[en] Hydrogen absorption-desorption properties of UZr_0.29 alloy are investigated in detail at hydrogen pressures up to 0.4 MPa and over the temperature range of 300 to 723 K. It absorbs hydrogen up to 2.3 H atoms per F.U. (formula unit) by only one-step reaction and hence each desorption isotherm has a single plateau over nearly the whole hydrogen composition range. The enthalpy and entropy changes of the dissociation reaction are of -78.9 kJ·mol ^-1 H₂ and 205.3 J·(K·mol H₂)^-1 , respectively. The alloy shows high durability against powdering upon hydrogenation and may have good heat conductivity. It is predicted that UZr_0.29 alloy may be a suitable material for tritium treatment and storage

[en] The application of thermo-hydrogen processing (THP), that is the use of hydrogen as temporary alloying element to modify the microstructures of uranium and its alloys, is presented. It is found that after THP, a refinement in the microstructure with less nonmetallic element impurities, more pure phase constituent and more fine grain is achieved

[en] In muon tomography based on multiple Coulomb scattering, the scattering properties of cosmic-ray muons are distinctive even for the same target due to their different momentum distribution, which, to some extent, cast down the imaging resolution. For the purpose of suppressing or eliminating this effect, a multi-group model (MGM) of the momentum spectra of cosmic-ray muons was set up and validated by measuring the thicknesses of Pb slabs and by identifying the materials of unknown slabs. The results show that MGM can give a precise calculation of Pb slab thickness in the range of 1-16 cm, within an error of 5%. Moreover, MGM can also identify the materials of slabs by calculating the corresponding radiation lengths, which is especially effective for high-Z materials with an calculation error below 4%. (authors)

[en] Hydrogen absorption-desorption properties of UZr_0.29 alloy are investigated in detail at hydrogen pressures up to 0.4 Mpa and over the temperature range from 300 to 723 K. It absorbs hydrogen up to 2.3 H atoms per F.U. (formula unit) by only one-step reaction and hence desorption isotherm has a single plateau over nearly the whole hydrogen composition range. The enthalpy and entropy changes of the dissociation are of -78.9 kJ·mol^-1H₂ and 205.3J·(K·molH₂)^-1, respectively. The alloy shows high durability against powdering upon hydrogenation and may have good heat conductivity. It is predicted that UZr_0.29 alloy can be suitable material for tritium treatment and storage

[en] Hydrogen absorption-desorption properties of the UZr_0.29 alloy and uranium metal were investigated in detail at hydrogen pressures as high as to 0.4 MPa and over the temperature range of 300-723 K. Both UZr_0.29 alloy and uranium metal showed similar hydrogen isotopic effect and hysteresis effect. UZr_0.29 alloy absorbed hydrogen (deuterium) up to 2.3H (2.18D) atoms per F.U. (formula unit) by only one-step reaction and hence each desorption isotherm had a single plateau over nearly the whole hydrogen composition range. The UZr_0.29 alloy showed a little lower dissociation pressure than that of pure uranium; however, it exhibited high durability against powdering upon hydrogenation and may have good heat conductivity. The UZr_0.29 hydride has the potentiality to substitute pure uranium hydride as a material for tritium treatment and storage

[en] The XRD researches of tritium aging of U and LaNi₅ have been presented. The major effect of tritium exposure present in the XRD patterns for LaNi₅ is peak broadening. It was found that the effect disappeared after the helium-3 was removed by 1230 K. On the contrary, the peak broadening of the XRD patterns for aged uranium samples was inconspicuous. The tritium aging effects in the equilibrium desorption isotherms were also slight

[en] A precise, detailed description of the characteristics (such as flux, energy spectrum and angular distribution) of the natural cosmic-ray muons was significant for muon tomography. However, the muon characteristics may vary from day to day, and location to location, as a result of the effects of the solar cycle, geomagnetic field and atmosphere. For a comprehensive study on the effects, a Monte Carlo simulation was applied based on the 1976US model of atmosphere to explore how the flux, energy spectrum and angular distribution of muons were changed as the measuring conditions varied. The data were obtained using the code 'Cosmic RaY generator' (CRY). The results demonstrated that the flux was reduced at the solar maximum or near the equator, where the geomagnetic field blue-shifted the spectrum. As well, the flux was definitely increased at elevated locations while the mean energy dropped away. The simulation results agreed well with previous experimental data. (authors)

[en] The reaction of LiH with vapor in atmosphere and Ar was in-situ investigated by laser Raman spectroscopy and atomic force microscope (AFM), etc. Experiments show that a product layer composed of LiOH, LiOH·H₂O and Li₂CO₃ forms as a result of the immediate reactions of LiH with H₂O and CO₂. The reaction velocity differs at distinct locations. In detail, the product distribution in depth and the variation rules of Raman intensity were discussed. Growth rates of surface products at different time were measured by AFM. Owing to stress release, microcracks appear in growing process, redounding to continuous penetration of H₂O through the product layer into LiH bulk for further reactions. The reaction of LiH with H₂O was considerably dependent on humidity that even in Ar with purity up to 99.995%, LiOH was still identified. (authors)

[en] The crystal structure of LaNi₅ alloy after longterm storage of tritium was investigated by means of X-ray diffraction (XRD). The results show broadened peaks on the XRD spectra of the specimens compared with that of the as-received ones, indicating clear aging effects of the alloy. The main reason causing the aging effects of the alloy is likely due to the tritium produced ³He, which might induce dislocation sub-structures in the crystal. The alloy shows the ability to be near fully recovered through high temperature treatment. (authors)

[en] A method for optimizing the most effective neutron multiplicity counter was proposed. The method used program of genetic algorithm and Monte Carlo method which coded by C + + to get ³He tubes assignment to maximize counter efficiency. The results validate the genetic algorithm based on Monte Carlo code for neutron calculations of more than 1000 valid assignment of ³He is effective. (authors)