[en] Based on the conformal mapping, Green function method was applied in hexagonal geometry. Conformal mapping was used to map a hexagonal node to a rectangular node before transverse integration. Then, the transverse integration equations were resolved using Green function method with the second boundary condition. A three dimensional multi-energy-groups static program NACK was programmed based on those theories. The code was verified by VVER-1000-type core without the reflector, VVER 440-type three-dimensional two-energy-groups core and two-dimensional core with discontinuity factors. The eigenvalue error is less than 50 pcm, and the maximum relative error of the node average power is less than 2%. The accuracy of NACK is as good as that of other advanced node method codes. (authors)

[en] Using colloid SiO₂ source with boron and aluminum, the fast reverse recovery diode was made. Its t_rr is shorter than 5 μs and the inverse voltage is higher than 1000 V. The structure features and diffusive techniques are described

[en] Microdosimetric spectra and radial dose distribution of ²³⁹Pu α particles were measured by the cylindrical flowing tissue equivalent proportional counter with larger volume. Because of the best collimated beam traverse in TEPC (tissue equivalent proportional counter), the probability of energy deposition per ion traversal R_b is 1. The measured dose-mean specific energy z_1D from single-event varies strictly in accordance with formula z_1D =3D ab^-2, b is the radial distance from track core. The method of determination of the coefficient a is given

[en] Through analyses of the field tracer migration test results of tritium in unsaturated loess located in semi-arid area, it is found that the longitudinal concentration distributions of ³H are symmetry at higher relative concentration and non-symmetry at lower relative concentration. From processing of the migration test data the lateral concentration distribution variances (σ_y²) of ³H are obtained. σ_y² is 68.4 cm² (in pit A, at t = 780 d and depth of 76 cm) and 138.5 cm²(in pit B, at t = 779 d and depth of 110 cm), respectively. The lateral diffusion parameter is about one third of the longitudinal diffusion parameter. It is found from analyzing faster component of diffusion of ³H that the changes of both the faster component fractions, f(t, U_q),and the relative velocities, U_q, with time in pit B are not significant. Under the prerequisite, the concentrations calculated by faster component at point concerned are larger than that by conventional calculation under some conditions. It shows that it is not conservative to use the velocity of the center of mass as representative to conduct conventional calculation under some conditions

[en] The work concerns in the evolution of the nuclides in the sub-critical reactor of ADS. The analysis results indicate that the long-life nuclear waste can be transmuted in the ADS. The comparison between thermal and fast ADS demonstrate that the fast ADS has large power output, less minor actinide production and small fission products poisoning effect compared with thermal system

[en] Based on one-dimensional method of characteristics(MOC), a numerical model of pressure-wave propagation is presented. A special code is programmed to analyze and calculate water hammer resulted from rapid opening or closing of valve in the experimental sodium circus of fast breeder reactor(FBR). In the model, a new outer boundary condition, sodium-cavity is included. Model of bubble's discrete distribution is adopted to simulate generation and collapse of the bubble with the pressure's decreasing and increasing. The results demonstrate that the model of pressure-wave propagation is valid

[en] The rapidly image separate (RIS) method, a new kind of technique is developed, which allows authors to separate the images of different component by processing the different images of an object produced by microfocus X-ray beams of different energy. Its application to a acrylic-aluminum material has been proved through the experiment. The conditions for the realizing of the RIS method with the microfocus X-ray generator, including the voltage and amperage of the X-ray tube, the size of acrylic and aluminum material, the cause of error, are discussed. An idea to improve on the RIS method and the mathematical model of correcting error is given, and the vista of the method is also provided

[en] The carbon and oxygen contamination on Ti surface strongly influences the hydrogen absorption and desorption capability, and even can completely passivated the surface. The effect of C and O on Ti films is investigated by high-energy non-rutherford backscattering and elastic recoil detection. The experiment results show that the concentration gradient in the region of about 300 nm near the surface is very large due to the joint contamination of about 1.26 x 10¹⁶ cm^-2 C and 2.5 x 10¹⁶ cm^-2 O, and thermal releasing temperature is also increased greatly. Thin Ni film coated on the Ti film may considerably improve the hydrogen absorption and desorption capability

[en] HNO₃ oxidation method for removal of H₂C₂O₄ from H₂C₂O₄ stripping solution in TRPO process is studied. 5.5-7.5 mol·L^-1 HNO₃-0.30 mol·L^-1 H₂C₂O₄ mixed solution is evaporated at 90 degree C and H₂C₂O₄ can be decomposed and removed completely. After adding catalyst MnCO₃, the mixed solution is evaporated and distillated at 100 degree C, H₂C₂O₄ can be decomposed quickly. HNO₂ resulting from HNO₃ can oxidized Np(IV) to Np(V) and Np(VI) while 95% of Pu in the solution is as Pu(IV)

[en] The mathematic models and the stability analysis method are established for analyzing flow-induced-vibration of rod bundles in bounded axial flow. As applications, the vibration characteristics and stability of a 4-rod system are studied. With the flow velocity increment, the system experiences divergence instability and flutter instability. The existence of the axial flow induces the coupling of the movement of the rods. This coupling makes the very complicated vibration modes