Maintaining formation of multiple robotic wheelchairs for smooth communication

Suzuki, Ryota*; Kobayashi, Yoshinori*; Kuno, Yoshinori*; Yamada, Taichi; Yamazaki, Keiichi*; Yamazaki, Akiko*

International Journal on Artificial Intelligence Tools, 25(5), p.1640005_1 - 1640005_19, 2016/10

https://doi.org/10.1142/S0218213016400054

To meet the demands of an aging society, research on intelligent/robotic wheelchairs have been receiving a lot of attention. In elderly care facilities, care workers are required to communicate with the elderly in order to maintain both their mental and physical health. While this is regarded as important, having a conversation with someone on a wheelchair while pushing it from behind in a traditional setting would interfere with their smooth and natural conversation. So we are developing a robotic wheelchair system which allows companions and wheelchair users to move in a natural formation. This paper reports on an investigation to learn the patterns of human behavior when the wheelchair users and their companions communicate while walking together. The ethnographic observation reveals a natural formation of positioning for both companions and wheelchair users. Based on this investigation, we propose a multiple robotic wheelchair system which can maintain desirable formations for communication between wheelchairs.

Production of criticality safety standard data with Monte-Carlo code MVP / nuclear data library JENDL-3.2 validated using ICSBE data

Tonoike, Kotaro; Suyama, Kenya; Okuno, Hiroshi; Miyoshi, Yoshinori; Uchiyama, Gunzo

Proceedings of 9th International Conference on Nuclear Criticality (ICNC 2011) (CD-ROM), 8 Pages, 2012/02

The 1st version of criticality safety handbook of Japan was published in 1988. A criticality safety analysis code system JACS was validated, and minimum critical mass and safety limit mass of various fissile materials were calculated. During more than two decades since then, new critical experimental data were taken in the Static Critical Experiment Facility (STACY), and more precise benchmark data of wider range of fissile materials were accumulated by the International Criticality Safety Benchmark Evaluation Project (ICSBEP). Computational capability has greatly grown, and new codes and nuclear data have been developed. The 2nd version of the handbook utilizes the results of validation of the criticality analysis method with a continuous energy Monte-Carlo code MVP and a nuclear data library JENDL-3.2 using the benchmark data chosen from the ICSBEP handbook. Results of the benchmark calculation were statistically studied, from which the safety limit value of multiplication factor was derived as 0.98. Based on the conclusion, minimum critical mass and safety limit mass were calculated. Future plan of research activities on the criticality safety in JAEA will be also overviewed.

Second version of data collection part of nuclear criticality safety handbook (Contract research)

Okuno, Hiroshi; Suyama, Kenya; Tonoike, Kotaro; Yamane, Yuichi; Yamamoto, Toshihiro; Miyoshi, Yoshinori; Uchiyama, Gunzo

JAEA-Data/Code 2009-010, 175 Pages, 2009/08

JAEA-Data-Code-2009-010.pdf:13.1MB
JAEA-Data-Code-2009-010(errata).pdf:0.11MB

The report revised the Data Collection part of Nuclear Criticality Safety Handbook, which was published in 1988. This second version provided criticality data on homogeneous U-HO and UF-HF, which were not cited in the previous version, and increased those data on the medium-enriched uranium fuels. Calculations were performed mainly with the Continuous-Energy Monte Carlo Criticality Calculation Code, MVP, and the Japanese Evaluated Nuclear Data Library, JENDL-3 Revision 2, JENDL-3.2, both of which were developed at the late Japan Atomic Energy Research Institute (JAERI). Data on atomic number densities of actinide metal and oxide were additionally supplied, and nuclide compositions of irradiated fuels were improved from the first version. One million histories of neutrons were followed in benchmark calculations of critical experiments and in calculations of single-unit criticality data, i.e., critical mass, volume, dimensions, etc., to attain almost ten times higher precision than the first version.

Adsorption capacity of hydrogen isotopes on mordenite

Kawamura, Yoshinori; Onishi, Yoshihiro*; Okuno, Kenji*; Yamanishi, Toshihiko

Fusion Engineering and Design, 83(4), p.655 - 660, 2008/05

https://doi.org/10.1016/j.fusengdes.2008.02.004

In a fusion reactor system, a monitoring of hydrogen isotopes including tritium is necessary from the viewpoint of safety control. A gas chromatography using a cryogenic separation column is one of the methods for hydrogen isotope analysis. However, use of a refrigerant such as liquid nitrogen is a cause of long analysis time and is not suitable for easy installation. The development of the column material having separation capability at fairly high temperature is one of the solutions for these weak points. Synthesis zeolite such as molecular sieve 5A is a probable candidate. If the factor effected to the hydrogen adsorption property of the synthesis zeolite is clarified, it may lead to the development of the new zeolite optimized to the separation column. So, in this work, adsorption isotherms of hydrogen and deuterium for mordenite were investigated. The amount of adsorption per unit weight was larger than that of molecular sieve 5A.

Calculation of criticality condition data for single-unit homogeneous uranium materials in six chemical forms

Okuno, Hiroshi; Yoshiyama, Hiroshi; Miyoshi, Yoshinori

Journal of Nuclear Science and Technology, 43(11), p.1406 - 1413, 2006/11

https://doi.org/10.3327/jnst.43.1406

Single-unit criticality condition data were calculated for homogeneous uranium materials in six chemical forms for revision of the Data Collection section that was attached as the appendix to the Nuclear Criticality Safety Handbook. The calculated criticality condition data were the estimated critical and the estimated lower-limit critical masses and volumes of spheres, diameters of infinitely-long cylinders and infinite slab thicknesses for uranium materials in six chemical forms encountered in criticality safety evaluation of nuclear fuel cycle facilities. The calculation was made with a continuous-energy Monte Carlo criticality calculation code MVP and the Japanese Evaluated Nuclear Data Library JENDL-3.2. The values and precision of the present calculations were discussed in comparison with the literature and the previous results.

Material data for criticality transient phenomena analysis of MOX powder system; Data of MOX and zinc stearate powders (Contract research)

Yamane, Yuichi; Sakai, Mikio*; Abe, Hitoshi; Yamamoto, Toshihiro*; Okuno, Hiroshi; Miyoshi, Yoshinori

JAEA-Data/Code 2006-021, 75 Pages, 2006/10

JAEA-Data-Code-2006-021.pdf:24.75MB

Propety data of MOX, Zinc Stearate, etc. were investigated and examined as part of the development for criticality accident evaluation method for MOX fuel fabrication facility. Property data gathered for the powders of MOX, UO, Zinc Stearate, Tungsten and their mixture were density, specific heat, thermal conductivity and etc. as well as the data concerning fluidization or degree of mixing.

Benchmark analyses of criticality calculation codes based on the evaluated dissolver-type criticality experiment systems

Okuno, Hiroshi; Takada, Tomoyuki; Yoshiyama, Hiroshi; Miyoshi, Yoshinori

JAEA-Data/Code 2005-001, 117 Pages, 2005/11

JAEA-Data-Code-2005-001.pdf:9.37MB

Criticality calculation codes/code systems MCNP, MVP, SCALE and JACS, which are currently typically used in Japan for nuclear criticality safety evaluation, were benchmarked for so called dissolver-typed systems, i.e., fuel rod arrays immersed in fuel solution. The benchmark analyses were made for the evaluated critical experiments published in the International Criticality Safety Benchmark Evaluation Project (ICSBEP) Handbook: one evaluation representing five critical configurations from heterogeneous core of low-enriched uranium dioxides at the Japan Atomic Energy Research Institute and two evaluations representing 16 critical configurations from heterogeneous core of mixed uranium and plutonium dioxides (MOXs) at the Battelle Pacific Northwest Laboratories of the U.S.A.. The results of the analyses showed that the minimum values of the neutron multiplication factor obtained with MCNP, MVP, SCALE and JACS were 0.993, 0.990, 0.993, 0.972, respectively, which values are from 2% to 4% larger than the maximum permissible multiplication factor of 0.95.

Characterization of extreme ultraviolet emission from laser-produced spherical tin plasma generated with multiple laser beams

Shimada, Yoshinori*; Nishimura, Hiroaki*; Nakai, Mitsuo*; Hashimoto, Kazuhisa*; Yamaura, Michiteru*; Tao, Y.*; Shigemori, Keisuke*; Okuno, Tomoharu*; Nishihara, Katsunobu*; Kawamura, Toru*; et al.

Applied Physics Letters, 86(5), p.051501_1 - 051501_3, 2005/01

https://doi.org/10.1063/1.1856697

no abstracts in English

Validation of integrated burnup code system SWAT2 by the analyses of isotopic composition of spent nuclear fuel

Suyama, Kenya; Mochizuki, Hiroki*; Okuno, Hiroshi; Miyoshi, Yoshinori

Proceedings of International Conference on Physics of Fuel Cycles and Advanced Nuclear Systems; Global Developments (PHYSOR 2004) (CD-ROM), 10 Pages, 2004/04

This paper provides validation results of SWAT2, the revised version of SWAT, which is a code system combining point burnup code ORIGEN2 and continuous energy Monte Carlo code MVP, by the analysis of post irradiation examinations (PIEs). Some isotopes show differences of calculation results between SWAT and SWAT2. However, generally, the differences are smaller than the error of PIE analysis that was reported in previous SWAT validation activity, and improved results are obtained for several important fission product nuclides. This study also includes comparison between an assembly and a single pin cell geometry models.

Revised data for 2nd version of Nuclear Criticality Safety Handbook/Data Collection

Okuno, Hiroshi; Ryufuku, Susumu*; Suyama, Kenya; Nomura, Yasushi; Tonoike, Kotaro; Miyoshi, Yoshinori

JAERI-Conf 2003-019, p.116 - 121, 2003/10

https://doi.org/10.11484/jaeri-conf-2003-019

This paper outlines the data prepared for the 2nd version of Data Collection of the Nuclear Criticality Safety Handbook. These data are discussed in the order of its preliminary table of contents. The nuclear characteristic parameters (k, M, D) were derived, and subcriticality judgment graphs were drawn for eleven kinds of fuels which were often encountered in criticality safety evaluation of fuel cycle facilities. For calculation of criticality data, benchmark calculations using the combination of the continuous energy Monte Carlo criticality code MVP and the Japanese Evaluated Nuclear Data Library JENDL-3.2 were made. The calculation errors were evaluated for this combination. The implementation of the experimental results obtained by using NUCEF facilities into the 2nd version of the Data Collection is under discussion. Therefore, related data were just mentioned. A database is being prepared to retrieve revised data easily.