In May 2018,the primetime news casted a shocking report saying that radon concentration on a certain model of bed mattress found to be as high as 2200 Bq/m3.After a humble,the Nuclear Safety and Security Commission(NS...In May 2018,the primetime news casted a shocking report saying that radon concentration on a certain model of bed mattress found to be as high as 2200 Bq/m3.After a humble,the Nuclear Safety and Security Commission(NSSC)of Korea confirmed that significant amount of thoron gas is emanated from several mattress models marketed by a company claiming beneficial health effects of negative ions.Laboratory analysis showed that some internal fabric sheets of those mattresses contain high concentration of Th-232.It was revealed that the manufacture treated the material with so-called‘negative ion powder’procured from the market and NSSC found that its radioactive content is the monazite powder.Although measurements with reliable instruments resulted in somewhat lower values,the tentative but conservative estimates of doses to the users are still remarkable,ranging from a few to 14 mSv a year.Most of the affected models have been marketed from 2010 but earlier models,with lower thorium content,were supplied from 2006.As many as 88,000 mattresses have been produced.The manufacturer with help of the government,recalled all the affected models and separated the radioactive internals.A large amount of waste is waiting for the government decision on disposal method.Similar problems were identified in other consumer products including latex mattresses and pillows imported,hot pads,and several models of sanitary or health-aid goods.These episodes called for revisiting NORM control strategy in Korea.展开更多
The impact of the radiation dose produced by^(222)Rn/^(220)Rn and its progeny on human health has garnered increasing interest in the nuclear research field.The establishment of robust,regulatory,and competent^(220)Rn...The impact of the radiation dose produced by^(222)Rn/^(220)Rn and its progeny on human health has garnered increasing interest in the nuclear research field.The establishment of robust,regulatory,and competent^(220)Rn chambers is crucial for accurately measuring radioactivity levels.However,studying the uniformity of the^(220)Rn progeny through experimental methods is challenging,because measuring the concentration of^(220)Rn and its progeny in multiple spatial locations simultaneously and in real time using experimental methods is difficult.Therefore,achieving precise control of the concentration of^(220)Rn and its progeny as well as the reliable sampling of the progeny pose significant challenges.To solve this problem,this study uses computational fluid dynamics to obtain the flow-field data of the^(220)Rn chamber under different wind speeds and progenyreplenishment rates.Qualitative analysis of the concentration distribution of the progeny and quantitative analysis of the progeny concentration and uniformity of the progeny concentration are conducted.The research findings indicated that the progeny concentration level is primarily influenced by wind speed and the progeny-complement rate.Wind speed also plays a crucial role in determining progeny concentration uniformity,whereas the progeny-complement rate has minimal impact on uniformity.To ensure the accuracy of^(220)Rn progeny concentration sampling,we propose a methodology for selecting an appropriate sampling area based on varying progeny concentrations.This study holds immense importance for enhancing the regulation and measurement standards of^(220)Rn and its progeny.展开更多
目的调查个旧地区居室内氡（^222Rn）、钍射气（^220Rn）及其子体水平，明确钍射气的剂量贡献。方法考虑住宅类型和地理分布因素，从个旧市郊某村选取建筑结构有代表性的50户住宅的主卧室，采用氡-钍射气鉴别探测器测量氡、钍射气浓度...目的调查个旧地区居室内氡（^222Rn）、钍射气（^220Rn）及其子体水平，明确钍射气的剂量贡献。方法考虑住宅类型和地理分布因素，从个旧市郊某村选取建筑结构有代表性的50户住宅的主卧室，采用氡-钍射气鉴别探测器测量氡、钍射气浓度，用沉积率装置测量钍射气子体浓度。其中14间居室采用连续性氡测量探测器和α谱氡、钍射气鉴别探测器测量氡、钍射气浓度，空气采样滤膜结合CR-39探测器测量钍射气衰变产物浓度，碘化钠闪烁计数器测量地表γ剂量率。结果50间居室的氡浓度为32～498Bq／m^3，平均136Bq／m^3；钍射气浓度为39～7908Bq／m^3，平均3297Bq／m^3；钍射气子体浓度为2．0～23．9Bq／m^3，平均10．2Bq／m^3。钍射气子体衰变产物致居民年平均有效剂量大于氡子体衰变产物的平均年有效剂量（2．9mSv vs 1．6mSv）。结论个旧市郊部分居室室内钍射气及其子体浓度高，钍射气子体的剂量贡献要高于氡子体的剂量贡献。在个旧开展氡致肺癌危险评价研究应当考虑钍射气子体的剂量贡献。展开更多
文摘In May 2018,the primetime news casted a shocking report saying that radon concentration on a certain model of bed mattress found to be as high as 2200 Bq/m3.After a humble,the Nuclear Safety and Security Commission(NSSC)of Korea confirmed that significant amount of thoron gas is emanated from several mattress models marketed by a company claiming beneficial health effects of negative ions.Laboratory analysis showed that some internal fabric sheets of those mattresses contain high concentration of Th-232.It was revealed that the manufacture treated the material with so-called‘negative ion powder’procured from the market and NSSC found that its radioactive content is the monazite powder.Although measurements with reliable instruments resulted in somewhat lower values,the tentative but conservative estimates of doses to the users are still remarkable,ranging from a few to 14 mSv a year.Most of the affected models have been marketed from 2010 but earlier models,with lower thorium content,were supplied from 2006.As many as 88,000 mattresses have been produced.The manufacturer with help of the government,recalled all the affected models and separated the radioactive internals.A large amount of waste is waiting for the government decision on disposal method.Similar problems were identified in other consumer products including latex mattresses and pillows imported,hot pads,and several models of sanitary or health-aid goods.These episodes called for revisiting NORM control strategy in Korea.
基金supported by the National Natural Science Foundation of China(Nos.12375310,12175102,and 118750356)Youth Talent Foundation of Hunan Province of China(2022TJQ16)Graduate Research and Innovation Projects of Hunan Province(CX20230964)。
文摘The impact of the radiation dose produced by^(222)Rn/^(220)Rn and its progeny on human health has garnered increasing interest in the nuclear research field.The establishment of robust,regulatory,and competent^(220)Rn chambers is crucial for accurately measuring radioactivity levels.However,studying the uniformity of the^(220)Rn progeny through experimental methods is challenging,because measuring the concentration of^(220)Rn and its progeny in multiple spatial locations simultaneously and in real time using experimental methods is difficult.Therefore,achieving precise control of the concentration of^(220)Rn and its progeny as well as the reliable sampling of the progeny pose significant challenges.To solve this problem,this study uses computational fluid dynamics to obtain the flow-field data of the^(220)Rn chamber under different wind speeds and progenyreplenishment rates.Qualitative analysis of the concentration distribution of the progeny and quantitative analysis of the progeny concentration and uniformity of the progeny concentration are conducted.The research findings indicated that the progeny concentration level is primarily influenced by wind speed and the progeny-complement rate.Wind speed also plays a crucial role in determining progeny concentration uniformity,whereas the progeny-complement rate has minimal impact on uniformity.To ensure the accuracy of^(220)Rn progeny concentration sampling,we propose a methodology for selecting an appropriate sampling area based on varying progeny concentrations.This study holds immense importance for enhancing the regulation and measurement standards of^(220)Rn and its progeny.
文摘目的调查个旧地区居室内氡（^222Rn）、钍射气（^220Rn）及其子体水平，明确钍射气的剂量贡献。方法考虑住宅类型和地理分布因素，从个旧市郊某村选取建筑结构有代表性的50户住宅的主卧室，采用氡-钍射气鉴别探测器测量氡、钍射气浓度，用沉积率装置测量钍射气子体浓度。其中14间居室采用连续性氡测量探测器和α谱氡、钍射气鉴别探测器测量氡、钍射气浓度，空气采样滤膜结合CR-39探测器测量钍射气衰变产物浓度，碘化钠闪烁计数器测量地表γ剂量率。结果50间居室的氡浓度为32～498Bq／m^3，平均136Bq／m^3；钍射气浓度为39～7908Bq／m^3，平均3297Bq／m^3；钍射气子体浓度为2．0～23．9Bq／m^3，平均10．2Bq／m^3。钍射气子体衰变产物致居民年平均有效剂量大于氡子体衰变产物的平均年有效剂量（2．9mSv vs 1．6mSv）。结论个旧市郊部分居室室内钍射气及其子体浓度高，钍射气子体的剂量贡献要高于氡子体的剂量贡献。在个旧开展氡致肺癌危险评价研究应当考虑钍射气子体的剂量贡献。
