基于Ad Hoc网络的SMR优化算法的研究

SMR是一种基于DSR算法的多路径路由算法,这种算法的本身具有明显的局限性。第一,它可能在存在多条不相关多路径路由的情况下选择两条相关多路径路由作为最后的主路由与备份路由;第二,它在目的节点只收到一个RREQ分组的情况下只生成一条主路由,而实际可能存在多条传输线路。针对SMR算法的局限性,本文提出一种改进的SMR算法—ISMR,该算法保证了两条路由的形成,保证了在存在多条不相关多路径路由情况下,一定会生成两条不相关多路径路由。     

Process simulation and integration of IGCC systems for H2/syngas/electricity generation with control on CO2 emissions

IGCC is a pre-combustion technology that can be effectively used to produce both hydrogen and electricity while reducing the greenhouse gas (GHG) emissions. Two process models are developed in Aspen Plus^® software and are compared techno-economically. The conventional design of IGCC process is taken as case 1, whereas, case 2 represents the conceptual design of sequential integration of reforming model with the gasification unit to enhance the syngas yield. The case 2 utilizes the steam generated in the gasification process to sustain the methane reforming process which consequently enhances both the H₂ production capacity and cold gas efficiency. It has been analyzed from results that case 2 can enhance the process performance by 4.77% and economics in terms of cost of electricity by 5.9% compared to the conventional process. However, the utilization of natural gas in the case 2 is considered as a standalone fuel so the process performance of NGCC power plants has been also incorporated to ensure the realistic analysis. The results also showed that case 2 design offers 3.9% higher process performance than the cumulative (IGCC + NGCC) processes, respectively. Moreover, the CO₂ specific emissions and LCOE for the case 2 is also lower than the case.     

Revising the Emergency Management Requirements for new generation reactors

The paper presents the application of a new risk-informed methodology for the identification of the Emergency Management Requirements (EMR) to a Generation II, Large size Reactor and a Generation III+ Small Modular Reactor.The results obtained in this test case demonstrate that the actual EMR is conservative, as expected, for the GenII reactor, while the new methodology could be applied for the definition of EMRs for the new generation Nuclear Power Plants, with a possible reduction of the emergency area without loss of safety level.By adopting both probabilistic and deterministic approaches, the study addresses possible accidents and corresponding release scenarios for the two types of reactor, calculates the areas where the accidents have an impact on the population and defines the new EMR considering the health effects on the population.     

Development of slope mass rating system using K-means and fuzzy c-means clustering algorithms

Classification systems such as Slope Mass Rating(SMR) are currently being used to undertake slope stability analysis. In SMR classification system, data is allocated to certain classes based on linguistic and experience-based criteria. In order to eliminate linguistic criteria resulted from experience-based judgments and account for uncertainties in determining class boundaries developed by SMR system,the system classification results were corrected using two clustering algorithms, namely K-means and fuzzy c-means(FCM), for the ratings obtained via continuous and discrete functions. By applying clustering algorithms in SMR classification system, no in-advance experience-based judgment was made on the number of extracted classes in this system, and it was only after all steps of the clustering algorithms were accomplished that new classification scheme was proposed for SMR system under different failure modes based on the ratings obtained via continuous and discrete functions. The results of this study showed that, engineers can achieve more reliable and objective evaluations over slope stability by using SMR system based on the ratings calculated via continuous and discrete functions.     

基于RG 1.183的先进小堆选址源项模型初步研究

在《用于评估核动力反应堆设计基准事故的替代放射性源项》RG 1.183所述的假想事故场景情况下,考虑目前大多数的先进小型压水堆地上-地下布置的设计特点,对传统大型压水堆选址源项计算模型做了改进:在原安全壳内放射性物质守恒方程的基础上,考虑辅助厂房的阻滞作用,建立辅助厂房内放射性物质守恒方程。并以某先进小型反应堆核电厂为例,利用新模型计算了代表核素的释放,与现有模型进行了对比。     

A CONVENIENT DOMINANT SELECTION MARKER FOR GENE TRANSFER IN INDUSTRIAL STRAINS OF SACCHAROMYCES YEAST: SMRI ENCODED RESISTANCE TO THE HERBICIDE SULFOMETURON METHYL

The SMR1-410 gene of S. cerevisiae, encoding resistance to the herbicide sulfometuron methyl (SM), was used as a dominant selection marker in yeast replicating and yeast integrating vectors for the transformation of wild type strains of baking, brewing (ale and lager), distilling, wine and sake Saccharomyces yeasts. Transformation of lithium treated cells by a YEp vector resulted in transformation frequencies ranging from 200 to 8,000 transformants per 10 ug of DNA. Utilizing a yeast integrating vector with SMR1–410 as the only yeast DNA sequences, it was demonstrated that a single copy of SMR1–410 is sufficient to confer stably inherited SM resistance. Thus the SMR1–410 sequence has the unique ability to act as a selectable marker and to also provide a site for chromosomal integration. Since transformants were resistant to levels at least seven fold higher than wild type strains the resistance phenotype was clearly expressed and easily scored in all industrial strains tested. Unlike other selection markers derived from mammalian or bacterial cells, SMR1–410 is derived from S. cerevisiae. Thus industrial utilization of this marker as a means of genetically improving food and beverage strains of Saccharomyces yeasts by recombinant DNA technology is enhanced, as government regulatory agencies are likely to view it in a more favourable light.     

Impacts of an ATF cladding on neutronic performances of the soluble-boron-free ATOM core

This article is mainly concerned with the impacts of various accident tolerant fuel (ATF) claddings on neutronics performances of a soluble-boron-free (SBF) small modular reactor (SMR) core. There are two ATF cladding concepts which are evaluated here: (a) coating Zircaloy-4 cladding with a thin layer of Cr or Cr alloys; (b) high-strength and oxidation-resistant claddings: stainless steel and FeCrAl. Comparisons between Zircaloy-4 and ATF claddings are done in terms of the cycle length, discharge burnup, pin peaking factor (PPF), burnup reactivity, and spectral change. Moreover, the ATF claddings are also compared in view of the rim effect, neutron absorption by the cladding and He production in the cladding. In addition, a linear reactivity model is used to estimate the required U-235 enrichment so that the cycle length with ATF claddings should be equivalent to that with the reference Zircaloy-4 case. Furthermore, impacts of a selected ATF cladding are then analyzed in a centrally shielded burnable absorber (CSBA)-loaded FA in terms of PPF, burnup reactivity, and spectral change. Based on the CSBA-loaded FA analysis, a minor modification of burnable absorber loading strategy in the SBF autonomous transportable on-demand reactor module core is proposed to adopt the selected ATF cladding without compromising the core performance. The lattice calculations are done using the Monte Carlo Serpent 2 code with the ENDF/B-VII.1 nuclear library, while the 3-D multi-physics core calculations are performed using a Monte Carlo-diffusion hybrid procedure.     

QH-1型填料在中等界面张力体系的应用──I.流体力学性能

通过对ＱＨ－１型扁环填料在中等界面张力体系中的流体力学性能的研究，得到了两相流动特性模型和分散相液滴直径的半经验关联式，并对ＱＨ－１型填料萃取塔连续相出口的夹带情况进行了检测．实验表明，在中等界面张力体系中，该填料仍具有通量大、夹带少的优点，为该种填料在湿法冶金、医药、环保等工业领域的应用提供了实验和理论基础．     

Influence of injection temperature and flow rate on mixing and stratification in small passively cooling enclosures

Thermal mixing and stratification phenomena may occur during the loss of a coolant accident or main steam line break accident in the containment of a Passive Containment Cooling System, or in the suppression pools in BWR. However, the present study pays insufficient attention to the thermal stratification phenomena in the containment of small modular reactors(SMR). In this paper, an investigation on the mixing and thermal stratification phenomena caused by the plumes or buoyant jets in SMR containments was carried out. The experiments were both conducted under non-adiabatic and adiabatic conditions for a steel containment. In each condition, two key parameters, inlet temperature, and flow rate were tested by controlling variables to identify their influence on the thermal stratification phenomenon. The visualization experiments illustrated the jet mixing and stratification development. The experiment results were compared with the numerical computation and they reached a good agreement.