• Title/Summary/Keyword: nuclear physics

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Assessment of Internal Dose by $^3H\;&\;^{14}C$ of Total Diet for Inhabitants near Wolsung Nuclear Power Plants

  • Park, G.;Lin, X.J.;Kim, W.;Kang, H.D.;Doh, S.H.;Kim, D.S.;Kim, C.K.
    • Journal of Radiation Protection and Research
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    • v.28 no.1
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    • pp.51-57
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    • 2003
  • To assess the internal dose by $^3H\;&\;^{14}C$ in total diet of inhabitants near Wolsung Nuclear Power Plants, TFWT, OBT and $^{14}C$ concentration in total diet was analyzed for collection region and time. TFWT, OBT and $^{14}C$ concentrations were in the range of 3.19-42.2 Bq/L, 1.00-39.4 Bq/L, and 0.230-0.855 Bq/gC, respectively. The calculated annual effective dose with TFWT, OBT and $^{14}C$ is $6.10{\times}10^{-5}mSv/y,\;3.71{\times}10^{-5}mSv/y\;and\;7.08{\times}10^{-3}mSv/y$, respectively. And then annual internal dose with total diet for inhabitants near Wolsung NPPs is about $7.18{\times}10^{-3}mSv/y$, which is about 0.72% of annual effective dose limit 1 mSv/y.

Implementation and benchmarking of the local weight window generation function for OpenMC

  • Hu, Yuan;Yan, Sha;Qiu, Yuefeng
    • Nuclear Engineering and Technology
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    • v.54 no.10
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    • pp.3803-3810
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    • 2022
  • OpenMC is a community-driven open-source Monte Carlo neutron and photon transport simulation code. The Weight Window Mesh (WWM) function and an automatic Global Variance Reduction (GVR) method was recently developed and implemented in a developmental branch of OpenMC. This WWM function and GVR method broaden OpenMC's usage in general purposes deep penetration shielding calculations. However, the Local Variance Reduction (LVR) method, which suits the source-detector problem, is still missing in OpenMC. In this work, the Weight Window Generator (WWG) function has been developed and benchmarked for the same branch. This WWG function allows OpenMC to generate the WWM for the source-detector problem on its own. Single-material cases with varying shielding and sources were used to benchmark the WWG function and investigate how to set up the particle histories utilized in WWG-run and WWM-run. Results show that there is a maximum improvement of WWM generated by WWG. Based on the above results, instructions on determining the particle histories utilized in WWG-run and WWM-run for optimal computation efficiency are given and tested with a few multi-material cases. These benchmarks demonstrate the ability of the OpenMC WWG function and the above instructions for the source-detector problem. This developmental branch will be released and merged into the main distribution in the future.

Implementation of waste silicate glass into composition of ordinary cement for radiation shielding applications

  • Eid, Mohanad S.;Bondouk, I.I.;Saleh, Hosam M.;Omar, Khaled M.;Sayyed, M.I.;El-Khatib, Ahmed M.;Elsafi, Mohamed
    • Nuclear Engineering and Technology
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    • v.54 no.4
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    • pp.1456-1463
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    • 2022
  • The aim of this work is to study the radiation shielding properties of cement samples with waste glass incortated into its composition. The mass attenuation coefficient (MAC) of the samples were experimentally determined to evaluate their radiation shielding ability. The experimental coefficient was evaluated using NaI detector for gamma energies between 59.53 keV and 1408.01 keV using different radioactive point sources Am-241, Eu-152, Co-60, and Cs-137, and the gamma transmission parameters half-value layer, mean free path, and transmission factor were calculated. The theoretical coefficient of the composites was determined using Geant4 and XCOM software. The results were also compared against Geant4 and XCOM simulations by calculating the relative deviation between the values to determine the accuracy of the results. In addition the mechanical properties (including Compressive and porosity) as well as the thermogravimetric analysis were tested for the present samples. Overall, it was concluded that the cement sample with 50% waste glass has the greatest shielding potential for radiation shielding applications and is a useful way to reuse waste glass.

Conceptual design of hybrid target for molybdenum-99 production based on heavywater

  • Ali Torkamani ;Ali Taghibi Khotbehsara ;Faezeh Rahmani ;Alexander Khelvas ;Alexander Bugaev ;Farshad Ghasemi
    • Nuclear Engineering and Technology
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    • v.55 no.5
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    • pp.1863-1870
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    • 2023
  • Molybdenum-99 (99Mo) is used for preparing Technetium-99 m (99mTc), which is the most widely used isotope in nuclear medicine. In this work, a study for 99Mo production based on a high-power electron accelerator has been performed as an alternative approach to produce 99mTc. In this study, Monte Carlo MCNPX2.6 code has been used to examine a novel idea of simultaneous hybrid production of 99Mo via both photoneutron and neutron capture reactions using an electron accelerator in heavy water tank. It is expected that this conceptual design including an arrangement of metallic plates of 100Mo and 98Mo produces total activity of 97.5 Ci at the end of 20-h continuous e-beam irradiation (30 MeV, 10 mA).

Neutronics analysis of the ion cyclotron resonance heating antenna of the China Fusion Engineering Test Reactor

  • Gaoxiang Wang;Chengming Qin;Shanliang Zheng;Yongsheng Wang;Kun Xu;Huiqiang Ma
    • Nuclear Engineering and Technology
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    • v.56 no.8
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    • pp.3236-3241
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    • 2024
  • Ion cyclotron resonance heating (ICRH) is an important auxiliary heating method applied to the China Fusion Engineering Test Reactor, which can effectively heat the ions and electrons in plasma. Owing to the harsh nuclear environment, neutronic analyses are required to verify tritium self-sufficiency and neutron-shielding requirements. In this study, a neutronics analysis of the ICRH antenna was conducted using the COre and System integrated engine for Reactor Monte Carlo (cosRMC) code to estimate the neutron flux, radiation damage, nuclear heating, gas generation rate of key components, and tritium breeding ratio (TBR), providing data support for the subsequent optimization of the shielding design. In addition, the neutron flux of the coils around the antenna was calculated to prevent the entry of neutrons that damage the magnetic field coils through the gaps between the port plugs and antenna, and the shielding effects of the port-plug antenna on the surrounding components were analyzed. Finally, the results obtained using the cosRMC and MCNP codes were compared, which and presented good agreement, thus verifying the reliability of the neutronic analysis using the cosRMC code.

An adaptive deviation-resistant neutron spectrum unfolding method based on transfer learning

  • Cao, Chenglong;Gan, Quan;Song, Jing;Yang, Qi;Hu, Liqin;Wang, Fang;Zhou, Tao
    • Nuclear Engineering and Technology
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    • v.52 no.11
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    • pp.2452-2459
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    • 2020
  • Neutron spectrum is essential to the safe operation of reactors. Traditional online neutron spectrum measurement methods still have room to improve accuracy for the application cases of wide energy range. From the application of artificial neural network (ANN) algorithm in spectrum unfolding, its accuracy is difficult to be improved for lacking of enough effective training data. In this paper, an adaptive deviation-resistant neutron spectrum unfolding method based on transfer learning was developed. The model of ANN was trained with thousands of neutron spectra generated with Monte Carlo transport calculation to construct a coarse-grained unfolded spectrum. In order to improve the accuracy of the unfolded spectrum, results of the previous ANN model combined with some specific eigenvalues of the current system were put into the dataset for training the deeper ANN model, and fine-grained unfolded spectrum could be achieved through the deeper ANN model. The method could realize accurate spectrum unfolding while maintaining universality, combined with detectors covering wide energy range, it could improve the accuracy of spectrum measurement methods for wide energy range. This method was verified with a fast neutron reactor BN-600. The mean square error (MSE), average relative deviation (ARD) and spectrum quality (Qs) were selected to evaluate the final results and they all demonstrated that the developed method was much more precise than traditional spectrum unfolding methods.

CHARACTERISTICS OF SELF-LEVELING BEHAVIOR OF DEBRIS BEDS IN A SERIES OF EXPERIMENTS

  • Cheng, Songbai;Yamano, Hidemasa;Suzuki, TYohru;Tobita, Yoshiharu;Nakamura, Yuya;Zhang, Bin;Matsumoto, Tatsuya;Morita, Koji
    • Nuclear Engineering and Technology
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    • v.45 no.3
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    • pp.323-334
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    • 2013
  • During a hypothetical core-disruptive accident (CDA) in a sodium-cooled fast reactor (SFR), degraded core materials can form roughly conically-shaped debris beds over the core-support structure and/or in the lower inlet plenum of the reactor vessel from rapid quenching and fragmentation of the core material pool. However, coolant boiling may ultimately lead to leveling of the debris bed, which is crucial to the relocation of the molten core and heat-removal capability of the debris bed. To clarify the mechanisms underlying this self-leveling behavior, a large number of experiments were performed within a variety of conditions in recent years, under the constructive collaboration between the Japan Atomic Energy Agency (JAEA) and Kyushu University (Japan). The present contribution synthesizes and gives detailed comparative analyses of those experiments. Effects of various experimental parameters that may have potential influence on the leveling process, such as boiling mode, particle size, particle density, particle shape, bubbling rate, water depth and column geometry, were investigated, thus giving a large palette of favorable data for the better understanding of CDAs, and improved verifications of computer models developed in advanced fast reactor safety analysis codes.

A modified analytical model of proton Bragg curves

  • Takizawa, Ken-ichi;Yoshihisa Takada;Takeharu Nakashima;Syunsuke Kohno;Yuhsuke Kobayashi
    • Proceedings of the Korean Society of Medical Physics Conference
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    • 2002.09a
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    • pp.186-188
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    • 2002
  • An improved analytical model has been developed to calculate an accurate Bragg curve of proton beam with an arbitrary energy. The model takes the transport of the secondary protons produced by the nuclear inelastic reactions into account. By the model, measured Bragg curves of proton beams with ten energies between 250 and 70 MeV are reproduced well. It will serve to obtain fundamental data for treatment planning and for energy scanning.

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The design and fabrication of 81.25 MHz RFQ for Low Energy Accelerator Facility

  • Zhao, Bo;Chen, Shuping;Zhu, Tieming;Wang, Fengfeng;Jin, Xiaofeng;Li, Chenxing;Ma, Wei;Zhang, Bin
    • Nuclear Engineering and Technology
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    • v.51 no.2
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    • pp.556-560
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    • 2019
  • To provide high shunt impendence with low power losses, an 81.25 MHz continuous wave (CW) radio frequency quadrupole (RFQ) accelerator has been designed and machined as parts of the Low Energy Accelerator Facility (LEAF). In this paper, the mechanical structure and the main processing technology of the RFQ cavities are described according to the physical and geometric parameters requirements of the RFQ. The fabrication of the RFQ has been completed and the test results agree well with the design requirements. The RFQ accelerator will work in Institute of Modern Physics, Chinese Academy of Sciences in 2018.

An investigation of the nuclear shielding effectiveness of some transparent glasses manufactured from natural quartz doped lead cations

  • Kassem, Said M.;Ahmed, G.S.M.;Rashad, A.M.;Salem, S.M.;Ebraheem, S.;Mostafa, A.G.
    • Nuclear Engineering and Technology
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    • v.53 no.6
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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.