GD阴极位敏探测器

本文叙述了GD阴极位敏探测器的设计和制作,得到的空间分辨率好于0.3mm,有效范围约30mm,非线性约1％。     

小样本成败型设备可靠性评估方法

小样本、高可靠性成败型设备可靠性评估是核工程和航天工程领域经常遇到的难题.本文系统地分析了若干可靠性评估方法,包括Bayes方法、改进Bayes方法以及Bayes网络方法,同时结合相应的仿真算例说明了方法的应用,最后对成败型设备可靠性评估问题提出了一些结论和建议.     

Coping with complexity

The author presents a short talk on intentional complexity, a form of complexity self-created by individuals such as occurs in experimental set ups     

Interaction of uranium-molybdenum fuel with an aluminum matrix with deep burnup

A thermodynamic analysis is used to calculate the phase and component composition of uraniummolybdenum fuel with burnup 200 GW·days/ton. The equilibrium composition of the gas phase, consisting mainly of gaseous cesium whose pressure reaches 30 kPa, is determined more accurately. The quantitative composition of the phase of solid solutions of tellurides, whose formation degrades the structure of a fuel granule, is presented. Thermal tests of the fuel composition (U–Mo)–Al were performed. The investigation was performed in the presence of simulators of the chemically active fission products of cesium and iodine at different temperature. The interaction zone of (U–Mo)–Al is investigated by means of metallography and scanning electron microscopy. The data obtained on the composition of the indicated zone made it possible to conjecture the character of interaction between the fuel material and the aluminum matrix.     

Forty-One Years with Zirconium

The MEGAPIE (Megawatt Pilot Experiment) Project has been primarily initiated in response to interest in the Accelerator Driven System (ADS). The ADS is a nuclear reactor concept with a fuel cycle which can burn minor actinide waste products from conventional reactors, while also taking advantage of the safety characteristics of a sub-critical reaction process. By this means, the fission chain reaction is maintained by additional neutrons generated by protons in a liquid-metal spallation target. The goal of the international MEGAPIE project is to design and construct such a target and install and test it over a period of one year in the SINQ spallation neuron source facility at the Paul Scherrer Institut (PSI). To aid the design process, Computational Fluid Dynamics (CFD) is being used to optimise the thermal- hydraulic behaviour of the target. Results obtained so far indicate that it should be possible to remove 700 kW of heat deposited by the proton beam in the target, under steady-state conditions (40kg/s total Lead Bismuth Eutectic flow rate), without peak window temperature rising above about 385°C, when using a bypass flow of 2.5 kg/s and a slanted- end guide tube. A tentative peak window temperature of 400°C is currently considered allowable, on the basis of material strength after irradiation, and CFD simulation is currently being validated by suitable LBE experiments in similar geometry.     

Experience with piping in German NPPs with respect to ageing-related aspects

Thirteen nuclear power plants (NPPs) with pressurized water reactors (PWRs) and six plants with boiling water reactors (BWRs) are currently in operation in Germany. For almost 25 years, GRS has been systematically evaluating the operating experience of these plants. In this paper, the operating experience relating to piping damage in safety-relevant systems of German plants with light water reactors (LWRs) is evaluated with respect to ageing-related effects. The experience with actions taken against piping degradation is illustrated by examples. The results of the evaluation confirm the conservativeness of the safety concept chosen for the design of German NPPs with LWRs, as well as the effectiveness of ageing management.     

Dynamic characteristics of rectangular twisted beam with fins surrounded with fluid

This study investigates the vibration characteristics of rectangular twisted beam and the safety assessment of the potential for fretting-wear damages caused by foreign object. To get the natural frequency, corresponding mode shape and participation factor, modal analyses are performed for a twisted beam with fins submerged in fluid of hexagonal cylinder. Special emphases are on the effects of fins, boundary conditions at both ends, fluid surrounding the beam and the number of turns on the modal characteristics, which are expressed in terms of the natural frequency and corresponding mode shape. Also, the wear rate caused by foreign object is calculated using the Archard formula and the remaining life of the beam is predicted.     

Diffusion with reversible trapping in a slab with an eroding boundary

The problem of transient diffusion with reversible trapping of atoms in a slab which has an eroding boundary and subjected to boundary conditions of the third kind has been solved. Numerical results are presented using the zeroth order solution. The results are found to be sufficiently accurate for all cases of practical interest except when the extraneous source distribution peaks very close to the moving boundary.It is also shown that a quasi-steady-state condition can be assumed to exist after the initial transients have passed; with such an assumption the analysis is significantly simplified. The accuracy of the quasi-steady-state analysis is examined by comparing numerical results obtained by the quasi-steady-state analysis against those obtained by the general analysis.     

Operating experience with a power-generating unit with a BN-600 reactor

Beloyarsk Nuclear Power Plant. Main Science Center of the Russian Federation — Physics and Power Engineering Institute. OKBM. Translated from Atomnaya énergiya, Vol. 80, No. 5, pp. 330–337, May, 1996.     

Design and optimization of an equilibrium reload with MOX fuel with minor actinides

In this work the design and optimization of an equilibrium core for a boiling water reactor (BWR), loaded with fuel composed of plutonium and minor actinides (Np, Am and Cm), is presented. The plutonium and minor actinides are obtained from the recycling of the spent fuel of a BWR, and are mixed with depleted uranium obtained from the enrichment tails. The design and optimization of the equilibrium reload is achieved in two steps. In the first step, the fuel assembly is adjusted and the reload pattern is designed, in order to obtain the target cycle length. In order to improve the shutdown margin, two actions were taken: to increase the boron-10 content in the control rods, and to add a burnable absorber (gadolinia) in some fuel rods. In the second step, the reload pattern, obtained in the first step, is optimized to maximize the energy, under the thermal and reactivity margins constraints; a system based on Genetic Algorithms was used in the optimization process. Results show that 5% more energy was obtained with the optimized reload.     

Accelerators with similar orbits

We obtain the conditions that must be satisfied by a magnetic system in order that the frequencies of radial and vertical betatron oscillations be independent of the particle momenta (in this case the orbits are called dynamically similar). In such systems mere should in principle be no excitation of betatron oscillations associated with synchrotron oscillations and other phenomena. A magnetic field\(H_0 \left( {\theta } \right)\left( {{{r_0 } \mathord{\left/ {\vphantom {{r_0 } r}} \right. \kern-\nulldelimiterspace} r}} \right)^{\Pi _0 } \) with n₀ = const produces both geometric and dynamic similarity of the orbit. In weak-focusing accelerators with segments (race tracks) and in strong-focusing proton synchrotrons, the orbits are not dynamically similar. In order to obtain this kind of similarity in the first case, in addition to n₀ = const it is necessary that the magnet sectors have a common center. Different types of annular synchrocyclotrons are considered. In the first type the centers of neighboring magnet sectors are located on different sides of the doughnut and in the second type at the same point (at the center of the accelerator). In the second type the orbits are dynamically similar, unlike those of the first. It is shown mat it is possible to design an annular synchrocyclotron in which the particles can move with stability simultaneously in both directions within the doughnut.     

Reactor statics with feedback

A diffusion theory model is presented for a slab reactor with coolant temperature feedback. A dimensionless feedback number is introduced and shown to be the determining physics parameter for (power dependent) critical sizes and spatial flux distributions. For the latter, the exact solution contains elliptic functions, but an approximation with three spatial modes is found to give satisfactory results. Two methods to evaluate the coefficients of the modal expansion are presented.     

Accelerators with similar orbits

We obtain the conditions that must be satisfied by a magnetic system in order that the frequencies of radial and vertical betatron oscillations be independent of the particle momenta (in this case the orbits are called dynamically similar). In such systems mere should in principle be no excitation of betatron oscillations associated with synchrotron oscillations and other phenomena. A magnetic field with n₀ = const produces both geometric and dynamic similarity of the orbit. In weak-focusing accelerators with segments (race tracks) and in strong-focusing proton synchrotrons, the orbits are not dynamically similar. In order to obtain this kind of similarity in the first case, in addition to n₀ = const it is necessary that the magnet sectors have a common center. Different types of annular synchrocyclotrons are considered. In the first type the centers of neighboring magnet sectors are located on different sides of the doughnut and in the second type at the same point (at the center of the accelerator). In the second type the orbits are dynamically similar, unlike those of the first. It is shown mat it is possible to design an annular synchrocyclotron in which the particles can move with stability simultaneously in both directions within the doughnut.     

131I标记卟啉化合物结合光动力治疗对肿瘤生长的抑制作用

利用放射性核素¹³¹I标记了卟啉化合物TPPOH和TPPNH₂得到¹³¹I-TPPOH和¹³¹I-TPPNH₂。建立了接种人肝癌细胞系SMMC-7721的裸鼠皮下肿瘤模型。将¹³¹I-TPPOH和¹³¹I-TPPNH₂直接注入肿瘤,考察了卟啉化合物、¹³¹I和光照对肿瘤生长的抑制效果。结果显示,¹³¹I-TPPOH和¹³¹I-TPPNH₂在注射14 d后仍大量滞留在肿瘤组织中。在β射线和光动力的双重作用下,两种¹³¹I标记的卟啉化合物均表现出对肿瘤生长较强的抑制能力。以上结果提示,基于“卟啉+¹³¹I+光动力治疗”结合的概念可开发一种新的实体肿瘤治疗剂。     

SPECT心血池显像评价阿霉素心肌毒性的价值

选择４９例非何杰金淋巴瘤和小细胞肺癌等患者，采用常规ＣＨＯＰ和ＣＡＶ方案进行的治疗，定期用ＳＰＥＣＴ检测患者左心功能，评价阿霉素（ＡＤＭ）对心肌的毒性作用，结果表明，化疗前后ＥＦ（射血分数）ＰＥＲ（高峰射血率）和ＰＦＲ（高峰充盈率）值比较，差别有显著性（Ｐ〈０．０５），体内的ＡＤＭ累积量愈大，ＥＦ，ＰＥＲ和ＰＦＲ值下降愈大，并以ＰＦＲ变化最敏感，提示ＳＰＥＣＴ心功能测定是评价患者ＡＤＭ心肌毒性的每     

Electrical properties of silicon diodes with pn junctions irradiated with Au swift heavy ions

Electrical properties of silicon diodes with p⁺n junctions irradiated with ¹⁹⁷Au⁺²⁶ swift heavy ions (energy E = 350 MeV, fluences of 10⁷ cm⁻² and 10⁸ cm⁻²) and silicon diodes irradiated with electrons (energy E = 3.5 MeV, fluences of 10¹⁵ cm⁻², 5 × 10¹⁵ cm⁻² and 10¹⁶ cm⁻²) have been investigated. Frequency dependences of the impedance, current-voltage characteristics and switching characteristics of these devices have been studied. Irradiation of the diodes with ¹⁹⁷Au⁺²⁶ ions at a fluence of 10⁸ cm⁻² leads to the formation of a quasi-continuous layer of irradiation-induced defects that enable a combination of characteristics such as a reverse resistance recovery time and direct voltage drop that are better than those for electron-irradiated diodes. Still, the irradiation of high-energy ions results in an increase in recombination currents that are larger than those obtained with electron irradiation, and causes more complicated frequency dispersion of the diode parameters.     

Interactions of Microwave with Plasmas

When plasma size scale is comparable with the wavelength of electromagnetic waves,W.K.B.solution isn‘t applicable.In this paper a new numerical solution technique to investigate interactions of microwave with plasmas is presented by using Runge-kutta method.The results of numerical solution coincide with that of analytical solution while the model is linear electron density profile in calculated accuracy.