长寿命电气二次设备的加速试验方法

以继电保护装置为例对电气二次设备实际寿命进行了调研和分析,总结出目前影响电气二次设备寿命的主要因素、影响机理和相应的对策;重点以20年使用寿命为目标,利用影响因素结论构建了基于Weibull分布和Peck模型的应力-寿命加速试验方法,并根据贝尔实验室的推荐公式得出加速试验的基本参数。为验证电气二次设备寿命提供了试验的理论依据。     

Modeling and Drying of Carton Packaging Waste in a Rotary Dryer

This research aims at modeling the rotary drying of carton packaging waste and analyzing the energy performance of the process. Drying data were obtained in a semi-pilot rotary dryer, 0.45 m diameter and 2.7 m rotating drum long, operating with an air velocity of 1 m/s and air inlet temperature of 90°C and 10 rpm. Under the operating conditions employed, the analysis of the data showed that the energy performance of the drying process increased from 5 to 75% as the inlet wet solid feed rate increased from 1.8 to 19 kg/h. In addition, at this latter wet-solid feed rate, the reduction of the air velocity in the dryer to 0.8 m/s also led to an increase in the performance of drying process from 80 to 94%. Furthermore, with a 95% confidence interval, the model used was adequate to predict the air and solid temperature as well as the air humidity and the solids moisture content.     

小型长寿命核能系统燃料物理性能的研究

本文在简要说明世界上小型长寿命核能系统研究现状的基础上,提出了使用钍-铀燃料和铅-铋冷却剂构造小型长寿命堆芯的设想,并为此进行了一系列燃料物理性能的研究.对于长寿命核能系统的堆芯物理设计,使反应性随燃耗变动最小非常重要,同时应该尽可能地提高堆芯的燃耗以满足长寿命运行的需求.本文使用MCNP和MCBurn程序详细计算分析了使用不同的初始驱动燃料、不同栅格、燃料成分和类型、富集度条件下,燃料栅元的燃耗反应性变化等性能,并对其进行了能谱、转换比、富集度变化等方面的分析,经过对比初步确定了使用钍-铀燃料构造长寿命堆芯的物理条件,并以此为起点构造出一个堆芯,计算给出了反应性空泡系数等安全参数.     

Microbiological quality of aseptic packaging and the effect of pin-holes on sterility of aseptic products

The microbiological quality of aseptic packaging (the board for long-life milk) was good and viable counts were under 50cfu per package. The percentage of defective samples that had viable microorganisms after 7–14 days of pre-incubation was 54% (one pin-hole) and 54% (ten pin-holes) for coffee beverage packed in board B and 17% (one pin-hole) and 17% (10 pin-holes) for milk packed in board A. The differences in the percentage of defective samples between milk and coffee beverage and between board A and board B were significant, but no difference was observed between one and ten pin-holes. An increase in fat content or a decrease in protein content increased the permeation of milk components through the pin-holes. The microorganisms isolated from the products with artificial pin-holes were f actobacillus sp. (52%), Streptococcus sp. (48 %) and Enterobacteriaceae (34%).     

大功率长寿命连续波磁控管注入锁频技术

在工业生产中加热对象往往体积庞大,微波功率不够高将直接影响加热效果,并严重制约生产规模,远不能满足大规模工业连续生产的需求。简单将多只磁控管作为独立微波源进行非相干功率合成,造成了功率合成效率低、难以消除磁控管之间相互问的干扰。严重影响微波源的工作稳定性和工作寿命,甚至直接损坏微波源。普通连续波磁控管是一种复杂幅相特性微波器件,通常其幅度易受工作条件的影响、频率和相位随机变化、幅度和相位变化相互牵连,使得进行相干功率合成具有相当大的难度。而随着注入锁频技术的引入,注入锁频连续波磁控管将能很好的解决这些问题,可实现真正意义上的相干功率合成,为微波能大规模工业应用开辟广阔的前景。     

Extension of core life-time in fast breeder reactor by introducing inner blanket and doping minor actinides

In order to achieve a longer-life Fast Breeder Reactor (FBR) compared with conventional one, the feasibility study based on proto-type large scale sodium cooled FBR has been performed by utilizing a characteristic of a fertile material of minor actinides (MA) and an inner blanket arranged radially at the center of the core. The analytical results showed that the long-life core without the inner blanket could be achieved by doping MA into an active core because ²³⁸Pu transmuted from MA worked as the fissile material. In case of the core with the inner blanket, it was found that if MA is doped into the inner blanket, the longer-life core also could be achieved by shifting of the main fission reaction zone geometrically from the active core to the inner core due to producing of ²³⁸Pu in the inner blanket. It was also found that if MA is doped into both the inner blanket and the active core, the core life can be extended further. As for the safety characteristics, it has been confirmed that the sodium loss reactivity is improved in case of introducing the inner blanket due to the enhancement of neutron leakage. It has also been confirmed that the sodium loss reactivity is largely affected if the region of high neutron flux, that is the region of main fission reaction is voided.     

Microstructure-optimized concentration-gradient NCM cathode for long-life Li-ion batteries

Herein, a comprehensive investigation of the effect of calcination temperature on the physicochemical properties of full-concentration-gradient Li[Ni_0.78Co_0.10Mn_0.12]O₂ (FCG NCM78) and the electrochemical performance of FCG NCM78 cathodes was conducted. The electrochemical performance of the FCG NCM78 cathode was significantly influenced by the physical properties of FCG NCM78, such as crystallinity, compositional gradient, and morphology. The crystallinity of FCG NCM78 increased with increasing calcination temperature; however, the compositional gradient and radial alignment of rod-shaped primary particles increasingly disappeared at calcination temperatures exceeding the optimal calcination temperature. FCG NCM78 calcined at the optimal calcination temperature retained the morphological texture of its precursor and demonstrated high crystallinity; the resulting cathode exhibited remarkable cycling stability, thereby retaining 86.3% of its initial capacity after 4000 cycles, and superior rate capability due to the availability of nearly straight diffusion paths for Li-ion transport across adjacent primary particles. In contrast, excessively coarsened FCG NCM78 cathode particles, which are obtained at high calcination temperatures, develop permanent microcracks during cycling, thereby facilitating severe structural damage of the cathode material by parasitic surface reactions and the rapid deterioration of the solid electrolyte interphase layer on the graphite anode surface due to the crossover of dissolved transition-metal ions. Therefore, for superior electrochemical performance, the physicochemical properties of FCG cathode materials should be carefully optimized by controlling the calcination process.     

重水冷却钍基长寿命模块化小堆概念设计研究

基于传统压水堆(PWR)技术,提出一种重水冷却的钍基长寿命模块化小堆(RMSMR)的概念设计方案,采用二维模型系统分析并对比了PWR和RMSMR的燃料类型、慢化剂类型等参数,获得反应堆各项中子学参数的变化机理;然后基于二维计算结果提出了最终的三维堆芯设计方案,并开展了初步的中子物理和热工安全分析。研究表明,RMSMR在设计上采用三区燃料布置来展平功率,采用钍-铀燃料维持了负空泡系数,通过布置增殖包层提高了堆芯的转换比(CR);RMSMR采用了重水冷却剂可以使中子能谱硬化,从而提高CR,减小寿期反应性波动,增加堆芯寿期;RMSMR能够在100 MW电功率下维持6 a的安全运行。本文研究可为新型反应堆的设计发展提供借鉴。     

The utilization of thorium for long-life small thermal reactors without on-site refueling

Thorium cycle has many advantages over uranium cycle in thermal and intermediate spectrum nuclear reactors. In addition to large amount of resources in the world which up to now still not utilized optimally, thorium based thermal reactors may have high internal conversion ratio so that they are very potential to be designed as long-life reactors without on-site refueling based on thermal spectrum cores. In this study preliminary study for application of thorium cycle in some of thermal reactors has been performed.

We applied thorium cycle for small long-life high temperature gas reactors without on-site refueling. Calculation results using SRAC code show that 10 years lifetime without on-site refueling can be achieved with excess reactivity of about 10% dk/k.

The next application of thorium cycle has been employed in long-life small and medium PWR cores without on-site refueling. Relatively high fuel volume fraction is also applied to get relatively hard spectrum, small size, and high internal conversion ratio. In the current study we have been able to reach more than 10 years lifetime without on-site refueling for 20–300 MWth PWR with maximum excess reactivity of a few %dk/k.

The last application of thorium cycle has been employed in long-life BWR cores without on-site refueling. Relatively high fuel volume fraction is applied to get relatively hard spectrum, small size, and high internal conversion ratio. In the current study we have been able to reach more than 10 years lifetime without on-site refueling for 100–600 MWth BWR with maximum excess reactivity of a few %dk/k.     

^179Hf（n,2n）^178Hf^m2和^209Bi（n,2n）^208Bi反应截面的测量

用活化法测量相对于~(93)Nb(n,2n)~(92)Nb~m反应的~(179)Hf(n,2n)~(178)Hf~(m2)的反应截面和相对于~(27)Al(n,2n)~(24)Na反应的~(209)Bi(n,2n)~(208)Bi的反应截面。在中子能量为14.4 MeV处~(179)Hf(n,2n)~(178)Hf~(m2)反应的测量截面为(6.04±0.32)×10~(-31)m~2。在中子能量为14.6 MeV处~(209)Bi(n,2n)~(208)Bi反应的测量截面为(2279±173)×10~(31)m~2。在这些测量中,中子能量是用~(90)Zr(n,2n)~(89)Zr~(m+8)反应和~(93)Nb(n,2n)~(92)Nb~m反应的截面比法测定的。