JOPSS - Search Results

Journal Articles

Implementation of a low-activation Au-In-Cd decoupler into the J-PARC 1 MW short pulsed spallation neutron source

Teshigawara, Makoto; Ikeda, Yujiro; Oi, Motoki; Harada, Masahide; Takada, Hiroshi; Kakishiro, Masanori*; Noguchi, Gaku*; Shimada, Tsubasa*; Seita, Kyoichi*; Murashima, Daisuke*; et al.

Nuclear Materials and Energy (Internet), 14, p.14 - 21, 2018/01

https://doi.org/10.1016/j.nme.2018.02.001

Times Cited Count：0 Percentile：0.01(Nuclear Science & Technology)

We developed an Au-In-Cd (AuIC) decoupler material to reduce induced radioactivity instead of Ag-In-Cd one, which has a cut off energy of 1eV. In order to implement it into an actual moderator-reflector assembly, a number of critical engineering issues need to be resolved with regard to large-sized bonding between AuIC and A5083 alloys by the hot isostatic pressing process. We investigated this process in terms of the surface conditions, sizes, and heat capacities of large AuIC alloys. We also show a successful implementation of an AuIC decoupler into a reflector assembly, resulting in a remarkable reduction of radioactivity by AuIC compared to AIC without sacrificing neutronic performance.

JAEA Reports

Development of the assessment tool for has migration scenario concerning sub-surface disposal

Sakatani, Keiichi; Nakamura, Yasuo; Tsuji, Tomoyuki; Nakatani, Takayoshi

JAEA-Data/Code 2014-020, 38 Pages, 2014/11

JAEA-Data-Code-2014-020.pdf:30.04MB

The safety assessment for sub-surface disposal of radioactive wastes should ensure that calculated dose will be lower than the dose assigned to the scenario in question over the whole evaluation period of hundreds of thousands years. We have developed several assessment tools for the safe disposal of radioactive wastes on the GoldSim platform, and calculated doses since JFY 2008. These assessment tools have been improved reflecting the last view of assessment. In addition, we have developed an assessment tool for the gas migration scenario. This report describes concept of assessment model and structure of tool for the gas migration scenario.

Journal Articles

Study on drop wise condensation by using functionalized heat transfer surface

Koizumi, Yasuo; Yoshizawa, Shota*

Proceedings of the ASME 2014 International Mechanical Engineering Congress and Exposition (IMECE 2014) (DVD-ROM), 7 Pages, 2014/11

The enhancement of drop wise condensation heat transfer by functionalizing a heat transfer surface was examined for 0.1 MPa steam. A gold-plated surface was used to produce the drop wise condensation. Rectangular-grooved heat transfer surfaces were adopted to functionalize the heat transfer surface. The size of the grooves were 2 mm 2 mm 2 mm, 3 mm 3 mm 3 mm and 2 mm 3 mm 2 mm (depth top width bottom width), respectively. The heat flux of the grooved surface was larger than that of the plain gold-plated surface. When the groove size was 2 mm 2 mm 2 mm and the top parts and the walls of grooves were plated with gold, the heat transfer rate augmentation was highest; the augmentation rate was 1.53. Since to increase the width of the top part of the grooves tended to bring the quality of the surface structure close to the plain surface, it was not right direction. It was also implied that to make summits and troughs on the surface to collect condensate tended to expose the summit part to steam more, which might result in the heat transfer augmentation.

Journal Articles

Development of large scale fusion plasma simulation and storage grid on JAERI Origin3800 system

Idomura, Yasuhiro; Adachi, Masaaki*; Gorai, Kazuo; Suzuki, Yoshio; Wang, X.*

Purazuma, Kaku Yugo Gakkai-Shi, 79(2), p.172 - 187, 2003/02

https://doi.org/10.1585/jspf.79.172

Under the Numerical EXperiment of Tokamak (NEXT) research project, various fluid, particle, and hybrid codes have been developed. These codes require a computational environment which consists of high performance processors, high speed storage system, and high speed parallelized visualization system. In this paper, the performance of the JAERI Origin3800 system is examined from a point of view of these requests. In the performance tests, it is shown that the representative particle and fluid codes operate with % of processing efficiency up to 512 processors. A storage area network (SAN) provides high speed parallel data transfer. A parallel visualization system enables order of magnitude faster visualization of a large scale simulation data compared with the previous graphic workstations. Accordingly, an extremely advanced simulation environment is realized on the JAERI Origin3800 system. Recently, development of a storage grid is underway in order to improve a computational environment of remote users. The storage grid is constructed by a combination of SAN and a wavelength division multiplexer (WDM). The preliminary tests show that compared with the existing data transfer methods, it enables dramatically high speed data transfer Gbps over a wide area network.