Research and development on accelerator-driven transmutation system at JAERI

Japan Atomic Energy Research Institute carries out research and development on accelerator-driven system (ADS) to transmute minor actinides and long-lived fission products in high-level radioactive waste. The system is composed of high intensity proton accelerator, lead-bismuth spallation target and lead-bismuth cooled subcritical core with nitride fuel. About 2500 kg of minor actinide is loaded into the subcritical core. Annual transmutation amount using this system is 250 kg with 800 MW of thermal output. This transmutation amount corresponds to the amount of minor actinides produced from 10 units of 1GWe power reactors annually. A superconducting linear accelerator with the beam power of 20–30 MW is connected to drive the subcritical core. To maximize the transmutation efficiency, the nitride fuel without uranium, such as (Np, Am, Pu)N, is selected. The nitride fuel irradiated in the ADS is reprocessed by pyrochemical process followed by the re-fabrication of nitride fuel. Many research and development activities are under way and planned in the fields of subcritical core design, spallation target technology, lead-bismuth handling technology, accelerator development, and minor actinide fuel development. Especially, to study and evaluate the feasibility of the ADS from physics and engineering aspects, the transmutation experimental facility (TEF) is proposed under a framework of the High-Intensity Proton Accelerator Project.     

Animation of Biological Organ Growth Based on L-systems

In contrast with the growth of plants and trees, human organs can undergo significant changes in shape through a variety of global transformations during the growth period, such as bending or twisting. In our approach, the topology of a human organ is represented by a skeleton in the form of a tree or cycled graph. The length of skeleton growth can be simulated by an algebraic L-system that also produces discrete events. The paper shows how to include global transformations into the formalism of L-systems to obtain a continuous process. The shape of the organ is approximated by a number of ellipsoidal clusters centred at points on the skeleton. The proposed growth model of the organ continually responds to the positional changes of surrounding organs, thereby changing the organ shape locally. In our study, the stomach of a human embryo is used for the demonstration of organ development, and the methodology employed is also applicable to the animation of animal organs and their development.     

The allowable spacing for lattice data sampling by a round stylus tip and an assessment of the envelope surface

This paper deals with surface waviness assessment by a commercial three-dimensional stylus instrument. To measure macroscopic waviness curve on an engineering surface, it was proposed to use a round stylus tip of relatively large radius. Developed in this paper, is a method to obtain the appropriate stylus tip radius in accordance with the sample surface texture and the corresponding discrete spacing for lattice data sampling. On condition that any two adjacent height data points are well-correlated, the statistical mean height and the overall deviation of the 3-D undulation summit height are also presented for a functional evaluation of waviness curves or envelope surface.     

Illumination Morphing: Generating a Smooth Change of Illumination between Two Color Images

The paper proposes a method for generating a sequence of images with smooth change of illumination from two input images with different lighting conditions. The idea of the proposed method is based on image morphing. While conventional image morphing changes object shapes between two input images, here we focus on changing the illumination between two images. The proposed method uses isoluminance curves as a feature primitive. Isoluminance curves acquired from images are warped based on the correspondence of the curves between two images, and transformed luminance distributions are generated from the warped isoluminance curves. The proposed method called "illumination morphing" is able to generate smooth transition of luminance between two color images. The method does not need even the information about the light sources and 3D object models. The proposed method is a promising technique for many applications requiring a scene with variety of lighting effects, such as movies, TV games, and so on.     

Buried water molecules contribute to the conformational stability of a protein

This study sought to attain a better understanding of the contributionof buried water molecules to protein stability. The 3SS humanlysozyme lacks one disulfide bond between Cys77 and Cys95 andis significantly destabilized compared with the wild-type humanlysozyme (4SS). We examined the structure and stability of theI59A-3SS mutant human lysozyme, in which a cavity is createdat the mutation site. The crystal structure of I59A-3SS indicatedthat there were ordered new water molecules in the cavity created.The stability of I59A-3SS is 5.5 kJ/mol less than that of 3SS.The decreased stability of I59A-3SS (5.5 kJ/mol) is similarto that of Ile to Ala mutants with newly introduced water moleculesin other globular proteins (6.3 ± 2.1 kJ/mol), but isless than that of Ile/Leu to Ala mutants with empty cavities(13.7 ± 3.1 kJ/mol). This indicates that water moleculespartially compensate for the destabilization by decreasing hydrophobicand van der Waals interactions. These results provide furtherevidence that buried water molecules contribute to protein stability.     

Effects of an alloying element on a c-component loop formation and precipitate resolution in Zr alloys during ion irradiation

It is important to clarify the mechanisms of the dislocation loop formation, dissolution of precipitates to understand the degradation behavior of the fuel cladding tubes in light water reactors (LWR) under neutron irradiation. In this study, 3.2 MeV Ni ion irradiation was carried out at 400°C on Zircaloy-2 and two types of model alloys with and without Fe (Zr-1.5Sn-0.3Fe and Zr-1.5Sn). To understand the effects of hydrogen, 60 and 300 ppm pre-injected Zircaloy-2 samples were also irradiated. The microstructure was observed with a conventional transmission electron microscopy. Additionally, the dissolution of precipitates and the enrichment of the alloying element due to irradiation were analyzed using a spherical aberration (Cs)-corrected high-resolution analytical electron microscope. After ion irradiation at 400°C, the dissolution of Fe-enriched precipitates and the c-component dislocation loops were observed in the region of peak ion damage. Observations by STEM-EDS showed that Fe atoms were enriched in the c-component dislocation loops. On the contrary, the c-component dislocation loops were detected in Fe-containing alloys (Zircaloy-2 and Zr-1.5Sn-0.3Fe alloy) but were not in the Zr-1.5Sn alloy. These results indicate that the dissolution of Fe-enriched precipitates and the enhanced formation of c-component dislocation loops are essential for the degradation of LWR fuel cladding under irradiation.     

Properties of Gelatin Film from Horse Mackerel (Trachurus japonicus) Scale

Optimal conditions for extracting gelatin and preparing gelatin film from horse mackerel scale, such as extraction temperature and time, as well as the protein concentration of film‐forming solutions were investigated. Yields of extracted gelatin at 70 °C, 80 °C, and 90 °C for 15 min to 3 h were 1.08% to 3.45%, depending on the extraction conditions. Among the various extraction times and temperatures, the film from gelatin extracted at 70 °C for 1 h showed the highest tensile strength and elongation at break. Horse mackerel scale gelatin film showed the greatly low water vapor permeability (WVP) compared with mammalian or fish gelatin films, maybe due to its containing a slightly higher level of hydrophobic amino acids (total 653 residues per 1000 residues) than that of mammalian, cold‐water fish and warm‐water fish gelatins. Gelatin films from different preparation conditions showed excellent UV barrier properties at wavelength of 200 nm, although the films were transparent at visible wavelength. As a consequence, it can be suggested that gelatin film from horse mackerel scale extracted at 70 °C for 1 h can be applied to food packaging material due to its lowest WVP value and excellent UV barrier properties.     

淀粉和鱼糜品质对鱼糜凝胶性质的影响

本文探讨了糯玉米淀粉、马铃薯淀粉和变性淀粉对不同品质鱼糜凝胶形成能力的影响。结果发现,添加糯玉米淀粉后鱼糜制品的破断强度从266.57 g下降至175.00 g,硬度、胶黏性、咀嚼性也发生下降,而添加马铃薯淀粉可以使鱼糜制品的破断强度和部分质构得到显著提高。另一方面,冻融变性鱼糜制备的产品其破断强度、硬度、胶黏性、咀嚼性出现下降,添加马铃薯淀粉能提高其产品的凝胶性质。不论鱼糜是否发生冻融变性,添加三种淀粉后鱼糜制品的持水力和蒸煮时的吸水率都显著提高,但鱼糜制品的色泽变差。根据SDS-PAGE结果,可以发现添加糯玉米淀粉、马铃薯淀粉和变性淀粉都不会影响鱼糜蛋白之间的交联。SEM结果表明添加马铃薯淀粉可以使鱼糜凝胶网络结构变得更加致密有序,从而增强鱼糜制品的凝胶强度。以上结果表明,马铃薯淀粉比糯玉米淀粉和变性淀粉更适合作为鱼糜制品的辅料和添加剂。