performed because each nation has its own characteristic of structural material and type of building structure and residential density, which indicates that assessment of exposure dose from external source is different from country to country. For United States, the values of shielding coefficient under regional conditions were calculated for assessment of exposure dose to residents in transportation route during transportation of radiation materials or accidents in nuclear power plants. Even before 1980s, the values have been calculated in the US. For Europe, the studies of calculating this value were performed from mid 1980s to early 1990s. For countries except US and Europe, they were carried out in the 1990s.
The common program used today for assessment of radiation impact during radioactive materials transportation, RADTRAN, is designed to calculate shielding coefficients under exposure conditions to assess the exposure dose from radiation emitted from surfaces of transportation container or tool. Regional shielding coefficients are generally classified as urban, suburban and rural and differently applied to each region. Shielding Coefficient presented from RADTRAN is 'Values are from Madsen' by Wilmot and Taylor (1986). It was presented that there is no shielding of radiation in rural environment and suburban environment has 13% of shielding effect on radiation. This reflects that building structure in suburban environment is considered structure made of wood. It was also suggested that 99.982% of radiation is shielded from urban environment, which indicates that buildings in urban environment are concrete structures with 1 feet high or higher.
There are also some studies presenting detailed coefficients of building structures besides calculation results of regional shielding coefficients. Unlike the studies of calculating shielding coefficient on each area characteristic centering on external wall, the types of structures and structural materials from underground to rooftop of general building structure were analyzed in these studies. Then, each characteristic shielding coefficient was calculated. In the US, shielding coefficient was calculated considering wood or concrete structures. In the Europe, however, the coefficient was counted with stone structures. This indicates it was considered that there are many buildings built many centuries ago there. In Brazil, shielding board was designed and manufactured considering external wall with multi-layer structure. It was considered that clay bricks are placed in the cement structures in housing structure of Brazil.
This study aimed at analyzing residential environment in Korea and calculating shielding coefficient of corresponding radiation material after designing and manufacturing shielding structure reflecting characteristic of Korean-style building structure.
9.5Ci of Ir-192 was used as the source of Gamma-ray, with using 0.317MeV of Gamma Energy for carrying out experiment of Gamma-ray shielding on Korean-style building structures. Like Table.1 and Fig 1, specimens of housing and apartment in Korean House structure were made with 40mm in height and 50mm in area and with ferroconcretes with 15cm, 20cm and 25cm in thickness manufactured respectively. The thickness of insulator used in the structures in the apartment was fixed to be 50mm. The thickness values of insulator on types and regions were used from standard table of thickness of insulator in Regulation for Facility in Building. For setting wall thickness, the external wall thickness is set to be 20cm, in case of apartment with more than 5 floors and building with more than 5 floors according to regulation of designing structure of Ministry of Land, Transport and Maritime Affairs. For Housing, basic plate was made of ferroconcrete according to Regulation for Facility in Building and the thickness of basic wall was set to be more than 250mm. For Housing made with Masonry Construction Brick, Walls consist of bearing wall, insulator and decorated wall and standard thickness of wall is 35mm. But, walls in 20~25mm of thickness are used. It is supposed that decorated wall is laid through using basic wall with 190mm in length, 90mm in width and 57mm in thickness and laying half of wall (0.5B). Then, thickness of red brick walls and insulator is fixed to be 90mm and 50mm (like the case of apartment), respectively.
In this experiment, Background was measured and then the value of radiation dose under no shielding condition. Then, Gamma-ray shielding experiment was performed according to the building structures comparing with the value of radiation dose under each condition of structural material.
The result of Gamma-ray shielding experiment under each condition of structural material in the Korean-style house structure and MNCP modeling. MCNP Outputdml mean was calculated using f6* tally, with jerk/g mean unit(1 jerk= 1.0*E+9). This value was obtained with unit conversion and multiplication of weighted value of radiation by radioactive strength. Blank means no shielding condition, Concrete does single structure according to ferroconcrete thickness, Housing does housing structure on each thickness of ferroconcrete and Apartment does apartment structure on each thickness of ferroconcrete. As shown in Table 3, it was found that there is similarity between experimental data and MCNP in the shielding rate under each condition of structural material.
This study aimed at calculating the shielding coefficient of Gamma-ray suitable for Korean Environment and analyzing Korean House structure. The shielding coefficients of Housing and Apartment reflecting the characteristic of building structure in Korea were calculated. Housing displayed measured shielding rate higher by 1~3% than Apartment. It is considered as the reason that Apartment has the thicker wall than Housing, but Housing has high-density red brick on external wall to have higher shielding rate than Apartment. Also, for shielding coefficient on regional characteristics calculated, shielding coefficient on urban environment is similar to that on suburban one. Also, the shielding rate on Housing is similar to that on Apartment, so it is considered that building structure makes almost no difference in shielding rate. It was shown that the shielding rate of Gamma-ray based on experimental result was 0.866.
The program for radioactive materials transportation risk assessment which was developed in US, RADTRAN, is also designed to calculate the values of shielding coefficient on regions and apply the value to each region. A Variety of programs for environmental effect assessment are also designed to calculate the shielding rate of region where accident happens and apply the value to each area. Therefore, each country calculates regional shielding coefficient suitable for its own environment to apply the value to the area in the country. For US, urban residential type is in clear distinction from suburban one. For urban area, Buildings made with ferroconcrete stand close together and the time for indoor activities is longer than that for outdoor ones. These urban characteristics in the US are similar to that in our country. For rural area, however, there are simple structures and time for outdoor activities is longer than that for indoor ones. Therefore, the difference in residential type and activity characteristic definitely classified according to regional characteristic in RADTRAN greatly changes the value of shielding coefficient. In this study, however, the result of collecting literary data shows that structures made with ferroconcrete or concrete hold a large majority of buildings and there is no significant difference between indoor activity time and outdoor one. Only, For US, exposure assessment is performed reflecting building density in the region as well as the type of certain building. In this study, however, shielding coefficient is set only considering the type of certain building. This indicates that recalculation of shielding coefficient as the reasonable value is possible by generally analyzing the cases of setting the shielding coefficients in other countries as well as United States in the future.
In this study, the shielding rate of Gamma-ray in the Korean-style building structure was calculated through verification by Experiment of Gamma-ray shielding and MNCP modeling. The shielding experiment of Gamma-ray source, Ir-192(Iridium), was performed manufacturing the structural walls of Housing and Apartment which are the types of Korean House Architecture. The experiment on ferroconcretes with 15cm, 20cm and 25cm in width of each house structure was carried out on thickness and MNCP modeling was done to check the validity of experiment. The result of comparing each data with each other and analyzing it showed that housing displayed the shielding rate higher by 1~3% than apartment in the house structure of our country.
For Transportation risk assessment of Radioactive Materials generated from nuclear power plants in Korea, assessment of radiation dose to worker and citizens should be carried out considering transportation of the materials in operating intermediate storage for radioactive wastes. For assessment of radiation dose, exposure dose assessment depends on regional shielding coefficient. In foreign countries, the study of calculating each shielding coefficient according to living environment of each country was performed because each nation has its own characteristic of structural material and type of building structure and residential density, which indicates that assessment of exposure dose from external source is different from country to country. For United States, the values of shielding coefficient under regional conditions were calculated for assessment of exposure dose to residents in transportation route during transportation of radiation materials or accidents in nuclear power plants. Even before 1980s, the values have been calculated in the US. For Europe, the studies of calculating this value were performed from mid 1980s to early 1990s. For countries except US and Europe, they were carried out in the 1990s.
The common program used today for assessment of radiation impact during radioactive materials transportation, RADTRAN, is designed to calculate shielding coefficients under exposure conditions to assess the exposure dose from radiation emitted from surfaces of transportation container or tool. Regional shielding coefficients are generally classified as urban, suburban and rural and differently applied to each region. Shielding Coefficient presented from RADTRAN is 'Values are from Madsen' by Wilmot and Taylor (1986). It was presented that there is no shielding of radiation in rural environment and suburban environment has 13% of shielding effect on radiation. This reflects that building structure in suburban environment is considered structure made of wood. It was also suggested that 99.982% of radiation is shielded from urban environment, which indicates that buildings in urban environment are concrete structures with 1 feet high or higher.
There are also some studies presenting detailed coefficients of building structures besides calculation results of regional shielding coefficients. Unlike the studies of calculating shielding coefficient on each area characteristic centering on external wall, the types of structures and structural materials from underground to rooftop of general building structure were analyzed in these studies. Then, each characteristic shielding coefficient was calculated. In the US, shielding coefficient was calculated considering wood or concrete structures. In the Europe, however, the coefficient was counted with stone structures. This indicates it was considered that there are many buildings built many centuries ago there. In Brazil, shielding board was designed and manufactured considering external wall with multi-layer structure. It was considered that clay bricks are placed in the cement structures in housing structure of Brazil.
This study aimed at analyzing residential environment in Korea and calculating shielding coefficient of corresponding radiation material after designing and manufacturing shielding structure reflecting characteristic of Korean-style building structure.
9.5Ci of Ir-192 was used as the source of Gamma-ray, with using 0.317MeV of Gamma Energy for carrying out experiment of Gamma-ray shielding on Korean-style building structures. Like Table.1 and Fig 1, specimens of housing and apartment in Korean House structure were made with 40mm in height and 50mm in area and with ferroconcretes with 15cm, 20cm and 25cm in thickness manufactured respectively. The thickness of insulator used in the structures in the apartment was fixed to be 50mm. The thickness values of insulator on types and regions were used from standard table of thickness of insulator in Regulation for Facility in Building. For setting wall thickness, the external wall thickness is set to be 20cm, in case of apartment with more than 5 floors and building with more than 5 floors according to regulation of designing structure of Ministry of Land, Transport and Maritime Affairs. For Housing, basic plate was made of ferroconcrete according to Regulation for Facility in Building and the thickness of basic wall was set to be more than 250mm. For Housing made with Masonry Construction Brick, Walls consist of bearing wall, insulator and decorated wall and standard thickness of wall is 35mm. But, walls in 20~25mm of thickness are used. It is supposed that decorated wall is laid through using basic wall with 190mm in length, 90mm in width and 57mm in thickness and laying half of wall (0.5B). Then, thickness of red brick walls and insulator is fixed to be 90mm and 50mm (like the case of apartment), respectively.
In this experiment, Background was measured and then the value of radiation dose under no shielding condition. Then, Gamma-ray shielding experiment was performed according to the building structures comparing with the value of radiation dose under each condition of structural material.
The result of Gamma-ray shielding experiment under each condition of structural material in the Korean-style house structure and MNCP modeling. MCNP Outputdml mean was calculated using f6* tally, with jerk/g mean unit(1 jerk= 1.0*E+9). This value was obtained with unit conversion and multiplication of weighted value of radiation by radioactive strength. Blank means no shielding condition, Concrete does single structure according to ferroconcrete thickness, Housing does housing structure on each thickness of ferroconcrete and Apartment does apartment structure on each thickness of ferroconcrete. As shown in Table 3, it was found that there is similarity between experimental data and MCNP in the shielding rate under each condition of structural material.
This study aimed at calculating the shielding coefficient of Gamma-ray suitable for Korean Environment and analyzing Korean House structure. The shielding coefficients of Housing and Apartment reflecting the characteristic of building structure in Korea were calculated. Housing displayed measured shielding rate higher by 1~3% than Apartment. It is considered as the reason that Apartment has the thicker wall than Housing, but Housing has high-density red brick on external wall to have higher shielding rate than Apartment. Also, for shielding coefficient on regional characteristics calculated, shielding coefficient on urban environment is similar to that on suburban one. Also, the shielding rate on Housing is similar to that on Apartment, so it is considered that building structure makes almost no difference in shielding rate. It was shown that the shielding rate of Gamma-ray based on experimental result was 0.866.
The program for radioactive materials transportation risk assessment which was developed in US, RADTRAN, is also designed to calculate the values of shielding coefficient on regions and apply the value to each region. A Variety of programs for environmental effect assessment are also designed to calculate the shielding rate of region where accident happens and apply the value to each area. Therefore, each country calculates regional shielding coefficient suitable for its own environment to apply the value to the area in the country. For US, urban residential type is in clear distinction from suburban one. For urban area, Buildings made with ferroconcrete stand close together and the time for indoor activities is longer than that for outdoor ones. These urban characteristics in the US are similar to that in our country. For rural area, however, there are simple structures and time for outdoor activities is longer than that for indoor ones. Therefore, the difference in residential type and activity characteristic definitely classified according to regional characteristic in RADTRAN greatly changes the value of shielding coefficient. In this study, however, the result of collecting literary data shows that structures made with ferroconcrete or concrete hold a large majority of buildings and there is no significant difference between indoor activity time and outdoor one. Only, For US, exposure assessment is performed reflecting building density in the region as well as the type of certain building. In this study, however, shielding coefficient is set only considering the type of certain building. This indicates that recalculation of shielding coefficient as the reasonable value is possible by generally analyzing the cases of setting the shielding coefficients in other countries as well as United States in the future.
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