Atomistic modeling of the interaction of cladding elements (Fe, Ni, Cr) with U-Zr fuel

Atomistic simulations of U-Zr fuel and its interaction with Fe, Ni, and Cr using the BFS method for alloys are presented. Results for the γU-βZr solid solution are discussed, including the behavior of the lattice parameter and coefficient of thermal expansion as a function of concentration and temperature. Output from these calculations is used to study the surface structure of γU-βZr for different crystallographic orientations, determining the concentration profiles, surface energy, and segregation behavior. The analysis is completed with simulations of the deposition of Fe, Ni and Cr on U-Zr substrates with varying Zr concentration. All results are discussed and interpreted by means of the concepts of strain and chemical energy underlying the BFS method, thus obtaining a simple explanation for the observed Zr segregation and its influence in allowing for cladding elements diffusion into the U-Zr fuel.     

Determination of mass attenuation coefficients, effective atomic and electron numbers for Cr, Fe and Ni alloys at different energies

The total mass attenuation coefficients (μ_m), for Cr, Fe, Ni and Fe_xNi_1−x (x = 0.8, 0.7, 0.6, 0.5, 0.4, 0.3 and 0.2), Fe_xCr_yNi_1−(x+y) (x = 0.7, y = 0.1; x = 0.5, y = 0.2; x = 0.4, y = 0.3; x = 0.3, y = 0.3; x = 0.2, y = 0.2 and x = 0.1, y = 0.2) and Ni_xCr_1−x (x = 0.8, 0.6, 0.5, 0.4 and 0.2) alloys were measured at 22.1, 25.0, 59.5 and 88.0 keV photon energies. The samples were irradiated with 10 mCi Cd-109 and 100 mCi Am-241 radioactive point source using transmission arrangement. The γ- and X-rays were counted by a Si(Li) detector with a resolution of 160 eV at 5.9 keV. Total atomic and electronic cross-sections (σ_t and σ_e), effective atomic and electron numbers (Z_eff and N_eff) were determined experimentally and theoretically using the obtained mass attenuation coefficients for investigated 3d alloys. The theoretical mass attenuation coefficients of each alloy were estimated using mixture rule. The experimental values were compared with the calculated values for all samples.     

XRF法无标分析人造金刚石原料锭中Fe、Ni、Cr、Co组分及其分布

介绍了用X射线荧光光谱(XRF)法无标分析人造金刚石原料锭样品的制备和测量方法.用车加工制备出了满足XRF测量的分析试样,应用Spectraplus无标分析软件实现了对人造金刚石原料锭中Fe、Ni、Cr、Co组分及其分布的无标分析,该方法简便、快速.     

Gamma-Ray Production Cross Sections for Interactions of 14.8 MeV Neutrons with O,Na, Al,Cl, Cr,Fe, Ni,Cu and Pb

Production cross sections for 85 discrete γ-rays at 125° were measured with a Ge(Li) detector for interactions of 14.8 MeV neutrons with natural samples of O, Na, Al, Cl, Cr, Fe, Ni, Cu and Pb. The obtained cross sections were compared with the results of previous works. For O, Na, Al, Cr and Ni, the present results agree with the previous data measured with monoenergetic neutron sources; for Cl, Fe, Cu and Pb, the present results are larger than the previous data. In comparison between the present results shown by histograms of γ-ray energy and unfolded data, a considerable discrepancy is found from some of the previous data for Fe.     

Excitation functions of (n,p) reactions for stable isotopes of Cr,Fe and Ni from threshold to 20 MeV

The excitation functions of (n,p) reactions for the stable isotopes of Cr, Fe and Ni were calculated using EMPIRE 3.0 β1 (ARCOLE) from threshold to 20 MeV. The cross-sections are calculated using full featured Hauser–Feshbach statistical model with pre-equilibrium effects by invoking DEGAS option in the code. A good agreement between the calculated and experimental data (EXFOR data base) as well as evaluated data is obtained with option of neutron and proton potentials by Koning (Global) and HFB parity dependent nuclear level density. This is an important step to the validation of nuclear model with superior predictive power. The compound nucleus and pre-equilibrium reaction mechanisms as well as the isotopic effects were also studied.     

Alpha Emission Spectra of 27Al, 50,52Cr, 55Mn, 54,56Fe, 58,60Ni Nucleus for Neutron Induced Reaction

The design of novel nuclear facilities, fusion as well as fission reactors, requires the knowledge of all properties of relevant materials, including the nuclear differential cross sections for a careful selection. The nuclear cross sections data for gas production via particle (neutron, proton, alpha, etc.) induced reactions are great importance in the domain in the fusion reactor technology, particularly in the calculation of nuclear transmutation rates, nuclear heating and radiation damage due to gas formation. In fusion reactor structures, a serious damage mechanism has been gas production in the metallic resulting from diverse nuclear reactions, mainly through (n, p) and (n, α), (n, d), (n, t). In the present study, by using equilibrium reaction mechanisms, the (n, xα) reaction alpha emission spectra for ²⁷Al, ^50,52Cr, ⁵⁵Mn, ^54,56Fe, ^58,60Ni isotopes were investigated from 9 to 15 MeV incident neutron energy. The equilibrium results have been calculated by using the hybrid model, the geometry dependent hybrid model. Calculation results have been also compared with the available measurements in literature.     

SRXRF研究苔藓植物对Pb/Fe/Cr污染的生物监视和累积特征

为研究苔藓植物对环境污染的累积特性和生物监视机理,用加入不同浓度的Pb、Fe、Cr培养基对二代扩繁后的小立碗藓进行胁迫试验,用同步辐射X射线荧光分析技术（SRXRF）测定藓体内金属元素含量,用微束荧光扫描技术（μ-SRXRF）分析了Cr、K等元素在苔藓叶和茎中的精细分布特征。结果表明,在单一重金属或复合重金属元素的胁迫下,藓体内污染金属元素的含量与培养基中相应元素的浓度呈现正相关,小立碗藓的受伤害程度随重金属元素浓度的增加而加重。重金属的胁迫导致小立碗藓吸收K、S等营养元素的能力急剧下降,且小立碗藓茎中K的吸收浓度由于受到过量Cr的拮抗作用而逐步降低。     

Dilute-impurity hyperfine fields in Fe,Co, Ni,and Gd

All the available experimental data on the hyperfine fields in the ferromagnetic hosts of Fe, Co, Ni, and Gd have been collected and tabulated. The best values for dilute-impurity hyperfine fields in Fe, Co, and Ni hosts are plotted as functions of the solute atomic number. Some useful relations of the curves to impurity electronic configurations are pointed out.     

Level excitation cross sections of Mg,Cr52, Ni58, Ni60 and Nb93 by inelastic neutron scattering

The excitation cross sections of certain levels of Mg²⁴, Mg²⁵, Mg²⁶, Ni⁵⁸, Ni⁶⁰ Cr⁵², and Nb⁹³ by neutrons were measured over the energy range 1 to 4 MeV. Experimental results are compared with calculated results obtained on the basis of the optical model of the nucleus from the Woods-Saxon potential.Translated from Atomnaya Énergiya, Vol. 16, No. 2, pp. 103–110, February, 1964     

二氧化铀芯块中微量Mn、Cr、Ni、Mo、Th的测定方法改进

硝酸溶解二氧化铀芯块,采用TBP树脂连续分离Mn、Cr、Ni、Mo、Th五种元素,等离子体发射光谱(ICP-OES)法测定Mn、Cr、Th,石墨炉原子吸收(GAAS)法测定Ni、Mo。结果表明:3mol/L硝酸介质中,U、Th被TBP树脂吸附,Mn、Cr、Ni、Mo 4种元素直接进入接收液(A),继续用6 mol/L盐酸平衡柱子,弃去8mL死体积后,此时Th淋洗进入接收液(B)。接收液为高酸基体,元素浓度低,故将接收液蒸至近干,稀酸溶解测定。采用标准物质(GBW04242)对该方法进行验证,测定值均在标准值的置信区间内。     

Zr（Fe,Cr）2金属间化合物的氧化

用非自耗电弧炉熔炼了比值(重量比值)不同的Zr(Fe,Cr)_2,并在773K和973K的空气中氧化。经X射线衍射和电子衍射分析表明:当Fe/Cr≤4.5时,Zr(Fe,Cr)_2,是MgZn_2型(六方)的Laves相,它的晶格常数随Fe/Cr比增加而收缩。Zr(Fe,Cr)_2氧化后生成的稳定氧化物是单斜ZrO_2和六方(Fe,Cr)_2O_3。在形成稳定氧化物之前,还会出现亚稳定的立方ZrO_2。根据本实验结果讨论了Zr-4合金中Zr(Fe,Cr)_2第二相对腐蚀性能的影响。     

机械合金化Fe0.6Ni0.4体系的结构研究

利用XAFS(X射线吸收精细结构)和XRD(X射线衍射)方法研究了机械合金化Fe0．6Ni0.4系统在制备过程中的晶体结构和Fe原子的局域配位环境。结果表明，球磨5h，样品中Fe、Ni原子开始产生合金化，但仍然为bcc和fcc混合的两种物相；球磨10h后，bcc结构Fe的特征配位峰消失，转化为fcc结构，随着球磨时间的增加，配位无序度逐渐增大；球磨40h后，Fe原子的近邻结构又有新的变化，是由多种物态组成的混合物。     

The effect of Fe,Ni and W impurities on uranium diffusion in uranium monocarbide

The self-diffusion of uranium with U-233 as tracer was measured in stoichiometric UC which was doped with Fe, Ni or W impurities. The impurities were added by flash evaporation on the UC and subsequent diffusion into the UC. Uranium diffusion was increased in the doped samples as compared to undoped UC at all temperatures studied (1380 to 2200°C). The increase was most pronounced (more than a factor of 100) at low temperatures. Simultaneously, pronounced grain-boundary penetration was observed at low temperatures, possibly due to eutectic formation at the grain boundaries. The ratio of grain boundary to lattice diffusion coefficients at 1380°C was of the order of 3 × 10⁴. The present data serve to explain some of the scatter of the literature data and correlate well with the known increased rate of sintering of Ni-doped UC.     

Ranges of projectiles with 8 ≤ Z ≤ 20 in Ti,Fe, Ni,Cu, Ag,and Au for energies of 0.0125 to 12.0 MeV/nucleon

Electronic stopping powers of various light elements in Ti, Fe, Ni, Cu, Ag, and Au have been reported recently. Earlier, measurements were made for the stopping of ¹⁶O in Ni, Ag, and Au. With the aid of the Northcliffe-Schilling stopping-power tables these values were extrapolated to values of $\text{E}\text{A}$ equal to 0.0125 and 12.0 MeV/amu. Ranges calculated from these stopping-power values and the stopping powers themselves are presented.