• Nuclear Engineering and Technology
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• 제49권8호
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• pp.1752-1757
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• 2017

The aim of this study is to evaluate the radioactivity levels and radiological impacts of representative black sand samples collected from different locations in the Rashid area, Egypt. These samples were prepared and then analyzed using the high-resolution gamma ray spectroscopy technique with a high-purity germanium detector. The activity concentration ($A_c$), minimum detectable activity, absorbed gamma dose rate, external hazard index ($H_{ex}$), annual effective dose rate equivalent, radium equivalent, as well as external and internal hazard index ($H_{ex}$ and $H_{in}$, respectively) were estimated based on the measured radionuclide concentration of the $^{238}U$($^{226}Ra$) and $^{232}Th$ decay chains and $^{40}K$. The activity concentrations of the $^{238}U$, $^{232}Th$ decay series and $^{40}K$ of these samples varied from $45.11{\pm}3.1Bq/kg$ to $252.38{\pm}34.3Bq/kg$, from $64.65{\pm}6.1Bq/kg$ to $579.84{\pm}53.1Bq/kg$, and from $403.36{\pm}20.8Bq/kg$ to $527.47{\pm}23.1Bq/kg$, respectively. The activity concentration of $^{232}Th$ in Sample 1 has the highest value compared to the other samples; this value is also higher than the worldwide mean range as reported by UNSCEAR 2000. The total absorbed gamma dose rate and the annual effective dose for these samples were found to vary from 81.19 nGy/h to 497.81 nGy/h and from $99.86{\mu}Sv/y$ to $612.31{\mu}Sv/y$, which are higher than the world average values of 59 nGy/h and $70{\mu}Sv/y$, respectively. The $H_{ex}$ values were also calculated to be 3.02, 0.47, 0.63, 0.87, 0.87, 0.51 and 0.91. It was found that the calculated value of $H_{ex}$ for Sample 1 is significantly higher than the international acceptable limit of <1. The results are tabulated, depicted, and discussed within national and international frameworks, levels, and approaches.

• Journal of Radiation Protection and Research
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• 제15권2호
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• pp.87-100
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• 1990

자연환경 방사선의 주 요소의 하나인 지각 방사선에 의한 피폭선량을 정량적으로 측정 해석하기 위하여 24개월간에 걸친 TLD에 의한 연속 적산선량 측정과 주기적인 감마선 분광분석을 수행하였다. TLD로는 LiF PTFE disk형을 사용하였으며 감마선 분광분석에서는 $3&{\phi}{\times}3'$원주형 Nal(Tl) 섬광검출기와 휴대형 다중파고 분석기 (4096 ch)를 사용하였다. 측정한 선량은 모두 실효 선량당량으로 평가하였으며 부수적으로 우주선 전리 성분에 의한 선량당량도 평가할 수 있었다. 분산 가중 평균값을 취한 결과에 의하면 대전 지역의 측정점에서 지각 방사선과 우주선 전리 성부의 체외 피폭에 의한 년간 실효 선량당량은 각각 $564{\pm}4\;{\mu}Sv(64.8{\pm}0.5nSv{\cdot}h^{-1}$ 및 $300{\pm}2\;{\mu}Sv(34.3{\pm}0.2nSv{\cdot}h^{-1}$로 나타났다.

• Journal of Radiation Protection and Research
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• 제41권4호
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• pp.424-435
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• 2016

Background: The International Commission on Radiological Protection (ICRP) recommendations and the Federal Guidance Report (FGR) published by the U.S. Environmental Protection Agency (EPA) have been widely applied worldwide in the fields of radiation protection and dose assessment. The dose conversion coefficients of the ICRP and FGR are widely used for assessing exposure doses. However, before the coefficients are used, the user must thoroughly understand the derivation process of the coefficients to ensure that they are used appropriately in the evaluation. Materials and Methods: The ICRP provides recommendations to regulatory and advisory agencies, mainly in the form of guidance on the fundamental principles on which appropriate radiological protection can be based. The FGR provides federal and state agencies with technical information to assist their implementation of radiation protection programs for the U.S. population. The system of radiation dose assessment and dose conversion coefficients in the ICRP and FGR is reviewed in this study. Results and Discussion: A thorough understanding of their background is essential for the proper use of dose conversion coefficients. The FGR dose assessment system was strongly influenced by the ICRP and the U.S. National Council on Radiation Protection and Measurements (NCRP), and is hence consistent with those recommendations. Moreover, the ICRP and FGR both used the scientific data reported by Biological Effects of Ionizing Radiation (BEIR) and United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) as their primary source of information. The difference between the ICRP and FGR lies in the fact that the ICRP utilized information regarding a population of diverse races, whereas the FGR utilized data on the American population, as its goal was to provide guidelines for radiological protection in the US. Conclusion: The contents of this study are expected to be utilized as basic research material in the areas of radiation protection and dose assessment.

• Nuclear Engineering and Technology
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• 제52권10호
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• pp.2370-2378
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• 2020

Building materials contribute significantly to the indoor radon and thoron levels. Therefore, parameters that influence the exhalation rates of radon and thoron from building material need to be analyzed closely. As a preliminary study, the effects of humidity on exhalation rates were measured using a system with an accumulation chamber and RAD7 detector for Korean brick, Korean soil, and Indonesian brick. Resulting doses to a person who resides in a room constructed from the building materials were assessed by UNSCEAR method for different air exchange rates. The measurements have revealed that Korean brick exhaled the highest radon and thoron while Indonesian brick exhaled the lowest thoron. Results showed that for a typical low dense material, radon and thoron exhalation rate will increase until reached its maximum at a certain value of humidity and will remain saturated above it. Analysis on concentration and effective dose showed that radon is strongly affected by air exchange rate (ACH). This is showed by about 66 times decrease of radon dose from 0.00 h^-1 to those of 0.50 h^-1 ACH and decrease by a factor of 2 from 0.50 h^-1 to those of 0.80 h^-1. In case of thoron, the ACH doesn't have significant effects on effective dose.

• Nuclear Engineering and Technology
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• 제55권7호
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• pp.2447-2453
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• 2023

The radioactivity concentrations of Naturally Occurring Radioactive Materials (NORM) i.e., ²²⁶Ra, ²³²Th, and ⁴K in various chemical fertilizers being used in the agricultural soil of Pakistan were determined utilizing gamma spectrometry by employing a High Purity Germanium (HPGe) detector. The radioactivity concentrations of ²²⁶Ra, ²³²Th, and ⁴K extended from 2.58 ± 0.8-265.7 ± 8.8 Bq kg^-1, 1.53 ± 0.14-76.6 ± 1.07 Bq kg^-1 and 36.5 ± 1.34-15606.7 ± 30.2 Bq kg^-1 respectively. The radiological hazard parameters such as internal and external indices and annual effective dose rates were calculated, while excessive lifetime cancer risk factors for the indoor and outdoor areas were found in the range from 0.3×10^-3 to 10.723×10^-3 and 0.03×10^-3 to 2.7948×10^-3 of most fertilizers, however, some values were slightly higher than the UNSCEAR (The United Nations Scientific Committee on the Effects of Atomic Radiation) recommended values for potash-containing fertilizers such as MOP (Muriate of Potash).

• Nuclear Engineering and Technology
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• 제56권1호
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• pp.207-215
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• 2024

This study focuses on measuring the levels of naturally occurring radioactivity in the soil of Swabi, Khyber Pakhtunkhwa, Pakistan, as well as the associated health hazard. Thirty (30) soil samples were collected from various locations and analyzed for ²²⁶Ra, ²³²Th, and ⁴⁰K radioactivity levels using a High Purity Germanium detector (HPGe) gamma-ray spectrometer with a photo-peak efficiency of approximately 52.3%. The average values obtained for these radionuclides are 35.6 ± 5.7 Bqkg^-1, 47 ± 12.5 Bqkg^-1, and 877 ± 153 Bqkg^-1, respectively. The level of ²³²Th is slightly higher and ⁴⁰K is 2.2 times higher than the internationally recommended limit of 30 Bqkg^-1 and 400 Bqkg^-1, respectively. Various parameters were calculated based on the results obtained, including Radium Equivalent (Ra_eq), External Hazard (H_ex), Absorbed Dose Rate (D), Annual Gonadal Equivalent Dose (AGDE), Annual Effective Dose Rate, and Excess Lifetime Cancer Risk (ELCR), which are 170.3 ± 24 Bqkg^-1, 0.46 ± 0.06 Bqkg^-1, 81.4 ± 2.04 nGy h^-1, 582 ± 78.08 µSvy^-1, 99.8 ± 13.5 µSv Gy^-1, and 0.349 ± 0.04, respectively. These values are below the limits recommended by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) in 2002. This study highlights the potential radiation threats associated with natural radioactivity levels in the soil of Swabi and provides valuable information for public health and safety.

• Journal of Radiation Protection and Research
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• 제39권3호
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• pp.142-149
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• 2014

한국은 국가건강검진을 시행하여 국민건강증진에 크게 기여하고 있으며 그 수검률 또한 증가하고 있다. 본 연구는 수검률 증가에 따른 방사선검사의 증가가 예상되어 그 이용 빈도(이용량)와 피폭선량을 파악하고자 한다. 본 연구는 2011년 국민건강보험공단 건강검진 분석 자료에서 방사선검사를 분리하여 이용량을 파악하고, UNSCEAR 2008년 보고서의 수록되어 있는 검사별 선량을 적용하여 국가건강검진에서 방사선검사로 인한 피폭선량을 추정한다. 주요 분석결과 2011년 국가건강검진 수검자 1인당 평균 피폭선량은 0.57 mSv로 추정되었고, 최대 11.081 mSv, 최소 0.02 mSv로 추정되었다. 방사선검사의 이용 빈도와 피폭선량은 각각 총 16,005,914건, 6,311.76 person-Sv로, 이중 이용량은 흉부 X선검사가 1,070,569 (69.17%)건으로 가장 높았고, 피폭선량은 위장조영검사가 5,217.94 (82.67%) person-Sv로 가장 높았다. 성 연령별 결과 39세 이하를 제외한 전 연령대에서 여성의 수검비율과 피폭선량이 높았고, 특히 50-54세 여성이 1,674,787 (10.5%)건, 701.59 (11.1%) person-Sv로 가장 높았다. 검사별 선량에서 위장조영검사가 전체 82.67%를 차지하는 만큼 의료상(목적) 반드시 시행하는 경우를 제외하고는 위장내시경검사를 선택하여 수검 받도록 정책적으로 장려하고 외국의 사례와 같이 경제성과 실효성 평가에 따라 폐지된다면 국가건강검진에의 방사선피폭은 현저히 줄어들 것으로 예상한다.

• Journal of Radiation Protection and Research
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• 제47권4호
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• pp.237-245
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• 2022

Background: The current study reports measurements of activity concentrations of radon (²²⁰Rn) and thoron (²²⁰Rn) in dwellings, followed by inhalation dose assessment of the public, and then by the development of regulation and the national radon action plan (NRAP) in Cameroon. Materials and Methods: Radon, thoron, and thoron progeny measurements were carried out from 2014 to 2017 using radon-thoron discriminative detectors (commercially RADUET) in 450 dwellings and thoron progeny monitors in 350 dwellings. From 2019 to 2020, radon track detectors (commercially RADTRAK) were deployed in 1,400 dwellings. It was found that activity concentrations of radon range in 1,850 houses from 10 to 2,620 Bq/㎥ with a geometric mean of 76 Bq/㎥. Results and Discussion: Activity concentrations of thoron range from 20 to 700 Bq/㎥ with a geometric mean of 107 Bq/㎥. Thoron equilibrium factor ranges from 0.01 to 0.6, with an arithmetic mean of 0.09 that is higher than the default value of 0.02 given by UNSCEAR. On average, 49%, 9%, and 2% of all surveyed houses have radon concentrations above 100, 200, and 300 Bq/㎥, respectively. The average contribution of thoron to the inhalation dose due to radon and thoron exposure is about 40%. Thus, thoron cannot be neglected in dose assessment to avoid biased results in radio-epidemiological studies. Only radon was considered in the drafted regulation and in the NRAP adopted in October 2020. Reference levels of 300 Bq/㎥ and 1,000 Bq/㎥ were recommended for dwellings and workplaces. Conclusion: Priority actions for the coming years include the following: radon risk mapping, promotion of a protection policy against radon in buildings, integration of the radon prevention and mitigation into the training of construction specialists, mitigation of dwellings and workplaces with high radon levels, increased public awareness of the health risks associated with radon, and development of programs on the scientific and technical aspects.