4S reactor is a sodium-cooled fast reactor developed as a small-decentralized power supply. The name of “4S” in this reactor stands for Super-Safe, Small and Simple, and they show representative features of the reactor.
The purpose of the present work is to evaluate quantitatively the super-safety of 4S reactor, and the safety performance is analyzed with ARGO-3, which is a plant dynamics code of a sodium-cooled fast reactor.
In this evaluation, some events, such as Unprotected Loss of Flow (ULOF) and Unprotected Transient Overpower (UTOP), are selected as typical cases from various transients and accidents. After metrics concerned with safety design is defined for each event, it is evaluated with statistical methods whether each metric satisfies acceptance criteria in a given criteria level.
Result about ULOF is as follows. The coolant temperature in the nominal hottest assembly outlet, “Tc” is selected as metric, and the upper side value of 95% confidential section in Tc is below 900 °C that is acceptance criteria. Also in UTOP, it is shown that the fuel maximum temperature in the nominal hottest assembly, “Tf” satisfies acceptance criteria. This result shows that 4S reactor has margin for safety acceptance criteria. 相似文献
The rapid increase of interest in the field of biohybrid and biomimetic materials that exhibit improved structural and functional properties is attracting more and more researchers from life science, materials science, and nanoscience. Concomitant results offer valuable opportunities for applications that involve disciplines dealing with engineering, biotechnology, medicine and pharmacy, agriculture, nanotechnology, and others. In the current contribution we collect recent illustrative examples of assemblies between materials of biological origin and inorganic solids of different characteristics (texture, structure, and particle size). We introduce here a general overview on strategies for the preparation and conformation of biohybrids, the synergistic effects that determine the final properties of these materials, and their diverse applications, which cover areas as different as tissue engineering, drug delivery systems, biosensing devices, biocatalysis, green nanocomposites, etc. 相似文献
A unidirectional continuous-carbon-fibre-reinforced composite was subjected to stress in the direction perpendicular to the fibre direction. By X-ray diffraction, the stress on the incorporated fibre in the composite under transverse load was monitored, and the effects of the environment (water, heat) on stress transfer in the composite were investigated. The adhesion between the matrix and the fibre was irreversibly destroyed by the water absorption and/or cyclic heating, which is found to bring worse stress transfer to the incorporated fibre. X-ray diffraction is a powerful tool for monitoring the stress transfer and its environmental deterioration behaviour in the composite in situ and non-destructively. 相似文献
Improvements in defect detection and sizing capabilities for non-destructive inspection techniques have been required in order to ensure the reliable operation and life extension of nuclear power plants. For the volumetric inspection, the phased array UT technique has superior capabilities for beam steering and focusing to objective regions, and real-time B-scan imaging without mechanical scanning. In contrast to the conventional UT method, high-speed inspection is realized by the unique feature of the phased array technique. A 256-channel array system has developed for the inspection of weldment of BWR internal components such as core shrouds. The TOFD crack sizing technique also can be applied using this system. For the surface inspection, potential drop techniques and eddy current techniques have been improved, which combined the theoretical analysis. These techniques have the crack sizing capability for surface breaking cracks to which UT method is difficult to apply. This paper provides the recent progress of these phased array and electromagnetic inspection techniques. 相似文献
In 1996 a conversion efficiency of 17.1% had been obtained on 15 cm×15 cm mc-Si solar cell. In this paper, large-scale production technology of the high-efficiency processing will be discussed. Enlarging reactive ion etching (RIE) equipment size, technology of passivation, and fine contact grid with low resistance by screenprinted metallization, which is firing through PECVD SiN, have been investigated. 相似文献
The role of the ligamentum flavum (LF) in the pathogenesis of adolescent idiopathic scoliosis (AIS) is not well understood. Using magnetic resonance imaging (MRI), we investigated the degrees of LF hypertrophy in 18 patients without scoliosis and on the convex and concave sides of the apex of the curvature in 22 patients with AIS. Next, gene expression was compared among neutral vertebral LF and LF on the convex and concave sides of the apex of the curvature in patients with AIS. Histological and microarray analyses of the LF were compared among neutral vertebrae (control) and the LF on the apex of the curvatures. The mean area of LF in the without scoliosis, apical concave, and convex with scoliosis groups was 10.5, 13.5, and 20.3 mm2, respectively. There were significant differences among the three groups (p < 0.05). Histological analysis showed that the ratio of fibers (Collagen/Elastic) was significantly increased on the convex side compared to the concave side (p < 0.05). Microarray analysis showed that ERC2 and MAFB showed significantly increased gene expression on the convex side compared with those of the concave side and the neutral vertebral LF cells. These genes were significantly associated with increased expression of collagen by LF cells (p < 0.05). LF hypertrophy was identified in scoliosis patients, and the convex side was significantly more hypertrophic than that of the concave side. ERC2 and MAFB genes were associated with LF hypertrophy in patients with AIS. These phenomena are likely to be associated with the progression of scoliosis. 相似文献
We examined whether sulfated hyaluronan exerts inhibitory effects on enzymatic and biological actions of heparanase, a sole endo-beta-glucuronidase implicated in cancer malignancy and inflammation. Degradation of heparan sulfate by human and mouse heparanase was inhibited by sulfated hyaluronan. In particular, high-sulfated hyaluronan modified with approximately 2.5 sulfate groups per disaccharide unit effectively inhibited the enzymatic activity at a lower concentration than heparin. Human and mouse heparanase bound to immobilized sulfated hyaluronan. Invasion of heparanase-positive colon-26 cells and 4T1 cells under 3D culture conditions was significantly suppressed in the presence of high-sulfated hyaluronan. Heparanase-induced release of CCL2 from colon-26 cells was suppressed in the presence of sulfated hyaluronan via blocking of cell surface binding and subsequent intracellular NF-κB-dependent signaling. The inhibitory effect of sulfated hyaluronan is likely due to competitive binding to the heparanase molecule, which antagonizes the heparanase-substrate interaction. Fragment molecular orbital calculation revealed a strong binding of sulfated hyaluronan tetrasaccharide to the heparanase molecule based on electrostatic interactions, particularly characterized by interactions of (−1)- and (−2)-positioned sulfated sugar residues with basic amino acid residues composing the heparin-binding domain-1 of heparanase. These results propose a relevance for sulfated hyaluronan in the blocking of heparanase-mediated enzymatic and cellular actions. 相似文献