中性子束 Neutron Flux
百科事典、科学ニュース、研究レビュー
序章
中性子束 φ は、原子核および原子炉の物理学で使用されるスカラー量です。これは、単位時間および単位体積あたりにすべての自由中性子が移動する合計距離です。同様に、小さな半径の球を通過する中性子の数として定義できます。 R. {\displaystyle R} 時間間隔で割った値 円周率 R. 2 {\displaystyle \piR^{2}} （球の断面積）と時間間隔。 : 82-83 通常の単位は cm−2s−1 (中性子の数/平方センチメートル/秒) です。 中性子フルエンスは、一定期間にわたって積分された中性子束として定義されるため、通常の単位は cm−2 (平方センチメートルあたりの中性子数) です。 cm−2 の代わりに使用されていた古い用語は n.v.t でした。 (中性子、速度、時間)。
学術論文
...This article aims to investigate the computational distribution of neutron flux using Maxwell-Boltzmann statistics.....
...The optimized angular-distribution-corrected fast-neutron flux-weighted partial γ -ray cross section for the production of the 846.....
...The reactor power is proportional to the neutron flux in the reactor core, and the reactor period is the time that the reactor power changes by a factor of 2.....
...It is because the neutron flux in underground laboratories is usually very low and it is easy to<br>make a mistake in interpreting of the results.....
...The main neutronic characteristics, including the neutron spectrum, reactivity control with control drums inserted in the radial reflector, temperature reactivity coefficient (TRC), neutron flux, power deposition, and neutron balance are provided and discussed, respectively.....
...Yet, this methodology has only been applied when the material activation is due to the interaction with a neutron flux.....
...The core configuration of the TRIGA MARK I IPR-R1 nuclear research reactor, Brazil, has been modified six times since the first criticality and the neutron fluxes have been determined using experimental and semi theoretical methodologies determining the neutron fluxes in different irradiation channels and devices, applying different procedures and materials.....
...IFMIF-DONES aims at providing high-energy deuterons to produce a neutron flux to test materials.....
...Operational defects are primarily diagnosed by detectors that capture changes in the neutron flux, placed at various points inside and outside of the core.....
...The neutronic safety parameters are keff, neutron flux, core excess reactivity, shutdown margin, control rod total reactivity value, and PPF.....
...Previous works by the authors have introduced the spatial flux variation method (SFV) for predicting the changes in neutron flux due to a change in material compositions.....
...Having a physical model of particle interactions based on the Geant4 package, it is possible to calculate the detection efficiency for various types of detectors, which are used in experiments conducted at the Tien Shan high-mountain station related to the registration of a neutron flux.....
...According to neutron diffusion phenomena, this modeling method has a better physical interpretation for a quick change of neutron flux in load-following operation mode.....
...The characterization of the East Radiography Station involved experiments used to measure the following characteristics: Neutron flux, neutron beam uniformity, cadmium ratio, image quality, and the neutron energy spectrum.....
...This method uses precise estimation of the neutron flux at different altitudes of spacecraft orbits modelled with specially developed code based on the Geant4 toolkit with additional treatment of the neutron propagation in the lunar gravity field.....
...The one-speed neutron diffusion equation is solved analytically for various homogeneous nonmultiplying and multiplying media in different geometries and the shape of neutron flux is discussed.....
...The excess reactivity, neutron flux and power density distributions and power peaking factor are also examined.....
...The neutron flux of compact neutron sources is low, making it difficult to measure scattered neutrons with a typical small-angle neutron scattering (SANS) geometry.....
...By introducing a large scale high-fidelity unstructured meshes, high fidelity distributions of power and neutron flux were gained and compared with the results from other codes, excellent consistency were observed.....
...We present results of the photocurrent in LYSO+SiPM packages induced by Co-<inline-formula> <tex-math notation="LaTeX">$60~\gamma $ </tex-math></inline-formula>-rays and Cf-252 neutrons of the expected dose rate and neutron flux, respectively.....
...The variation of neutron fluxes with respect to radial distance for the best CC and the fresh core was illustrated.....
...Recently developed Samarium Cobalt rare earth magnets were utilized that have demonstrated resilience to temperature and neutron flux up to 550 °C and 1018 n/cm2, respectively.....
...In this study, the dynamic characteristics of accelerator-driven subcritical reactor (ADSR) under beam transients with high heterogeneity of neutron flux in time-space are investigated.....
...The questions of optimizing the configuration of the core and the regime of reactors operation for increasing the neutron flux in the irradiation channels are discussed.....
...The simulation is based on predictions of neutron flux and neutronics together with signal and background generation.....
...This chapter introduces some basic elements of the neutron transport equation, such as the concept of neutron flux, cross sections, current, reaction rate, etc.....
...An estimate of the neutron flux on the sample is obtained.....
...Due to the use of JFET transistors, the proposed CMs operate in the low temperature range (up to -197°C), as well as with a neutron flux up to 1014n/cm2.....
...In the BWR system designed in the study; keff, neutron flux, fission energy, heating, and depleted Am were calculated.....
...by the measurement of neutron flux.....
...Some experiment data of Molten Salt Reactor Experiment (MSRE) are chosen to verify the code, and the core characteristics including the distributions of neutron fluxes, DNP and temperature under the rated condition are simulated and discussed.....
...The PWR ThO2-UO2 fuel in the cladding with the fuel assembly model 17 x 17 is analyzed by its fuel burn up, neutron flux and isotope composition after maximum operation.....
...Throughout its operating cycle, the facility is subcritical and is controlled using the neutron flux from the plasma source.....
自然中性子束
漸近巨大枝星や超新星の中性子束は、鉄より重い元素を生成する自然の元素合成のほとんどを担っています。星の中性子束は 105 ～ 1011 cm-2s-1 程度と比較的低く、その結果、s プロセス (低速中性子捕捉プロセス) を介して元素合成が行われます。対照的に、核崩壊超新星の後では、1032 cm-2s-1 程度の非常に高い中性子束が発生し、r プロセス (急速中性子捕捉プロセス) を介して元素合成が起こります。 地球の大気中性子束は、明らかに雷雨によるもので、3・10−2 から 9・10+1 cm−2 s−1 のレベルに達することがあります。しかし、遮蔽されていないシンチレーション中性子検出器で得られた最近の結果（最初の研究者らは無効であると考えていた）では、雷雨の間の中性子束が減少することが示されています。最近の研究では、雷が光核過程を介して放電ごとに 1013 ～ 1015 個の中性子を生成することが確認されているようです。
人工中性子束
人工中性子束とは、兵器や核エネルギー生産の副産物として、または研究炉や核破砕などの特定の用途のために人工的に作成された中性子束を指します。中性子束は、大きくて不安定な原子核の核分裂を開始するためによく使用されます。追加の中性子は原子核を不安定にし、原子核を崩壊（分裂）させてより安定した生成物を形成する可能性があります。この効果は、核分裂炉や核兵器では不可欠です。 核分裂炉では、中性子束は内部反応を制御するために測定される主要な量です。磁束形状は、リアクターの周りを移動する磁束の密度または相対的な強度に適用される用語です。通常、最も強い中性子束は炉心の中心で発生し、端に向かうにつれて減少します。中性子束が高くなるほど、単位時間当たりにその領域を通過する中性子が多くなり、核反応が起こりやすくなります。
= 原子炉容器壁の中性子フルエンス =
典型的な原子力発電所 (PWR) の原子炉容器は、運転期間 40 年間 (すべての原子炉では 32 年間)、約 6.5 × 1019 cm-2 (E > 1 MeV) の中性子フルエンスに耐えます。中性子束により原子炉容器が中性子脆化します。
こちらも参照
中性子線 中性子輸送
ホウ素中性子捕獲
学術論文
...An accelerator-based boron neutron capture therapy (BNCT) system employing a solid-state Li target can achieve sufficient neutron flux for treatment although the neutron flux is reduced over the lifetime of its target.....
...The neutron source is capable of producing the high neutron flux for boron neutron capture therapy (BNCT).....
...The present work is aimed to measure neutron fluxes and gamma fluxes around the Boron Neutron Capture Therapy (BNCT) research facility at the PUSPATI TRIGA Reactor.....
...The neutron source is capable of producing the high neutron flux in various energy ranges, from thermal to fast, for boron neutron capture therapy, as well as for other applications.....
...The proposal is staged with the first stage offering a medium neutron flux, linear accelerator-based approach for neutron scattering that is also coupled with a boron neutron capture therapy (BNCT) station and a positron emission tomography (PET) isotope production station.....
...However, the optimization on the thermal neutron flux produced should be performed to gain a sufficient thermal neutron for boron neutron capture therapy purpose.....
熱中性子束
学術論文
...A thermal neutron flux measurement tool with two perpendicular sets of plastic scintillator arrays was designed and simulated (Ghal-Eh and Green, 2016) with the MCNPX code (Version 2.....
...Since the thermal neutron flux available for NR using above sources (in an enclosure based set up) is very low (104 n/cm2 s), the quality of the neutron images is less in comparison to NR images obtained from setups that use nuclear reactor as neutron source (107 n/cm2 s).....
...The effect of adding 1 wt % of MAs to the main three fuel types on the infinity multiplication factor (Kinf), thermal neutron flux and the actinides’ concentration is investigated using MCNPX code version 2.....
...The improved system provides thermal neutron flux of 3.....
...The geometrical arrangement of the unit has been simulated with primary goal to provide the highest thermal neutron flux in the location of the examined item.....
...By using neutronics computer code as MCNP6, the obtained calculation results of I-131 activity in 6 investigated cases showed that the new design by the re-arrangement of the neutron trap can be used effectively for radioisotope production with thermal neutron flux in average range from 5.....
..., to maximize the keff or maximum thermal neutron flux while maintaining low power peaking factor.....
...This work demonstrates an approach to determine probability of perturbation of the axial profile of the thermal neutron flux in the Advanced Test Reactor.....
...Simulation results show that the normalized thermal neutron flux of 1.....
...As a tie rod material in a high thermal neutron flux environment, Inconel X-750 is more likely to be IASCC sensitive during service in a BWR due to helium than the XM-19 stainless steel alloy because of a greater nickel content and boron concentration.....
...Semiconductor thermal neutron detectors are increasingly been used in in-core thermal neutron flux measurements in nuclear reactors.....
...The results demonstrate that the proposed system, using a pair of boron-enriched and boron-free scintillators, could be successfully used for monitoring of thermal neutron flux and estimation of irradiation dose.....
...In this work, MC21 is used to simulate the decay of the equilibrium thermal neutron flux in light-water spheres of several radii.....
...5% at the 1σ level at the positions with high thermal neutron fluxes where the errors were dominantly introduced by uncertainties in the monitoring of the neutron production rate.....
...This last characteristic has ensured that this detector is one of the best tools for thermal neutron flux measurements in a nuclear reactor control.....
...The internal structure of several alkali-borosilicate glasses has been studied when exposed to a high thermal neutron flux.....
...The Samples and standards were irradiated for 6 h at “NUR” research reactor with a thermal neutron flux of 1013 n cm−2 s−1, and analyzed by gamma ray spectrometry using HPGe detector.....
...Compared with the original neutron beam, the shifter increased the thermal neutron flux at the skin by approximately 4 times.....
...Then, the pinhole imaging detector (pinhole) of MCNP has been used to simulate the imaging process of the coded neutron source imaging, and the parameters such as the uniformity of the spatial distribution of the thermal neutron flux at the imaging plane and the uniformity of the angular emission of the coded neutron source are studied.....
...Lithium ceramics samples were irradiated at the WWR-K research reactor (Almaty, Kazakhstan) under continuous pumping conditions at a temperature of ~610°C for ~21 days with a thermal neutron flux of ~5•1013 n/(cm2•s).....
...The key variable analyzed is the thermal neutron flux in the irradiation devices.....
...In this study, compacting TRR core configuration, as a method to increase thermal neutron flux in the central in-core irradiation position to provide desired neutronic environment for fuel irradiation tests, is of concern.....
...The moderated thermal neutron fluxes at different distances from an Am-Be neutron source, calibrated by the activation foil method, were investigated using the compensation system.....
...Firstly, the infinity multiplication factor (Kinf), thermal neutron flux, and power distribution have been studied for the investigated fuel types.....
...With Monte Carlo software GEANT4, the SERS-based thermal neutron detector has been proven to have almost no effect on original thermal neutron flux as well as the distribution and could be used for thermal neutron detection accurately.....
...Besides, the sensor has a neutron to gamma-ray rejection ratio of 1568 at a thermal neutron flux rate of 135.....
...The goal of optimal design is to maximize the thermal neutron flux at the output surface and improve the utilization efficiency of the neutron generator.....
...These parameters include the approach to critical, primary coolant void coefficient of reactivity, flux trap void coefficient of reactivity, determination of flux trap sample reactivity worth, radial and axial thermal neutron flux mapping, control blade worth calibration, primary and pool coolant temperature coefficient of reactivity, and flux mapping of experimental positions.....
...The maximum thermal neutron flux density outside the reactor biological shield was 1.....
...The neutron irradiation is performed in the BR2 reactor with mixed neutron spectrum up to 1 dpa (end of life fluence for ITER) but with appropriate measures to reduce the thermal neutron flux, such that the spurious transmutation into rhenium is reduced.....
...However, the optimization on the thermal neutron flux produced should be performed to gain a sufficient thermal neutron for boron neutron capture therapy purpose.....
...This investigation described the development of a method for the reactor production of no-carrier-added (NCA) 199Au through neutron activation of natural Pt in Tehran Research Reactor (TRR) at a thermal neutron flux of 3.....
...The thermal neutrons were indirectly identified by the characteristic (478 keV) γ -rays from the 10 B ( n , α ) reactions and the corresponding thermal neutron fluxes were extracted by fitting the energy spectrum measured by the boron-loaded plastic scintillator in this work.....
...For the aspect of confirmatory experiments, we emphasize on the methods and instruments, including the control rods (CRs) critical position, the CR worth curve, and the thermal neutron flux distribution.....
高中性子束
学術論文
...The neutron source is capable of producing the high neutron flux for boron neutron capture therapy (BNCT).....
...The China Spallation Neutron Source (CSNS) operates in pulsed mode and has a high neutron flux.....
...At facilities with sufficiently high neutron flux (>1 × 106 n/cm2/sec), the basic design does not necessitate amplification of scintillation photons prior to their registration by the CCD camera.....
...The neutron source is capable of producing the high neutron flux in various energy ranges, from thermal to fast, for boron neutron capture therapy, as well as for other applications.....
...This paper reports the test performed on a 3 layers converter prototype coupled to a GEMPix detector (Murtas in Radiat Meas 138:106421, 2020), carried out in order to study the possibility to produce a large-scale multi-layer neutron detector capable to reach high detection efficiency with high spatial resolution and able to sustain the high neutron flux expected in the new neutron spallation source under development like the ESS.....
...The PPF relates the maximum local linear power density to the average power density in a fuel rod indicating a high neutron flux that can cause fuel rod damage.....
...The combination of high neutron flux on a sample, wide-aperture multidetector systems, and focusing devices has made it possible to implement diffraction experiments on samples with record-low volumes under ultrahigh pressures (up to 35 GPa) in the temperature range of 5–300 K.....
...The low efficiency of the detector enables it to be used at high neutron fluxes.....
高速中性子束
学術論文
...The degradation of concrete induced by neutron radiation and elevated temperature can lead to considerable increases of thermal and fast neutron flux/fluence in the concrete.....
...Similarly, the measured fast neutron flux increased by about 22%.....
...The applications of GRCM in the diagnostics of neutrinos, neutrons, charged particles, thermonuclear plasma thermometry, and the study of the structure and dynamics of astrophysical objects, position-sensitive dosimetry of neutron targets with accelerator driving, spatial distribution of the fast neutron flux density in a nuclear reactor allowing the transformation of longitudinal coordinate of neutron flux distribution into a temporal distribution of the radiochemical gas decay counting rate (“barcode” semblance) and measurement of bombarding particles spectra are described.....
...The requirements of the PGAA facility include a very high thermal to fast neutron flux ratio and a focused, thin beam.....
...The nuclear analyses are carried out by the Monte Carlo N-particle (MCNP) transport code, including the TBR, neutron wall loading (NWL), fast neutron flux on inboard side, and nuclear heating deposition on main in-vessel components.....
...The applied fast neutron flux is representative of ITER irradiation conditions in terms of damage rate.....
...It is often used to test the ability of the advanced transport calculation method of calculating RPV fast neutron flux and to evaluate the accuracy of cross-section library.....
測定された中性子束
学術論文
...These inaccuracies cause deviations between the predicted and measured neutron flux distribution, which can be reduced with an adaptation of the neutronic model to the measurements.....
...This experiment measured neutron flux and decay rate simultaneously with a time projection chamber using a pulsed neutron beam.....
...When measuring the fundamental mode decay constant γ in an exponential experiment, it is difficult to extract the fundamental mode from a measured neutron flux distribution that is contaminated by many higher harmonics.....
最大中性子束
学術論文
...313 × 109 Bq, the maximum neutron flux emitted from the Be layer was 4.....
...It was observed that the higher advection gradient, the lower the maximum neutron flux occurring in the nuclear core, a result which is practical for different reactors shapes.....
...To generate maximum neutron flux, prevent overheating of the target and reduce thermal stress during the facility power operation one should provide uniform electron beam distribution at the target top surface.....
全中性子束
学術論文
...The MCNP6 calculated total neutron flux was compared with that from the Serpent simulation.....
...Three experimental data sets are used to test the algorithm: (1) an optical fiber heated to >950°C, (2) an aluminum-embedded optical fiber under strain from differential thermal expansion, and (3) an optical fiber exposed to a total neutron flux of $2\times 10^{13}$ n/cm2/s over 40 hours in a nuclear test reactor.....
...Three physical quantities are evaluated: neutron flux spectra and total neutron fluxes on target's z-axis, and the neutron yield as a function of the target's altitude and radius.....
熱外中性子束
学術論文
...This facility will be built to provide neutrons with energies resembling the Watt fission neutron spectrum by reducing thermal and epithermal neutron flux.....
...In this work, an activation detector using 55Mn(n,γ)56Mn reaction is designed by Monte Carlo simulations to measure the epithermal neutron flux of BNCT treatment beam.....
...s epithermal neutron flux with acceptable beam contaminations.....
エネルギー中性子束
学術論文
...Extreme operational environment, such as high-energy neutron flux, electromagnetic radiation, and high temperatures might reduce the performance of the detector systems.....
...The 93mNb samples were irradiated using continuous energy neutron flux.....
...It was established that combinations of these parameters, which provide the possibility of inverting the population of the excitation levels of Gd-156 isotope nuclei were largely determined by the energy neutron flux spectrum in pulses.....
中性子線束
学術論文
...The tritium values are correlated with the cosmic ray neutron flux data at ground level, available for Greece in the same period.....
...The proposed formula has the unique feature of decoupling between failure cross section and cosmic ray neutron flux.....
入ってくる中性子束
学術論文
..., absolute humidity, air pressure, incoming neutron flux intensity) were evaluated to determine their impacts on the neutron counts in the Seolmacheon experimental site (SMC) located in mountainous terrain.....
...Raw fast neutron counts were corrected for atmospheric pressure, atmospheric water vapor, and incoming neutron flux.....
中性子束の測定
学術論文
...Experimental results indicate that this neutron detector can measure neutron flux up to 1 × 109 (cm-2 s-1), separately from gamma rays around 500 mGy/h.....
...The present work is aimed to measure neutron fluxes and gamma fluxes around the Boron Neutron Capture Therapy (BNCT) research facility at the PUSPATI TRIGA Reactor.....
中性子束を計算する
学術論文
...Generally, the thermal hydraulic (TH) codes need the results of Neutron Kinetics (NK) codes providing the reactivity properties to calculate neutron flux.....
...This hybrid scheme uses a fission source calculated by a deterministic code in order to precisely calculate neutron fluxes in the shielding with a Monte-Carlo code using variance reduction techniques.....
コア中性子束
学術論文
...The analog-based Ex-core Neutron Flux Monitoring System (ENFMS) in Korean Nuclear Power Plants (NPPs) has been performing its intended functions successfully for a long time.....
...An ex-core neutron flux measurement is a crucial system for all common power reactors.....
レベル中性子束
学術論文
...The critical boron concentration and a set of pin-level neutron flux profiles are compared against measurements, with very good agreement.....
...A good agreement is found comparing the critical boron concentration and a set of pin-level neutron flux profiles against measurements.....
状態中性子束
学術論文
...The general noise equations are obtained by assuming small perturbations around a steady-state neutron flux and by subsequently taking the Fourier transform in the frequency domain.....
...HFIR provides one of the highest steady-state neutron fluxes of any research reactor in the world to support scientific missions including cold and thermal neutron scattering, isotope production, and materials irradiation research.....
コリメートされた中性子束
学術論文
...A conceptual design and performance studies for a collimated neutron flux monitor and neutron spectrometer for the Divertor Tokamak Test (DTT) facility are presented.....
...In order to assist the magnetic diagnostics and at the same time provide a novel tool to benchmark them, here the measurement of the plasma magnetic axis position by means of a collimated neutron flux monitor is proposed.....
Adjoint Neutron Flux
学術論文
...The generalized perturbation method is described relevant to ratios of bi-linear functionals of the real and adjoint neutron fluxes of critical multiplying systems.....
...The forward and adjoint neutron flux distributions that are required for perturbation theory are reconstructed using a combination of core-wide homogeneous-assembly solutions from the VARIANT transport code and the unstructured, heterogeneous single-assembly solutions from the PROTEUS-SN transport code.....
Spectral Neutron Flux
学術論文
...The simulator works with continuous variables of the phase space relevant in transport theory, which allows to extract the simulated spectral neutron flux and render it in parameterized representation.....
...In order to determine the cross sections of the (n,xn) reactions, the spectral neutron flux distribution is needed, thus the characterization of the beam is of major importance.....
スカラー中性子束
学術論文
...The proposed scheme relies on the use of reduced-order transport simulations at the substeps, allowing the new compositions to influence the scalar neutron flux in other materials, approaching a time-continuous model of reaction rates.....
...In order to solve the eigenvalue problem, a modified power method is used to obtain the dominant eigenvalue (effective multiplication factor) and its corresponding eigenfunction (scalar neutron flux), which is non-negative in every domain, that is, physically relevant.....
平均中性子束
学術論文
...In most power level control systems of NPPs, the power level or average neutron flux in reactor cores provided by out-of-core neutron sensors are usually measured as feedback of power control systems, while, as critical measuring devices, there is a risk of damage to out-of-core neutron sensors.....
...The maximum and average neutron fluxes in the core were 4.....
中性子束分布
学術論文
...These inaccuracies cause deviations between the predicted and measured neutron flux distribution, which can be reduced with an adaptation of the neutronic model to the measurements.....
...For the neutron diffusion equation, a reaction-rate within the imprecisely known domain boundaries has been chosen as a representative scalar-valued response, and the neutron flux distribution within the imprecisely known domain boundaries has been chosen as a representative function-valued response.....
...The paper presents the results of the calculation of neutron flux distribution and k effective factor in the ADSR with different reflector materials.....
...In this work, the neutron flux distribution method to determine the effective multiplication coefficient keff has been numerical analysis by MCNP program.....
...Among all the possible occurring reactivity effects of a fast reactor, the situations whereby the control rod was inserted, or the coolant was voided could lead to strong anisotropy of neutron flux distribution, therefore the angular dependence on neutron flux should be considered during the few-group cross-sections generation.....
...Significant improvements were also observed in the AGREE neutron flux distributions compared to the SERPENT full core calculation.....
...The neutron flux distribution in the core region of the JRTR was measured through the neutron activation analysis method.....
...In addition, the OpenMC WWM function has also been applied on the IFMIF-DONES Test Cell global neutron flux distribution calculations.....
...Also, neutron flux distribution, reflector saving, water level effect, and lattice pitch of the core including operating point of the facility are studied in details.....
...These include calculations of neutron flux distributions and Shutdown Dose Rate (SDDR), following SA2 [4] scenario, in a baseline configuration and exploring the option of adding additional shielding plates in the PF.....
...The important thing in the CP method is the CP matrix calculation, better known as has an important role in determining the neutron flux distribution in the reactor core.....
...When measuring the fundamental mode decay constant γ in an exponential experiment, it is difficult to extract the fundamental mode from a measured neutron flux distribution that is contaminated by many higher harmonics.....
...Infinitive multiplication factor kinf, neutron flux distribution and neutron spectra of the fuels were calculated.....
...In performing this work, we utilized both a 3-D Cartesian SN deterministic code, PENTRAN, and a Monte Carlo code, MCNP6, to calculate complimentary, high accuracy 3-D transport derived neutron flux distributions at reactor full power.....
...Moreover, spatial neutron flux distributions using F-mesh card over the bundle and the control blade are investigated at inserting and withdrawing the B4C.....
...The SRA is characterized by calculating the 3-dimensional neutron flux distribution and neutron spectrum.....
...For the aspect of confirmatory experiments, we emphasize on the methods and instruments, including the control rods (CRs) critical position, the CR worth curve, and the thermal neutron flux distribution.....
...The feeding of isomeric state from neutron reaction is more sensitive to the variation of neutron flux distribution than the nucleus formation.....
...In order to determine the cross sections of the (n,xn) reactions, the spectral neutron flux distribution is needed, thus the characterization of the beam is of major importance.....
...The forward and adjoint neutron flux distributions that are required for perturbation theory are reconstructed using a combination of core-wide homogeneous-assembly solutions from the VARIANT transport code and the unstructured, heterogeneous single-assembly solutions from the PROTEUS-SN transport code.....
中性子束密度
学術論文
...A series of calculation studies are performed with a simulation of the core region of the WWR-K reactor using an MCNP transport code including determination of neutron flux density, reactivity, efficiency of the control rods of the control and protection systems, as well as kinetic parameters critical for ensuring safe reactor operation.....
...Analytical dependences of charge carrier mobility and switching delay time on neutron flux density are obtained.....
...The neutron flux density is clarified for different values of the time-fractional order.....
...Experiment results show that under a neutron flux density of 11.....
...Thus, taking into account the energy output, power operation modes, and neutron flux density in the core, over time, nuclides that are not characteristic of the original composition of the concrete component are formed in the nodes of the crystal lattice.....
...The applications of GRCM in the diagnostics of neutrinos, neutrons, charged particles, thermonuclear plasma thermometry, and the study of the structure and dynamics of astrophysical objects, position-sensitive dosimetry of neutron targets with accelerator driving, spatial distribution of the fast neutron flux density in a nuclear reactor allowing the transformation of longitudinal coordinate of neutron flux distribution into a temporal distribution of the radiochemical gas decay counting rate (“barcode” semblance) and measurement of bombarding particles spectra are described.....
...The expanded experimental capabilities of the IVV-3 reactor, which are associated with an increase in the thermal power and neutron flux density in experimental bodies, will make it possible not only to keep the existing research and production base but also to become in-demand for solving new problems of the nuclear industry.....
...A core model is built by MCNP5, and the uniform control rod is replaced by non-uniform control rod of N = 2 and 4 (N is the nonuniformity coefficient of non-uniform control), then the axial neutron flux density distributions at different rod positions are calculated and compared.....
...The maximum thermal neutron flux density outside the reactor biological shield was 1.....
...Therefore, the influence of the nuclear fuel depletion of fuel assemblies in the WWER-1000 reactor on the change of the basic neutron-physical characteristics was determined such as the distribution of the neutron flux density with the energies necessary to initiate the 16O(n,p)16N reaction, the average number of neutrons per fission, the neutron spectrum and average fission energy.....
中性子束測定
学術論文
...A thermal neutron flux measurement tool with two perpendicular sets of plastic scintillator arrays was designed and simulated (Ghal-Eh and Green, 2016) with the MCNPX code (Version 2.....
...Neutron flux measurements in research reactors can be used for code validation and optimizing in-core activation procedures.....
...To minimise uncertainty and strengthen estimation of energy deposited during power transients, we set up an online passive neutron flux measurement of a pulse reactor.....
...Natural radioactivity studies were performed and included in situ gamma spectrometry, neutron flux measurements, radon concentration, and alpha and gamma laboratory spectrometry measurements of rock samples.....
...Semiconductor thermal neutron detectors are increasingly been used in in-core thermal neutron flux measurements in nuclear reactors.....
...This last characteristic has ensured that this detector is one of the best tools for thermal neutron flux measurements in a nuclear reactor control.....
...Neutron flux measurements before and after the upgrade show that the expected instrument-dependent flux gain of a factor 2–10 was achieved.....
...An ex-core neutron flux measurement is a crucial system for all common power reactors.....
...At the formation of the helical RFP, neutron flux measurements indicate a drastic loss of fast ions at sufficient subdominant mode amplitudes.....
中性子束モニター
学術論文
...In this method, a set of three neutron flux monitors were irradiated without Cd-cover.....
...A conceptual design and performance studies for a collimated neutron flux monitor and neutron spectrometer for the Divertor Tokamak Test (DTT) facility are presented.....
...In the large helical device (LHD), beam ion and deuterium–deuterium fusion-born triton transport due to resistive interchange mode destabilized by helically-trapped energetic ions (EIC) are studied employing comprehensive neutron diagnostics, such as the neutron flux monitor and a newly developed scintillating fiber detector characterized by high detection efficiency.....
...In foils were used as a neutron flux monitor based on 115In(n, n′)115mIn reaction.....
...This paper reports the design of a neutron flux monitor (NFM) system based on field-programmable gate array (FPGA) with a temporal resolution of 1 ms, and a faster time response of 0.....
...In order to assist the magnetic diagnostics and at the same time provide a novel tool to benchmark them, here the measurement of the plasma magnetic axis position by means of a collimated neutron flux monitor is proposed.....
...First, in order to confirm that the graphite thermal column was a well-thermalized neutron field, neutron irradiation was performed with neutron flux monitors: 197Au, 59Co, 45Sc, 63Cu, and 98Mo.....
...The absolute calibration of the detection efficiency for the total neutron yield in the whole plasma is one of the most important issues in the neutron diagnostics such as a neutron flux monitor (NFM).....
...The neutron flux monitor (NFM) is one of the most important diagnostic systems for ITER.....
中性子束モニタリング
学術論文
...The analog-based Ex-core Neutron Flux Monitoring System (ENFMS) in Korean Nuclear Power Plants (NPPs) has been performing its intended functions successfully for a long time.....
...We present experimental and MCNP modeled results of neutron flux monitoring in an irradiator, which consists of a252Cf sealed source housed in the center of a cubic block of high-density polyethylene.....
...Neutron flux monitoring in research reactors can range from shutdown to full power over 10 to 12 decades.....
中性子束プロファイル
学術論文
...The critical boron concentration and a set of pin-level neutron flux profiles are compared against measurements, with very good agreement.....
...The effects of order of fractional derivative, relaxation time and radioactive decay constant on the neutron flux profile are examined.....
...A good agreement is found comparing the critical boron concentration and a set of pin-level neutron flux profiles against measurements.....
中性子束スペクトル
学術論文
...In the systematic modelling and simulation of a zero-power molten salt reactor, the radius and the feedback effects are studied for a eutectic based system, while a heavy metal rich chloride-based system are studied depending on the uranium enrichment accompanied with the effects on neutron flux spectrum and spatial distribution.....
...The fission product cross-section library that was used with the RODBURN code was produced by using the ORIGEN code fed with the neutron flux spectrum of the Es-Salam research reactor.....
...It was established that combinations of these parameters, which provide the possibility of inverting the population of the excitation levels of Gd-156 isotope nuclei were largely determined by the energy neutron flux spectrum in pulses.....
外の中性子束
学術論文
...The proposed method is to measure the neutron flux outside the spallation target in the four directions of the east, south, west, and north.....
...The purpose of serpentinite concrete, containing an increased amount of chemically bound water, is to soften the spectrum of the neutron flux outside the reactor, increasing the fraction of thermal neutrons in the spectrum, which is necessary for the operation of ionization chambers (IR) of the reactor control and protection system.....
中性子束レベル
学術論文
...Eleven Zircaloy-4 samples were irradiated in the Advanced Test Reactor at a variety of temperatures and neutron flux levels for up to 6.....
...In the current work a fast neutron MSR using chloride fuel is analyzed, specially analyzing the power production and neutron flux level in the Intermediate Heat Exchanger (IHX).....
中性子束率
学術論文
...The results show that (1) In the normal operation of the reactor, the neutron flux rate is attenuated by 10 orders of magnitude from the outermost component to the inner surface of the pressure vessel, and the shielding effect of the coolant on neutrons is more significant.....
...Besides, the sensor has a neutron to gamma-ray rejection ratio of 1568 at a thermal neutron flux rate of 135.....
生成される中性子束
学術論文
...Such calculations are necessary for estimating the neutron flux produced as a result of the interaction between fast particles (deuterons) arising from the injection of a high-energy atomic beam.....
...However, the optimization on the thermal neutron flux produced should be performed to gain a sufficient thermal neutron for boron neutron capture therapy purpose.....
予想される中性子束
学術論文
...This paper reports the test performed on a 3 layers converter prototype coupled to a GEMPix detector (Murtas in Radiat Meas 138:106421, 2020), carried out in order to study the possibility to produce a large-scale multi-layer neutron detector capable to reach high detection efficiency with high spatial resolution and able to sustain the high neutron flux expected in the new neutron spallation source under development like the ESS.....
...Incident beam currents established using results from 3-D SN and Monte Carlo full core models were employed as a starting point for the source term in a full-scale MCNP6 computational model of the neutron beam port system to predict the spatial and energy-dependent neutron flux expected to exit the beam pipe onto the imaging operations floor.....
科学ニュース
動画
画像
辞書
定義と意味
Neutron
名詞
Flux
名詞
動詞