• Advances in materials Research
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• 제3권2호
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• pp.61-75
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• 2014

This study aimed to investigate the suitability of some concrete components for producing "high-performance heavy density concrete" using different types of aggregates that could enhances the shielding efficiency against ${\gamma}$-rays. 15 mixes were prepared using barite, magnetite, goethite and serpentine aggregates along with 10% silica fume, 20% fly ash and 30% blast furnace slag to total OPC content for each mix. The mixes were subjected to compressive strength at 7, 28 and 90 days. In some mixes, compressive strengths were also tested up to 90 days upon replacing sand with the fine portions of magnetite, barite and goethite. The mixes containing magnetite along with 10% SF reaches the highest compressive strength exceeding over M60 requirement by 14% after 28 days. Whereas, the compressive strength of concrete containing barite was very close to M60 and exceeds upon continuing for 90 days. Also, the compressive strength of high-performance concrete incorporating magnetite fine aggregate was significantly higher than that containing sand by 23%. On the other hand, concrete made with magnetite fine aggregate had higher physico-mechanical properties than that containing barite and goethite. High-performance concrete incorporating magnetite fine aggregate enhances the shielding efficiency against ${\gamma}$-rays.

• Nuclear Engineering and Technology
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• 제52권11호
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• pp.2607-2612
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• 2020

The present work was aimed to show the possibility of using hydrogel (acrylic/boric acid) for evaluation of the neutron radiation shielding. The influence of acrylic acid concentration, different gamma doses and relative contents of boric acid were studied. The physical properties and the thermomechanical stability of the studied samples were investigated. The shielding property of the composite for neutron was tested by Pu-Be neutron source (5 Ci) under room temperature. The neutron fluence rates and gamma fluxes were measured using a stilbene organic scintillator. The macroscopic effective removal cross-section Σ_R (cm^-1) of fast neutrons and total attenuation coefficient μ (cm^-1) of gamma rays has been studied experimentally. The transmission parameters, the relaxation length (??) and the half-value layer (HVL) were obtained. The obtained results indicated that the addition of boric acid to acrylic acid tends to increase the macroscopic effective removal cross-section Σ_R (cm^-1) to 0.141 compared to 0.094 of ordinary concrete.

• Journal of Radiation Protection and Research
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• 제3권1호
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• pp.29-32
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• 1978

감마선을 방출(放出)하는 방사성발기물(放射性發棄物)드럼 5292개($42{\times}42{\times}3$) 저장시설(貯藏施設)의 적정(適正) 콘크리트 차폐체(遮蔽體) 두께를 산출(算出)하였다. 발기물(發棄物)이 여러가지 종류(種類)의 방사성원소(放射性元素)로 구성(構成)되어 있다고 할때 평균(平均)한 감마선 에너지와 개개(個個) 감마선 에너지에 대하여 계산(計算)한 결과(結果)를 서로 비교(比較)하였다. 그 결과(結果) 적정차폐체(適正遮蔽體)의 두께는 50cm 정도(程度)로 판명(判明)되었다. 그런데 평균(平均) 감마선 에너지에 근거(根據)하여 계산(計算)한 선량치(線量値)는 개개(個個) 감마선 에너지에 대한 값보다 동일(同一)두께의 차폐체(遮蔽體)에 대해서 훨씬 적었다.

• Nuclear Engineering and Technology
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• 제50권8호
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• pp.1364-1371
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• 2018

An extensive investigation of photon interaction properties has been made for $Zn_xTe_{100-x}$ alloys (where x = 5, 20, 30, 40, 50) to explore its possible use in sensing and shielding gamma radiations. The results show better and stable response of ZnTe alloys for various photon interaction properties over the wide energy range, with an additional benefit of ease in fabrication due to lower melting points of Zn and Te. Mass attenuation coefficient values show strong dependence on photon energy as well as composition. Effective atomic number has maximum value for $Zn_5Te_{95}$ and lowest for $Zn_{50}Te_{50}$ in the entire energy region. The alloy sample with maximum $Z_{eff}$ shows minimal value of $N_e$ and vice versa. Mean free path follows inverse trend as observed for mass attenuation coefficient. The exposure and energy absorption buildup factors depend upon photon energy, penetration thickness and composition (effective atomic number) of $Zn_xTe_{100-x}$ alloys. It finds its application for sensing and shielding from highly energetic and highly penetrating photons at sites where radioactive materials were used and visibility of material is not a big constraint. Further, energy down conversion property of ZnTe alloys with subsequent emission in green band suggests its potential use in sensing gamma photons.

• Nuclear Engineering and Technology
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• 제55권2호
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• pp.690-695
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• 2023

Recommendations are given to improve the efficiency of radiation protection of transport casks for SNF transportation. The attenuation of ${\gamma}$-quanta of long-lived isotopes ¹³⁴Cs, ^137mBa(¹³⁷Cs), ¹⁵⁴Eu and ⁶⁰Co by optimizing the thicknesses and arrangement of layers of Fe and Pb radiation shields of transport casks is studied. The fixed radiation shielding mass (fixed mass thickness) is chosen as the main optimization criterion. The effect of the placement order of Fe and Pb layers in a combined two-layer radiation shield with an equivalent thickness of 30 cm is studied in detail. It is shown that with the same mass thicknesses of the Fe and Pb layers, the placement of Fe in the first layer, and Pb - in the second one provides more than twofold attenuation of ${\gamma}$-quanta compared to the reverse placement: Pb - in the first layer, Fe - in the second. The increase in the efficiency of attenuation of ${\gamma}$-quanta for TC with combined shielding of Fe and Pb is shown to be achieved by designing the first layer of radiation shielding around the canister with SNF from Fe of the maximum possible thickness.

• 대한방사선기술학회지:방사선기술과학
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• 제30권3호
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• pp.245-250
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• 2007

진단용 방사선발생장치에서의 X선 에너지와 $^{99m}Tc$-MDP, $^{18}F$-FDG의 감마선 에너지 대한 apron 0.25, 0.5 mmPb에 대한 차폐율을 측정하였다. X선 에너지는 관전압 $40{\sim}120\;kVp$ 범위 내에서 부가여과판 0, 2 mmAl을 사용 한 경우에 실효에너지가 $26.2{\sim}45.6\;keV$로 측정되었으며, 이때 apron 0.5 mmPb은 0.25 mmPb보다 최대 선질에서 5.5% 정도 차폐율이 증가하였다. 또한 두 종류의 apron은 직접선과 공간선량률에 대하여 90% 이상의 높은 차폐율을 나타내었다. 그리고 $^{99m}Tc$-MDP의 140 keV에서 0.25, 0.5 mmPb apron을 사용할 경우 $30{\sim}53%$ 정도의 차폐효과가 있었으며, $^{18}F$-FDG의 511 keV의 높은 에너지에서는 $1.3{\sim}3.6%$로 apron의 차폐효과가 매우 적었다.

• Nuclear Engineering and Technology
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• 제53권6호
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• pp.2025-2037
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• 2021

The influence of lead cations on natural quartz (QZ) from Egypt as a glass shielding material for the composition with nominal formula (10Na₂O - (90 - x) QZ - xPbO (where x = 30, 35, 40, 45 and 50 mol %)) was examined. The studied samples are synthesized via the melt quenching method at 1050 ℃. The X-ray diffraction XRD patterns were confirmed the glass nature for studied samples. Moreover, the optical properties, and the transparency for all compositions were examined by UV-Vis spectroscopy. Also, the major elemental composition of the natural quartz were estimated via the X-ray fluorescence (XRF) technique. Further, the density and molar volume were determined. Furthermore, the nuclear shielding parameters such as, mass attenuation coefficient, effective atomic number, electronic density, the total atomic, and electronic cross sections as well as the mean free path, and the half value layer with different gamma ray energies (81 keV-1407 keV) were calculated. Besides, the results showed that the shielding behavior towards the gamma ray radiation for all glass samples was increased as the increment in PbO concentration in the glass system.

• Nuclear Engineering and Technology
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• 제54권3호
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• pp.1049-1061
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• 2022

Neutron and gamma-ray shielding properties of Inconel 718 reinforced B₄C (0-25 wt%) were investigated using PSD software. Mean free path (MFP), linear and mass attenuation coefficients (LAC,MAC), tenth-value and half-value layers (TVL,HVL), effective atomic number (Z_eff), exposure buildup factors (EBF), and fast neutron removal cross-sections (FNRC) values were calculated for 0.015-15 MeV. It was found that MAC and LAC increased with the decrease in the content of B₄C compound by weight in Inconel 718. The EBFs were computed using G-P fitting method for 0.015-15 MeV up to the penetration depth of 40 mfp. HVL, TVL, and FNRC values were found to range between 0.018 cm and 3.6 cm, between 2.46 cm and 12.087 cm, and between 0.159 cm^-1 and 0.194 cm^-1, respectively. While Inconel 718 provides the maximum photon shielding property since it offered the highest values of MAC and Z_eff and the lowest value of HVL, Inconel 718 with B₄C(25 wt%) was observed to provide the best shielding material for neutron since it offered the highest FNRC value. The study is original in terms of several aspects; moreover, the results of the study may be used in nuclear technology, as well as other technologies including nano and space technologies.

• Journal of Radiation Protection and Research
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• 제4권1호
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• pp.14-20
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• 1979

고(高)에너지 방사선(放射線) 치료(治療)에 있어서 정상조직(正常組織)의 완전차폐(完全遮蔽)를 위하여 $5{\sim}8cm$ 납두께의 부정형(不定形) 차폐(遮蔽)벽돌을 제작(製作)해야하는 난점(難點)이 있었다. 저자(著者)들은 납 30.0%, 주석 11.5% 비스므스 48.5%, 카드미늄 10.0%를 사중(四重) 공정결합(共晶結合)시켜 밀도(密度)가 $9.8g/cm^3$ 용융온도(熔融溫度)가 $68^{\circ}C$인 저용융(低熔融) 차폐물질(遮蔽物質)을 개발(開發)하여 이를 Lead Y라고 명명(名命)하였다. 제작(製作)된 Lead Y Block을 $68^{\circ}C$에서 용융(熔融)시켜 보호(保護)해야할 중요(重要)한 장기(臟器)의 형태(形態)대로 제작(製作)된 styrofoam 음형(陰形)에 부어서 차폐효과(遮蔽效果)가 큰 차폐(遮蔽)벽돌을 쉽고 안전(安全)하게 제작(製作)할 수 있었고 납보다 더 단단하고 재현성(再現性)이 크며 저렴(低廉)한 가격(價格)으로 구입(購入)이 가능(可能)하므로 방사선(放射線) 치료효과(治療效果)에 큰 도움을 줄 수 있었다.

• Nuclear Engineering and Technology
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• 제54권9호
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• pp.3470-3477
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• 2022

Soils are porous materials with high shielding capability to attenuate gamma and X-rays. The disposal of radionuclides throughout the soil profile can expose the living organisms to ionizing radiation. Thus, studies aiming to analyze the shielding properties of the soils are of particular interest for radiation shielding. Investigations on evaluating the shielding capabilities of highly weathered soils are still scarce, meaning that additional research is necessary to check their efficiency to attenuate radiation. In this study, the radiation shielding properties of contrasting soils were evaluated. The radiation interaction parameters assessed were attenuation coefficients, mean free path, and half- and tenth-value layers. At low photon energies, the photoelectric absorption contribution to the attenuation coefficient predominated, while at intermediate and high photon energies, the incoherent scattering and pair production were the dominant effects. Soils with the highest densities presented the best shielding properties, regardless of their chemical compositions. Increases in the attenuation coefficient and decreases in shielding parameters of the soils were associated with increases in clay, Fe₂O₃, Al₂O₃, and TiO₂ amounts. In addition, this paper provides a comprehensive description of the shielding properties of weathered soils showing the importance of their granulometric fractions and oxides to the attenuation of the radiation.