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61.
Wei Liu Akira Ohnuki Hiroyuki Yoshida Masatoshi Kureta Kazuyuki Takase Hajime Akimoto 《传热工程》2013,34(8):704-711
A new reactor concept of innovative water reactor for flexible fuel cycle (FLWR) is under development at Japan Atomic Energy Agency in cooperation with Japanese reactor suppliers. A design of 1,356 MWe high conversion boiling water reactor-type FLWR core, which has an instantaneous conversion ratio of 1.04, negative void coefficient, high burnup of 65 GWd/t, and 15-month operational cycle length, has been constructed. So far, studies on thermal-hydraulic characteristics have been performed for tight lattice core. Evaluation methods for the critical power and the pressure drop under both the steady and the transient states have been established, and a modified TRAC-BF1 code has been developed for the thermal-hydraulic design of the FLWR. In this paper, the thermal feasibility of the designed 1356MWe FLWR core is analyzed by using the modified TRAC-BF1 code. The analysis is first carried out for the current core design. It is confirmed that no boiling transition (BT) occurs under the steady state. However, the minimum critical power ratio (MCPR) is only about 1.08, and the BT is confirmed occurring under the postulated abnormal transient processes. Therefore, concretizations of the conditions that ensure the thermal feasibility of a natural circulation-type FLWR and a forced circulation-type FLWR are performed. As for the results, for a forced circulation-type FLWR, the operation-limited MCPR (OLMCPR) is 1.32, and the necessary minimum core coolant flow rate is 640 kg/(m2s). For a natural circulation-type FLWR, the OLMCPR is 1.19, and the necessary minimum core coolant flow rate is 560 kg/(m2s). 相似文献
62.
Shinji Kubo Masatoshi Futakawa Ikuo Ioka Kaoru Onuki Akihisa Yamaguchi 《International Journal of Hydrogen Energy》2013
Very harsh environments exist in the iodine–sulfur process for hydrogen production. Structural materials for sulfuric acid vaporizers and concentrators are exposed to high-temperature corrosive environments. Immersion tests were carried out to evaluate the corrosion resistance of ceramics and to evaluate corrosion-resistant metals exposed to environments of aqueous sulfuric acids at temperatures of 320, 380, and 460 °C, and pressure of 2 MPa. The aqueous sulfuric acid concentrations for the temperatures were 75, 85, and 95 wt%, respectively. Ceramic specimens of silicon carbides (SiC), silicon-impregnated silicon carbides (Si–SiC), and silicon nitrides (Si3N4) showed excellent corrosion resistance from weight loss measurements after exposure to 75, 85, and 95 wt% sulfuric acid. High-silicon irons with silicon content of 20 wt% showed a fair measure of corrosion resistance. However, evidence of crack formation was detected via microscopy. Silicon enriched steels severely suffered from uniform corrosion with a corrosion rate in 95 wt% sulfuric acid of approximately 1 g m−2 h−1. Among the tested materials, the ceramics SiC, Si–SiC, and Si3N4 were found to be suitable candidates for structural materials in direct contact with the considered environments. 相似文献
63.
Xiaojun Wang Takashi Takeda Naoto Hirosaki Shiro Funahashi Rong-Jun Xie 《中国稀土学报(英文版)》2018,36(1):42-48
Discovery of novel phosphors is extremely important to target the ever change of the solid state lighting technology. In this paper, we present a high-speed way to discover new phosphors, namely single-particle-diagnosis approach. This approach is based on investigating the crystal structure and luminescence of a tiny single crystal, without the necessity of the growth of large-size single crystals or the preparation of single phase powder samples. The concept of the approach and some new nitride phosphors explored by this approach are shown in this paper. 相似文献
64.
It has been said that nuclear energy is an important option for especially developing countries to satisfy their increasing energy demand. However, it will be difficult to deploy first of a kind nuclear power plant in developing countries because extensive safety demonstration has to be conducted in industrialized countries. On the other hand, it will be essential to present rigid proof of reliable operational experience to develop proper understanding of the safety features of new reactor systems among the people around the demonstration plant sites. One of the ways to solve the issue is to integrate existing technologies supported by a great deal of data and experience into a new reactor design. Based on the consideration, a small-sized district heating reactor system based on the pressurized water reactor (PWR) technologies combined with the fuel concept of high temperature gas cooled reactors (HTGRs) has been studied. The purpose of the combination of these two existing concepts is to take the best advantages of both excellent operational experience of PWRs and the integrity of HTGR fuel, coated particle fuel, against fission products release even at high temperature. We expect that this approach will help create a breakthrough to the current stagnation of nuclear power deployment. 相似文献
65.
A 155Eu/154SmPd3 (about 231 MBq) source for use with 155Gd Mössbauer spectroscopy was developed by a novel method. In the novel method, the isotopically enriched 154SmPd3 compound was prepared by the conventional solid state reaction of 154Sm(HCOO)3 and PdHx in a hydrogen atmosphere at 1273 K for 18 h, which is simpler than the previously reported method. In order to increase the reaction areas, palladium fine particles used to synthesize the PdHx hydride were prepared by a chemical solution process. Performance of the newly developed source was evaluated by observing the 155Gd Mössbauer spectra of known compounds, GdPd3 and cubic Gd2O3 at 12 K. The obtained results indicated that the developed source is fine enough to investigate the structural characteristic of various materials containing gadolinium. 相似文献
66.
67.
E Ngang H Matsufuji M Chino Y Goda M Toyoda M Takeda 《Shokuhin eiseigaku zasshi. Journal of the Food Hygienic Society of Japan》2001,42(5):298-303
HPLC analysis revealed that eight subsidiary colors existed in commercial Food Green No. 3 (fast green FCF, FD & C Green No. 3). Among them, four subsidiary colors C, F, G, and H were isolated by using preparative HPLC and their structures were determined by MS and NMR. They were the disodium salt of 2-[[4-[N-ethyl-N-(3- sulfophenylmethyl)amino]phenyl][4-[N-ethyl-N-(4- sulfophenylmethyl)amino]phenyl]methylio]-4-hydroxybenzenesulfonic acid (abbreviated as m,p-G-3), the sodium salt of 2-[[(4-N-ethylamino)phenyl][4-[N-ethyl-N-(3- sulfophenylmethyl)amino]-phenyl]methylio]-4-hydroxybenzenesulfonic acid [abbreviated as HSBA-(EA) (m-EBASA)], the sodium salt of 2-[[(4-N-diethylamino)phenyl][4-[N-ethyl-N-(3- sulfophenylmethyl)amino]phenyl]-methylio]-4-hydroxybenzenesulfonic acid [abbreviated as HSBA-(di-EA) (m-EBASA)], and the sodium salt of 2-[[4-[N-ethyl-N-(phenylmethyl)amino]phenyl][4-[N-ethyl-N-(3- sulfophenylmethyl)-amino]phenyl]methylio]-4-hydroxybenzenesulfonic acid [abbreviated as HSBA-(EBA)(m-EBASA)], respectively. HSBA-(di-EA) (m-EBASA) was a subsidiary color newly found in commercial Food Green No. 3. 相似文献
68.
69.
The gate-drain overlapped device (GOLD) structure is proposed to achieve high reliability and high performance in deep submicrometer MOSFETs. The GOLD device concept is different from that of drain-engineering methods such as the double-diffused drain (DDD) and lightly doped drain (LDD). GOLD eliminates the tradeoff between transconductance and breakdown voltage (hot-carrier, drain sustaining). The overlap effect of the GOLD devices is discussed using simulation and experiment. GOLD has a gate structure using a native oxide film (5-10 A) to obtain an overlapped fine structure. The process is also compatible with conventional LDD processes and is suitable for 0.3-0.5-μm-design-rule devices at 5-V operation, and 3-V operation 相似文献
70.